Predictors of persistence of post-chemotherapy symptoms among survivors of solid tumor cancers

CONTEXT

Late or residual symptoms diminish quality of life for many cancer survivors after completion of treatment.

OBJECTIVES

Examine risk factors associated with persisting symptom burden after chemotherapy and the lack of symptom improvement over time.

METHODS

Survivors who completed curative-intent chemotherapy within two years for solid tumors were enrolled into a symptom management trial. There were 375 survivors with two or more comorbid conditions or one comorbid condition and elevated depressive symptoms (pre-defined risk factors in the trial design) who received interventions and 71 survivors without these risk factors who did not receive interventions. For all survivors, symptoms were assessed at intake, 4, and 13 weeks and categorized as mild, moderate, or severe based on the interference with daily life. The probabilities of moderate or severe symptoms and symptom improvement were analyzed using generalized mixed-effects models in relation to comorbidity, depressive symptoms, age, sex, race/ethnicity, employment, time since chemotherapy completion, and physical function. Multiple symptoms were treated as nested within the survivor.

RESULTS

Moderate or severe symptoms at baseline and the lack of improvement over time were associated with younger age and lower physical function over and above a greater number of comorbidities and elevated severity of depressive symptoms.

CONCLUSION

Risk factors identified in this research (younger age, lower physical function, greater comorbidity, and higher depressive symptoms) can be used to allocate resources for post-treatment symptom management for cancer survivors in order to relieve symptoms that do not necessarily resolve with time.

Safety and Efficacy of Tucatinib, Letrozole, and Palbociclib in Patients with Previously Treated HR+/HER2+ Breast Cancer

PURPOSE

To overcome resistance to antihormonal and HER2-targeted agents mediated by cyclin D1-CDK4/6 complex, we proposed an oral combination of the HER2 inhibitor tucatinib, aromatase inhibitor letrozole, and CDK4/6 inhibitor palbociclib (TLP combination) for treatment of HR+/HER2+ metastatic breast cancer (MBC).

PATIENTS AND METHODS

Phase Ib/II TLP trial (NCT03054363) enrolled patients with HR+/HER2+ MBC treated with ≥2 HER2-targeted agents. The phase Ib primary endpoint was safety of the regimen evaluated by NCI CTCAE version 4.3. The phase II primary endpoint was efficacy by median progression-free survival (mPFS).

RESULTS

Forty-two women ages 22 to 81 years were enrolled. Patients received a median of two lines of therapy in the metastatic setting, 71.4% had visceral disease, 35.7% had CNS disease. The most common treatment-emergent adverse events (AE) of grade ≥3 were neutropenia (64.3%), leukopenia (23.8%), diarrhea (19.0%), and fatigue (14.3%). Tucatinib increased AUC10-19 hours of palbociclib 1.7-fold, requiring palbociclib dose reduction from 125 to 75 mg daily. In 40 response-evaluable patients, mPFS was 8.4 months, with similar mPFS in non-CNS and CNS cohorts (10.0 months vs. 8.2 months; P = 0.9). Overall response rate was 44.5%, median duration of response was 13.9 months, and clinical benefit rate was 70.4%; 60% of patients were on treatment for ≥6 months, 25% for ≥1 year, and 10% for ≥2 years. In the CNS cohort, 26.6% of patients remained on study for ≥1 year.

CONCLUSIONS

TLP combination was safe and tolerable. AEs were expected and manageable with supportive therapy and dose reductions. TLP showed excellent efficacy for an all-oral chemotherapy-free regimen warranting further testing. See related commentary by Huppert and Rugo, p. 4993.

Safety and Tolerability of a Novel Anti-HER2 Antibody-Drug Conjugate (PF-06804103) in Patients with HER2-Expressing Solid Tumors: A Phase 1 Dose-Escalation Study

PF-06804103 is an anti-HER2 antibody-drug conjugate with auristatin payload. We evaluated its safety, tolerability, and antitumor activity in patients with advanced/unresectable or metastatic breast and gastric cancers. This multicenter, open-label, first-in-human, phase 1 study (NCT03284723) comprised dose escalation (P1) and dose expansion (P2). In P1, adults with HER2+ breast or gastric cancer received PF-06804103 0.15-5.0 mg/kg intravenously once/21 days (Q3W); in P2, patients with HER2+ or HER2-low (IHC 1+ or IHC 2+/ISH-) breast cancer received 3.0 or 4.0 mg/kg Q3W. The primary endpoints were dose-limiting toxicities (DLT) and safety (P1), and objective response rate (ORR) assessed using RECIST v1.1 (P2). Ninety-three patients enrolled in P1 (n = 47: HER2+ gastric cancer = 22, HER2+ breast cancer = 25) and P2 [n = 46: HER2+ breast cancer = 19, hormone receptor (HR)+ HER2-low breast cancer = 27] received PF-06804103. Four patients (3.0- and 4.0-mg/kg groups, n = 2 each) had DLTs (mostly Grade 3). Safety and efficacy results showed a dose-response relationship. Adverse events (AE) leading to treatment discontinuation (44/93, 47.3%) included neuropathy (11/93, 11.8%), skin toxicity (9/93, 9.7%), myalgia (5/93, 5.4%), keratitis (3/93, 3.2%), and arthralgia (2/93, 2.2%). Two (2/79, 2.5%) patients (P1, 4.0- and 5.0-mg/kg groups, n = 1 each) achieved complete response; 21 (21/79, 26.6%) achieved partial response. In P2, ORR was higher in HER2+ compared with HR+ HER2-low breast cancer [3.0 mg/kg: 16.7% (2/12) vs. 10.0% (1/10); 4.0 mg/kg: 47.4% (9/19) vs. 27.3% (3/11)]. PF-06804103 demonstrated antitumor activity; however, AEs led to discontinuation in 47.3% of patients. Safety and efficacy were dose-dependent.

Transcranial Magnetic Stimulation for the Treatment of Chemo Brain

This pilot feasibility study aimed to evaluate the effects of transcranial magnetic stimulation (TMS) on chemotherapy-related cognitive impairment (CRCI), and we report here on the first patient.

BACKGROUND

Deleterious cognitive changes due to chemotherapy or CRCI are commonly referred to as "chemo brain". With the increasing survival of cancer patients, this poorly understood and inadequately treated condition will likewise have an increasing toll on individuals and society. Since there is no approved treatment for chemo brain, we have initiated a therapeutic trial using transcranial magnetic stimulation (TMS), a non-invasive brain stimulation technique approved in many countries for the treatment of neurologic and psychiatric conditions like migraine and depression.

CASE PRESENTATION

A 58-year-old woman, diagnosed 7 years prior with left breast cancer, underwent partial mastectomy with sentinel lymph node biopsy. She then received four cycles of adjuvant chemotherapy followed by radiation therapy. Afterwards, she was on tamoxifen for 4 years and then switched to aromatase inhibitors. The patient's CRCI started during chemotherapy and severely impaired her quality of life for an additional two years. In the third year after chemotherapy, the CRCI partially cleared to stabilize to the level at the time of presentation for this trial. The patient continues to have memory difficulties and decreased concentration, which makes multi-tasking very difficult to impossible. She is reliant on memory aids at work and at home. The participant underwent 10 consecutive sessions of TMS during weekdays for 2 weeks. Stimulation was directed to the left dorsolateral prefrontal cortex. After TMS, the participant significantly improved in memory function on neuropsychological testing. While she reported no subjective differences in concentration or memory, she did report an improvement in her sleep. Functional magnetic resonance imaging of the brain before and after TMS showed increased resting-state functional connectivity between the stimulation site and several brain regions. Remarkably, after 6 years of chemo brain and remaining in the same position at work due to her inability to concentrate and multi-task, she applied for and received a promotion 5-6 months after her TMS treatments.

CONCLUSIONS

This first patient in the phase 1 clinical trial testing of TMS for the treatment of "chemo brain" provided important lessons for feasibility and insights into mechanisms of potential benefit.

Nuclear epidermal growth factor receptor as a therapeutic target

Epidermal growth factor receptor (EGFR) is one of the most well-studied oncogenes with roles in proliferation, growth, metastasis, and therapeutic resistance. This intense study has led to the development of a range of targeted therapeutics including small-molecule tyrosine kinase inhibitors (TKIs), monoclonal antibodies, and nanobodies. These drugs are excellent at blocking the activation and kinase function of wild-type EGFR (wtEGFR) and several common EGFR mutants. These drugs have significantly improved outcomes for patients with cancers including head and neck, glioblastoma, colorectal, and non-small cell lung cancer (NSCLC). However, therapeutic resistance is often seen, resulting from acquired mutations or activation of compensatory signaling pathways. Additionally, these therapies are ineffective in tumors where EGFR is found predominantly in the nucleus, as can be found in triple negative breast cancer (TNBC). In TNBC, EGFR is subjected to alternative trafficking which drives the nuclear localization of the receptor. In the nucleus, EGFR interacts with several proteins to activate transcription, DNA repair, migration, and chemoresistance. Nuclear EGFR (nEGFR) correlates with metastatic disease and worse patient prognosis yet targeting its nuclear localization has proved difficult. This review provides an overview of current EGFR-targeted therapies and novel peptide-based therapies that block nEGFR, as well as their clinical applications and potential for use in oncology.

Dose escalation and expansion cohorts in patients with advanced breast cancer in a Phase I study of the CDK7-inhibitor samuraciclib

Samuraciclib is a selective oral CDK7-inhibitor. A multi-modular, open-label Phase I study to evaluate safety and tolerability of samuraciclib in patients with advanced malignancies was designed (ClinicalTrials.gov: NCT03363893). Here we report results from dose escalation and 2 expansion cohorts: Module 1A dose escalation with paired biopsy cohort in advanced solid tumor patients, Module 1B-1 triple negative breast cancer (TNBC) monotherapy expansion, and Module 2A fulvestrant combination in HR+/HER2- breast cancer patients post-CDK4/6-inhibitor. Core study primary endpoints are safety and tolerability, and secondary endpoints are pharmacokinetics (PK), pharmacodynamic (PD) activity, and anti-tumor activity. Common adverse events are low grade nausea, vomiting, and diarrhea. Maximum tolerated dose is 360 mg once daily. PK demonstrates dose proportionality (120 mg-480 mg), a half-life of approximately 75 hours, and no fulvestrant interaction. In dose escalation, one partial response (PR) is identified with disease control rate of 53% (19/36) and reduction of phosphorylated RNA polymerase II, a substrate of CDK7, in circulating lymphocytes and tumor tissue. In TNBC expansion, one PR (duration 337 days) and clinical benefit rate at 24 weeks (CBR) of 20.0% (4/20) is achieved. In combination with fulvestrant, 3 patients achieve PR with CBR 36.0% (9/25); in patients without detectable TP53-mutation CBR is 47.4% (9/19). In this study, samuraciclib exhibits tolerable safety and PK is supportive of once-daily oral administration. Clinical activity in TNBC and HR+/HER2-breast cancer post-CDK4/6-inhibitor settings warrants further evaluation.

Oxylipins as Biomarkers for Aromatase Inhibitor-Induced Arthralgia (AIA) in Breast Cancer Patients

Aromatase inhibitor-induced arthralgia (AIA) presents a major problem for patients with breast cancer but is poorly understood. This prospective study explored the inflammatory metabolomic changes in the development of AIA. This single-arm, prospective clinical trial enrolled 28 postmenopausal women with early-stage (0-3) ER+ breast cancer starting adjuvant anastrozole. Patients completed the Breast Cancer Prevention Trial (BCPT) Symptom Checklist and the Western Ontario and McMaster Universities Arthritis Index (WOMAC) at 0, 3, and 6 months. The plasma levels of four polyunsaturated fatty acids (PUFAs) and 48 oxylipins were quantified at each timepoint. The subscores for WOMAC-pain and stiffness as well as BCPT-total, hot flash, and musculoskeletal pain significantly increased from baseline to 6 months (all p < 0.05). PUFA and oxylipin levels were stable over time. The baseline levels of 8-HETE were positively associated with worsening BCPT-total, BCPT-hot flash, BCPT-musculoskeletal pain, WOMAC-pain, and WOMAC- stiffness at 6 months (all p < 0.05). Both 9-HOTrE and 13(S)-HOTrE were related to worsening hot flash, and 5-HETE was related to worsening stiffness (all p < 0.05). This is the first study to prospectively characterize oxylipin and PUFA levels in patients with breast cancer starting adjuvant anastrozole. The oxylipin 8-HETE should be investigated further as a potential biomarker for AIA.

Abstract P1-05-04: Physician Practice Patterns of Breast Imaging After Treatment: Survey of Real-World Practice

Introduction: Mammography is the cornerstone of breast cancer screening, diagnosis, and surveillance. After definitive treatment for breast cancer, mammograms are continued for surveillance. The current recommendations regarding surveillance after definitive treatment (surgery and radiation) lack consensus amongst various societies. There are no clear guidelines in regards to the type of mammogram recommended: diagnostic or screening mammogram or if a diagnostic mammogram is used, when to return to routine screening protocols. Current practice patterns are driven by physician’s preference. We conducted a survey to evaluate physicians’ preferences in ordering breast imaging post- breast cancer diagnosis and treatment. Methods: This survey was approved by University of Arizona institutional review board. This survey was conducted through American Society of Clinical Oncology (ASCO) voluntary opt-in Research Survey Pool (RSP). ASCO sent out this survey to 1000 randomly selected members between 10/19/2021-11/22/2021. Weekly reminders to participate were sent through the ASCO RSP for 5 weeks. Participants clicked the link to the survey platform where upon consent they completed the survey. Results: The survey was completed by 244 healthcare professionals through the ASCO RSP. Most respondents were physicians (n=228), primarily medical oncologists (n=174) and practiced in an academic environment in the United States (n=132). After definitive treatment, majority (58%) ordered first imaging at 6 months post-surgery/radiation, and it was primarily a diagnostic mammogram (68%). Interestingly, for patients at age 80 or above, screening mammogram was used for surveillance after definitive treatment by most respondents (59%). After first post-surgery/radiation mammogram there is an almost even spilt (50%) on continuing with diagnostic versus screening mammograms for follow up. Of those who order diagnostic mammograms, majority (38%) do it for 3-5 years with an additional 30% continuing it beyond 5 years. Almost 65% of respondents reported they do not stop screening mammograms at any age for patients with a history of early-stage breast cancer as long as they are healthy. Conclusions: The practice patterns of healthcare professionals as it relates to the type and frequency of breast imaging varies significantly. Despite having the same imaging quality there is a significant difference in the cost of screening and diagnostic mammograms. In addition, in clinical practice, most routine screening care is covered by insurances without co-pays or out of pocket costs for patients. Diagnostic imaging does not fall under routine screening care and frequently requires out of pocket expenses for patients. As insurance companies start to decline certain imaging modalities used for cancer detection due to lack of data supporting the use of these expensive studies, specific imaging guidelines for follow up in post-treatment setting for patients with breast cancer are needed.

Citation Format: Meredith Whittaker, Kiah Farr, Preethika Potluri, Nova Foster, Jennifer Erdrich, Jennifer Segar, Sima Ehsani, Sao Jiralerspong, Denise Roe, Pavani Chalasani. Physician Practice Patterns of Breast Imaging After Treatment: Survey of Real-World Practice [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P1-05-04.

Abstract P4-01-16: High levels of RSK2 in breast cancer patients is associated with longer PFS in patients treated with PMD-026, a first in class RSK inhibitor

Background: Breast cancer (BC) is the most common malignancy in women and metastatic triple negative breast cancer (mTNBC) remains one of the most difficult to treat cancers with few targeted treatment options. RSK is recognized as a critical signaling component in the MAPK/PDK-1 pathways, is an important driver for BC and a signature of poor prognosis. PMD-026 is the first RSK inhibitor to enter clinical trials and is being developed alongside an immunohistochemistry (IHC) companion diagnostic to select patients with increased activated RSK2 in tumor tissue. A Phase 1/1b trial of PMD-026 in patients with metastatic breast cancer (mBC) or metastatic triple negative breast cancer (mTNBC) established safety at a dose of 200 mg Q12h. Efficacy signals in patients with heavily pretreated mBC/mTNBC are explored in this analysis along with evaluation of the effect of food (FE) on systemic exposure to treatment. Methods: PMD-026 was administered to 41 patients as a single agent in this phase 1/1b open-label study, with 30 patients evaluable for efficacy. Exploratory objectives were to identify subgroups of patients who may optimally benefit from PMD-026. Subgroup analysis of patients included 1) comparing BC patients who received ≤5 vs &gt;5 prior therapies; 2) comparing TNBC patients (de novo vs secondary subtypes)1, and 3) comparing patients with low RSK2 H-scores (&lt; 180) vs high (≥180). In addition, PMD 026 PK was evaluated at the 200 mg Q12h dose and a FE sub-study enrolled 12 patients administered a single 200 mg dose. Results: PMD-026 monotherapy was generally well-tolerated in the 41 mBC patients who were enrolled and treated. Kaplan-Meier PFS analysis of 30 evaluable BC patients who were dosed with PMD-026 showed that patients with less prior therapy (≤5) did significantly better (HR, 0.19; 95% CI [0.06–0.52], p=0.0014) than those with &gt; 5 prior therapies. Subgroup analysis of PFS in those with TNBC demonstrated that de novo TNBC (n=17) had longer time on treatment with PMD-026 compared with secondary TNBC (n=9) (HR, 0.31; 95% CI [0.10-0.99], p=0.0476). In those with de novo TNBC with ≤5 prior therapies, a high RSK2 H-score was associated with significantly longer PFS at the RP2D (4.2 vs 1.3 months, HR, 0.17; 95% CI [0.03-0.80], p=0.0254) than patients with a low RSK2 H-score. In patients with CDK4/6 resistant HR+ BC (n=3), PFS was 5.2 (RSK2 high) vs 1.3 months (RSK2 low). Stable disease was observed in 53% (9/17) of patients with de novo TNBC and in 67% (6/9) of de novo TNBC patients with high RSK2. Tumor necrosis or target lesion reduction (&lt; 30%) was observed in 17% of patients (5/30), all of whom had high RSK2 expression. In the FE sub-study, increased interpatient variability in PMD-026 Cmax and Tmax but not AUC, was observed when administered with food, favored dosing in a fasted state, which is consistent with the pH dependent solubility of PMD-026. Notably, all FE patients (12/12) achieved the target concentration of 1µM (IC90 in preclinical studies) within 4 hours when PMD-026 was taken without food. At the RP2D, PMD-026 taken without food showed relatively consistent exposure among patients over 24 hr timeframe. Conclusions: These findings demonstrate that in patients treated with PMD-026 who had received &lt; 5 prior treatment regimens, had de novo TNBC or CDK4/6 refractory HR+ disease and had high RSK2 scores had longer PFS. Overall, PMD-026 is a well-tolerated, orally available RSK2 inhibitor that will be evaluated further for efficacy in TNBC and CDK4/6i refractory HR+ mBC, in a trial that will prospectively enroll patients based on RSK2 activation as defined by the RSK2 IHC H-scores. Clinical trial information: NCT04115306. 1 Patients diagnosed and treated for TNBC from their initial diagnosis (de novo TNBC) vs patients previously treated for hormone receptor positive (HR+) or human epidermal growth factor 2 receptor positive (HER2+) BC, but became HR or HER2 negative (secondary TNBC)

Citation Format: Judy S. Wang, Muralidhar Beeram, Pavani Chalasani, Lida Mina, Rebecca A. Shatsky, Sara Hurvitz, Meghna S. Trivedi, Robert Wesolowski, Hyo S. Han, Amita Patnaik, Shakeela Bahadur, My-my Huynh, Aarthi Jayanthan, Gerrit Los, Sandra E. Dunn, Andrew Dorr. High levels of RSK2 in breast cancer patients is associated with longer PFS in patients treated with PMD-026, a first in class RSK inhibitor [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P4-01-16.

Social Determinants of Health and Symptom Burden During Cancer Treatment

BACKGROUND

Cancer survivors (defined as individuals from diagnosis to the end of life) in treatment experience multiple physical and psychological symptoms (e.g., fatigue, pain, depression, anxiety, disturbed sleep) that influence their well-being and treatment outcomes. Underrepresented cancer survivors may disproportionately experience greater symptom burden (number of symptoms, symptom severity, depression, anxiety).

OBJECTIVES

The aim of this study was to examine the relationships of social determinants of health, including age, ethnicity, education, income and whether income meets the survivor's needs, neighborhood (rural vs. urban), access to healthcare (e.g., insurance), and social isolation, with symptom burden in cancer survivors.

METHODS

This secondary analysis included baseline data from 400 cancer survivors of solid tumor cancers undergoing chemotherapy or targeted therapy who participated in a larger randomized trial of symptom management interventions. Symptom burden was measured by the Center for Epidemiological Studies-Depression scale for depression and Patient-Reported Outcomes Measurement Information System scores for anxiety and social isolation, summed severity index of 16 symptoms from the General Symptom Distress Scale, and the total number of symptoms. Self-reported comorbid conditions were measured using the Bayliss tool. General linear models were used to relate symptom measures (one at a time) to age, number of comorbid conditions, level of education, marital status, income meeting needs, and size of metropolitan neighborhood. Additional covariates included site of cancer, its treatment, and whether the cancer was metastatic.

RESULTS

Non-Hispanic White survivors ( n = 191) were older and had more comorbid conditions, a higher proportion of metastatic cancers, and higher levels of education and income compared with Hispanic survivors ( n = 168) and non-Hispanic survivors of other races ( n = 41). Compared with the other two groups, Hispanic survivors had the lowest rate of health insurance availability, and non-Hispanic survivors of other races had the lowest social isolation. Age, number of comorbid conditions, and social isolation were significantly associated with number of symptoms, symptom severity, and depression. Age and social isolation were associated with anxiety. In addition, the symptom severity of non-Hispanic White survivors was lower than that of Hispanic survivors and non-Hispanic survivors of other races.

DISCUSSION

These findings highlight the health disparities in symptom burden experienced among cancer survivors when considering their social determinants of health. Assessing these may help clinicians address health disparities in cancer care.

Abstract P4-04-02: Evaluation of Dronabinol to Decrease Opioid Use for Cancer- Induced Bone Pain

Purpose Bone metastases (BM) from breast cancer cause significant complications including pain, hypercalcemia, spinal cord compression, and pathologic fractures, collectively referred to as skeletal related events (SREs). Of all SREs, bone pain impacts the quality of life (QOL) most significantly. Cancer- induced bone pain (CIBP) is difficult to treat with limited treatment options and requires a multimodal approach. Management of CIBP is primarily by opioids which have notable side effects like sedation, constipation, and concern for addiction. In addition, pre-clinical evidence suggests that opioids accelerate bone loss and increase risk of fractures. There is an unmet need for novel analgesic therapy interventions to optimize QOL for patients with BM from metastatic breast cancer. Preclinical studies have shown that the endogenous cannabinoid (CB) system is involved in pain modulation, bone regulation, immunity, and restraint of cancer pathogenesis. CB2 receptor activation has been shown to inhibit proinflammatory cytokines/chemokines in pre-clinical models. Treatment with selective CB2 agonist in mice with BM led to significant antinociception, decreased cancer-induced bone degradation, and reduced side effects of morphine. In addition to alleviating pain, CB2 agonists were shown to enhance bone growth/strength in these mice. Based on this pre-clinical data, we hypothesized that the addition of a CB2 agonist will improve pain symptoms and decrease opioid requirement in patients with bone metastases from breast cancer. We proceeded to conduct a pilot study by repurposing a clinically approved CB2/CB1 agonist, dronabinol. Methods We conducted a prospective, single site study among patients with BM from breast cancer at our center (NCT03661892). Patients had to have been on opioids for CIBP for at least 4 weeks and not using marijuana or CBD products. Patients were treated with 10mg dronabinol BID for 8 weeks. Our primary objective was to determine the proportion who decrease their opioid use by ≥ 20%. The null hypothesis value was 5% of women would have a 20% decrease. With 14 participants, we could detect an increase from 5% to 29% (n=4) with 80% statistical power using a one-sided alpha level of 0.05. Participants completed Brief Pain Inventory and the European Organization for Research and Treatment of Cancer quality of life questionnaires pre and post treatment. Results Twenty participants consented with 14 patients completing the study and evaluable for primary analysis. No patients received any palliative radiation therapy or other therapies for bone pain within 3 months prior to enrollment to this study. Four patients decreased their opioid use by ≥ 20% meeting the primary objective. Patients reported significant improvement in pain severity, interference scores, quality of life and insomnia based on the questionnaires. There were no grade 4 side effects and only 1 patient had grade 3 adverse event (dizziness) related to study drug. Of the 14 patients who completed the study, 9 desired to continue dronabinol therapy after completion. Conclusion Our pilot study shows that the addition of dronabinol resulted in decreased opioid requirements for CIBP in patients with metastatic breast cancer. Patient-reported outcomes also demonstrated improved pain and QOL with the addition of dronabinol. While we did not see any significant AEs tolerability may be of concern due to CB1 psychoactive effects. Our results are promising and warrant further investigation into evaluating CB2 agonists for improved pain control from CIBP and to decrease opioid use.

Citation Format: Jennifer Segar, Kiah Farr, Mary Junak, Denise Roe, Sima Ehsani, Sao Jiralerspong, Ibrahim Mohab, Todd Vanderah, Pavani Chalasani. Evaluation of Dronabinol to Decrease Opioid Use for Cancer- Induced Bone Pain [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P4-04-02.

A Sequential Multiple Assignment Randomized Trial of Symptom Management After Chemotherapy

CONTEXT

Many cancer survivors experience a lingering symptom burden after chemotherapy.

OBJECTIVES

In this sequential multiple assignment randomized trial, we tested optimal sequencing of two evidence-based interventions for symptom management.

METHODS

Survivors of solid tumors (N = 451) were interviewed at baseline and stratified as high or low need for symptom management based on comorbidity and depressive symptoms. High need survivors were randomized initially to the 12-week Symptom Management and Survivorship Handbook (SMSH, N = 282) or 12-week SMSH with eight weeks of Telephone Interpersonal Counseling (TIPC, N = 93) added during weeks one to eight. After four weeks of the SMSH alone, non-responders on depression were re-randomized to continue with SMSH alone (N = 30) or add TIPC (N = 31). Severity of depression and summed severity index of 17 other symptoms over weeks one to13 were compared between randomized groups and among three dynamic treatment regimes (DTRs): 1) SMSH for 12 weeks; 2) SMSH for 12 weeks with eight weeks of TIPC from week one; 3) SMSH for four weeks followed by SMSH+TIPC for eight weeks if no response to the SMSH alone on depression at week four.

RESULTS

There were no main effects for randomized arms or DTRs, but there was a significant interaction of trial arm with baseline depression favoring SMSH alone during weeks one to four in the first randomization and SMSH+TIPC in the second randomization.

CONCLUSION

The SMSH may represent a simple effective option for symptom management, adding TIPC only when there is no response to SMSH alone for people with elevated depression and multiple co-morbidities.

Abstract P065: Effects of metformin on breast tissue inflammation in premenopausal women with components of metabolic syndrome

Background: Obesity, with increasing worldwide prevalence, is associated with increased breast cancer burden. The association is attributed to multiple metabolic disturbances including chronic inflammation due to dysfunctional adipose tissue. Features of local breast adipose tissue inflammation such as macrophage infiltration and an enriched pro-inflammatory gene signature were recently reported in mouse models of obesity and in women with high adiposity or metabolic disorders. Strategies that can reduce obesity-induced chronic inflammation may lead to reduction of breast cancer risk. Metformin, a widely used anti-diabetic drug, exerts favorable effects on multiple metabolic disturbances. This study aims to evaluate the clinical effects of metformin on breast tissue inflammation. Methods: Macrophage infiltration and polarization were determined in breast core needle biopsies collected at baseline and 6 months after agent intervention from a Phase II randomized, double-blind, placebo-controlled trial of metformin in premenopausal women with components of metabolic syndrome. Macrophage infiltration was assessed using a pan macrophage marker (CD68) by immunohistochemistry (IHC). M1 and M2 macrophages were assessed using CD40 and CD206 surface markers, respectively, by IHC. The primary endpoint is the change in macrophage density in breast adipose tissue. Secondary endpoints include the change in macrophage density in breast stroma and epithelium tissues, the proportion of M1 (pro-inflammatory) and M2 (anti-inflammatory) macrophages in breast adipose, stroma, and epithelium tissues. Results: Baseline biopsies from 76 participants (40 in the metformin arm and 36 in the placebo arm) were available for CD68 analysis. The baseline CD68 density was 22.48 ± 3.25, 67.26 ± 9.68, 418.81± 71.02 (mean±SE) per mm2 in breast adipose, stroma, and epithelium tissues, respectively. Biopsies from 71 participants (34 in the metformin arm and 37 in the placebo arm) were available for CD68 analysis at 6 months. Comparing to placebo, metformin intervention led to a significant reduction in CD68 density in breast adipose tissue (p = 0.01) but did not change the CD68 density in breast epithelium and stroma tissues. Conclusion: Metformin intervention resulted in favorable changes in macrophage infiltration in breast adipose tissue in premenopausal women with component of metabolic syndrome. Studies are ongoing to evaluate the effects of metformin on macrophage polarization.

Citation Format: Liane E. Pinto, Sara Centuori, Jose Guillen-Rodriguez, Denise J. Roe, Edgar Tapia, Pavani Chalasani, H-H. Sherry Chow. Effects of metformin on breast tissue inflammation in premenopausal women with components of metabolic syndrome. [abstract]. In: Proceedings of the AACR Special Conference: Precision Prevention, Early Detection, and Interception of Cancer; 2022 Nov 17-19; Austin, TX. Philadelphia (PA): AACR; Can Prev Res 2023;16(1 Suppl): Abstract nr P065.

Camptothesome Potentiates PD-L1 Immune Checkpoint Blockade for Improved Metastatic Triple-Negative Breast Cancer Immunochemotherapy

In this study, we focus on investigating the therapeutic effects of camptothesome on treating metastatic triple-negative breast cancer (TNBC). We elucidate that camptothesome elicited stronger immunogenic cell death (ICD) compared to free camptothecin (CPT) and Onivyde in 4T1 TNBC cells. In addition, camptothesome is mainly internalized by the 4T1 and MDA-MB-231 cells through clathrin-mediated endocytosis based on the results of flow cytometry. Through real-time Lago optical imaging, camptothesome shows excellent tumor-targeting efficiency in orthotopic TNBC tumors. We demonstrate that camptothesome can upregulate programmed death-ligand 1 (PD-L1) in 4T1 tumors in an interferon gamma (IFN-γ)-dependent manner. Furthermore, the anti-TNBC efficacy studies reveal that camptothesome is superior to Onivyde and markedly potentiates PD-L1 immune checkpoint blockade therapy with complete lung metastasis remission in an orthotopic 4T1-Luc2 tumor model. This combination therapy eliciting robust cytotoxic T lymphocytes (CTL) response via boosting tumor-infiltrating cluster of differentiation 8 (CD8), calreticulin (CRT), high mobility group box 1 protein (HMGB-1), low-density lipoprotein receptor-related protein 1 (LRP1), IFN-γ, and granzyme B. Our work corroborates the promise of camptothesome in favorably modulating tumor immune microenvironment via inducing ICD to fortify the PD-L1 checkpoint blockade therapy for improved treatment of intractable TNBC.

Investigating keratinocyte growth factor hair serum for the prevention of chemotherapy-induced alopecia

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Background: Chemotherapy induced alopecia (CIA) is known to have a significant psychological and quality of life impact, mainly in women. While cold caps have been shown to decrease CIA, expense, availability, and extension of treatment durations are barriers for routine clinical use. Keratinocyte Growth Factor (KGF) has been shown to have cytoprotective effects on human keratinocytes in vitro and reduce apoptosis in human hair follicles. Based on this data, we hypothesized that KGF-Hair serum (KGF-HS) will prevent CIA in women undergoing chemotherapy as treatment for breast cancer. Methods: We designed a Simon 2-stage prospective study to test our hypothesis. Study was approved by our institutional review board and registered on clinicaltrials.gov (NCT04554732). In part 1 we planned to enroll 20 patients into a single arm. If ≥ 4 responses are noted, we proposed to initiate part 2: randomized double-blind placebo-controlled study. Patients with early-stage breast cancer (ESBC) who were scheduled to get at least 4 cycles of anthracycline or taxane based chemotherapy were included. Patients with inflammatory scalp conditions, hair loss disorder, scalp disorders were excluded. The primary endpoint was successful hair preservation using the Common Terminology Criteria for Adverse Events 4.0 scale at the end of 4 cycles of chemotherapy. Secondary end points included wig use and scores on the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire–Core 30, Hospital Anxiety and Depression Scale, and a summary scale of the Body Image Scale. Results: Twenty patients completed part 1 of the study and were evaluable for primary endpoint. Mean age was 60 years and 70% were treated with taxane based chemotherapy. Successful hair preservation was noted in 0 of 20 women. Mean duration of treatment with KGF-HS was 4.6wks (range 2-10 weeks) before women came off study due to grade 2 hair loss. There were no statistically significant differences in changes in any of the scales of quality of life from baseline to end of treatment. There were only 2 grade 1 events (1 rash and 1 itching) reported which resolved after coming off the KGF-HS. There were no serious adverse device events. Conclusions: Among women with early-stage breast cancer receiving chemotherapy with a taxane, anthracycline, or both, using KGF-HS did not prevent CIA. Further research is needed to investigated other novel topical options to prevent CIA. Clinical trial information: NCT04554732.

Use of scheduled and unscheduled health services by cancer survivors and their caregivers

PURPOSE

The purpose was to determine predictors of scheduled and unscheduled health services use by cancer survivors undergoing treatment and their informal caregivers.

METHODS

English- or Spanish-speaking adult cancer survivors undergoing chemotherapy or targeted therapy for a solid tumor cancer identified a caregiver (N = 380 dyads). Health services use over 2 months was self-reported by survivors and caregivers. Logistic regression models were used to relate the likelihood of service use (hospitalizations, emergency department [ED] or urgent care visits, primary care, specialty care) to social determinants of health (age, sex, ethnicity, level of education, availability of health insurance), and number of comorbid conditions. Co-habitation with the other member of the dyad and other member's health services use were considered as additional explanatory variables.

RESULTS

Number of comorbid conditions was predictive of the likelihood of scheduled health services use, both primary care and specialty care among caregivers, and primary care among survivors. Greater probability of specialty care use was associated with a higher level of education among survivors. Younger age and availability of health insurance were associated with greater unscheduled health services use (hospitalizations among survivors and urgent care or ED visits among caregivers). Unscheduled health services use of one member of the dyad was predictive of use by the other.

CONCLUSIONS

These findings inform efforts to optimize health care use by encouraging greater use of scheduled and less use of unscheduled health services. These educational efforts need to be directed especially at younger survivors and caregivers.

Real-world data on outcomes using taxane, trastuzumab, and pertuzumab (THP) in patients with early stage HER2+ breast cancer

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Background: In HER2+ early breast cancer, dual HER2 targeted combination of trastuzumab and pertuzumab with chemotherapy achieved higher rates of pathologic complete response (pCR) and improved long term outcomes. However, the optimal chemotherapy backbone is still under investigation. While neoadjuvant taxane in combination with trastuzumab and pertuzumab (THP) has been investigated in NEOSPHERE, patients received anthracycline-based regimen in the adjuvant setting. We report real-world data on long-term patient outcomes after neoadjuvant THP. Methods: An IRB-approved retrospective chart review at 2 academic centers was conducted using EMR to identify women with stage I-III HER2+ breast cancer who exclusively received neoadjuvant THP between 2013-2020. Clinicopathological characteristics and follow up information were extracted from surgical pathology and medical records. Results: 71 patients met criteria (median, 55 years). At presentation, 56 (79%) patients had stage II - III disease and 45 (63%) were lymph node negative. The majority of tumors were ER+ (43 patients, 61%) and received paclitaxel (46 patients, 65%) as their taxane backbone. pCR was achieved in 40 (56%) patients (Table); 38 (95%) continued with adjuvant HER2 therapy alone; 1 received adjuvant endocrine therapy only and 1 received no further treatment. Of the 31 (44%) patients without pCR, 9 received additional adjuvant chemotherapy in addition to HER2 directed therapy while 18 continued with HER2 therapy alone. During the follow-up period (median 34.7 mo, range 6.8-98.9 mo), 3 patients with lymph node positive disease on presentation had disease relapse. Two of the patients with pCR had local recurrence and one without pCR had distant metastasis (brain, lung). The 2 patients with local recurrence were successfully treated with salvage therapy and remain in remission. The patient with metastatic disease remains alive and on treatment. Conclusions: We showed that a real world HER2+ patient population treated with neoadjuvant THP achieved pCR rates consistent with what has been previously reported. In addition, with a median follow up of ̃ 3 years, only 3 patients had relapse supporting the utility of THP as potential de-escalation treatment in the neoadjuvant setting. Ongoing prospective trials, like NCT03716180, will further confirm the efficacy of this regimen in a prospective setting.[Table: see text]

Abstract P1-10-02: Effect of metformin on metabolic markers associated with breast cancer risk in a phase II clinical trial in overweight/obese premenopausal women

Background: The increasing rate of obesity in the United States is accompanied by serious health concerns. Obesity increases breast cancer burden and is associated with increased risk of triple-negative breast cancer in premenopausal women and overall poor prognosis in breast cancer patients. There is a need for intervention strategies aiming to reduce obesity-associated dysregulation to attenuate breast cancer risk.Methods: We conducted a Phase II, double-blind, randomized, placebo-controlled clinical trial in overweight/obese premenopausal women with elements of metabolic syndrome to assess the potential of metformin to reduce obesity-associated breast cancer risk. Study participants received metformin (850 mg BID, n = 76) or placebo (n = 75) for 12 months. Fasting blood samples were collected at baseline, 6-months and 12-months from each participant. We analyzed the effects of metformin on circulating levels of insulin/IGF axis, adipokines, and neutrophil-to-lymphocyte ratio in samples collected from this trial. Serum concentrations of insulin, IGF-1, IGFBP-3, leptin and high-molecular weight adiponectin were measured using ELISA immunoassays. Results: The study population included 151 women and had a mean age of 39.5 years, mean body mass index (BMI) was 37.8 and study participants had a large waist and at least one other component of metabolic syndrome. Metformin treatment did not result in significant changes in members of the insulin/IGF axis compared to the placebo group, however, limiting the analysis to participants with detectable metformin in the blood serum resulted in favorable changes in insulin (p=0.0215), HOMA-IR (p&lt;0.001) and a significant increase in IGFBP-3 (p=0.0176) in the metformin group after the intervention. We observed significant decreases in leptin (p=0.0018) and the leptin-to-adiponectin ratio (p=0.0036) in the metformin arm longitudinally. Additionally, we observed a significant reduction in the neutrophil-to-lymphocyte ratio (NLR), a systemic inflammation marker, in the metformin group compared to the placebo group (p=0.0170). Conclusions: We conclude that metformin led to favorable changes in metabolic markers associated with breast cancer risk in the metformin treated participants, however, the changes were not significantly different from the placebo group. The NLR was significantly reduced after metformin intervention compared to the placebo group. More research is needed to understand the effects of metformin on the insulin/IGF axis and adipokines in overweight/obese premenopausal women.

Citation Format: Edgar Tapia, Diana Villa-Guilen, Pavani Chalasani, Sara Centuori, Denise J. Roe, Jose Guillen, Catherine Cordova, Liane Pinto, Sherry Chow. Effect of metformin on metabolic markers associated with breast cancer risk in a phase II clinical trial in overweight/obese premenopausal women [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P1-10-02.

Abstract P1-17-02: ZN-c5, an oral selective estrogen receptor degrader (SERD), in women with advanced estrogen receptor-positive (ER+)/human epidermal growth factor receptor 2 negative (HER2-) breast cancer

Background: Hormone receptor+/HER2- breast cancer is the most common subtype of breast cancer. Resistance to endocrine therapy is a major clinical challenge. Although fulvestrant binds and degrades the ER and shows anti-tumor activity in patients with advanced breast cancer, intramuscular injection is inconvenient and precludes achievement of higher and potentially more efficacious exposure. ZN-c5 is a novel, orally bioavailable SERD with high potency and has demonstrated activity in estrogen-dependent tumor models. Methods: This Phase 1/2, open-label, multicenter study is evaluating the safety, pharmacokinetics and preliminary anti-tumor activity of ZN-c5 as monotherapy or in combination with palbociclib. In the Phase 1 portion evaluating ZN-c5 as monotherapy, participants were adult, post-menopausal (or receiving a gonadotropin-releasing hormone agonist) women with advanced adenocarcinoma of the breast, ER+/HER2- disease, and sensitive to endocrine therapy for metastatic disease (partial response [PR], complete response or stable disease [SD] lasting &gt; 6 months or disease recurrence after at least 24 months of adjuvant endocrine treatment). ZN-c5 was administered orally and continuously in 28-day cycles until disease progression or unacceptable toxicity. Dose escalation cohorts of subjects were enrolled at several dose levels of ZN-c5, based on a modified 3+3 design. Enrollment in the Phase 1 ZN-c5 monotherapy dose escalation and expansion has been completed and results are presented. Phase 1 testing of ZN-c5 in combination with palbociclib and Phase 2 testing in monotherapy are ongoing and will be presented at a future meeting. Results: In Phase 1 monotherapy, a total of 56 female subjects were enrolled to receive ZN-c5 at dose levels of 50 mg once daily (QD, n=16), 75 mg QD (n=3), 100 mg QD (n=3), 75 mg twice daily (BID, n=6), 150 mg QD (n=15), 150 mg BID (n=3), or 300 mg QD (n=10). Median age was 58.5 years (range, 38 - 89) and ECOG performance status was 0 (55%) or 1 (45%). Subjects had a median of 2 prior therapies for advanced/metastatic disease (range, 0 - 9), with a median of 2 prior hormonal-based therapies (range, 0 - 6) and a median of 0 prior chemotherapies (range, 0 - 3). Twenty-six subjects (46%) received prior fulvestrant and 38 (68%) received a prior CDK4/6 inhibitor. Twenty subjects (38%) had a baseline ESR1 mutation. The cut-off date for this analysis was 11 May 2021. There was no increase in severity of treatment-emergent adverse events (TEAEs) with increase in dose level. No dose-limiting toxicities were reported. The most common TEAEs were nausea (30%), fatigue (25%), and arthralgia (20%). Grade 3 TEAEs reported in &gt; 1 subject were gamma-glutamyltransferase (GGT) increased and hyponatremia (2 subjects each); no Grade 4 TEAEs were reported. Among treatment-related events, the most common were hot flushes and nausea (14% each); the only Grade 3 events were GGT increased and hypersensitivity in 1 subject each. ZN-c5 was rapidly absorbed, with a median Tmax of 2 to 4 hours. AUC and Cmax on Days 1 and 15 were less than dose proportional. No ZN-c5 accumulation after 15 days of dosing was observed. Confirmed PRs have been observed in 2 subjects (at 150 and 300 mg QD, respectively), and 14/45 (31%) evaluable subjects have experienced clinical benefit (PR or SD ≥ 24 weeks). Five of the 14 subjects with long SD received prior fulvestrant. Median progression-free survival (PFS) was 3.8 months (95% CI: 3.2, 5.3). Conclusions: In this first-in-human study, ZN-c5 monotherapy was well tolerated and showed clinical benefit, including confirmed PRs, in subjects with advanced ER+/HER2- breast cancer. These data warrant further evaluation of ZN-c5 as monotherapy and in combination with palbociclib.

Citation Format: Kevin Kalinksy, Vandana Abramson, Pavani Chalasani, Hannah M. Linden, Jasmina Alidzanovic, Rachel M. Layman, Živko Vranješ, Julie R. Nangia, Katherine D. Crew, Zoran Andric, Marijana Milovic-Kovacevic, Jasna Trifunovic, Jose Suarez, Matt Suster, Mieke Ptaszynski, Joanne Mortimer. ZN-c5, an oral selective estrogen receptor degrader (SERD), in women with advanced estrogen receptor-positive (ER+)/human epidermal growth factor receptor 2 negative (HER2-) breast cancer [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P1-17-02.

Abstract P1-10-05: Evidence that body mass index modifies breast tissue collagen peptide response pattern to treatment with the non-steroidal anti-inflammatory drug sulindac

Background. In observational studies, regular use of non-steroidal anti-inflammatory drugs (NSAIDs) is associated with reduced breast cancer risk and disease recurrence with evidence that the benefit is greater in overweight/obese women. This parallels findings that obesity is associated with an increase in proinflammatory processes with possible effects on the breast stroma and extracellular matrix. Methods. To assess if body mass index (BMI kg/m2) alters breast tissue response to NSAIDs, we conducted exploratory analyses of change in breast tissue collagen-associated peptides following 6 months of treatment with the NSAID sulindac (150 mg bid) by BMI category: normal (18.5-24.9 n=6), overweight (25-29.9 n=14) and obese (≥30 n=11). Samples for this study were non-cancer core needle breast biopsies from postmenopausal women with a history of hormone receptor positive breast cancer enrolled to study sulindac effect on breast tissue biomarkers. At completion, 36 of 50 patients underwent baseline biopsy and 31 had sufficient tissue for paired analyses. Tissue collagen-associated peptides were studied using whole slide tissue imaging mass spectrometry proteomics. Individual peptide signals were normalized to total ion current and mean peak intensity per area across the entire biological specimen were used to generate a score per patient. Change in stroma peptides was evaluated by BMI status using the Wilcoxon matched pairs signed rank test. Unsupervised hierarchical clustering and heatmap visualization were used to assess differential expression of the peaks. Results. Approximately, 550 peptide peaks were found by targeted collagen tissue imaging proteomics. Striking differences in response to sulindac were observed by BMI. In overweight patients, 6 peptides related to COL1A1, COL6A1, COL6A3 and VIM on database matching differed significantly before and after sulindac treatment. Three were also altered in obese women. Two of the peptides overlapped 10 peptide changes identified in unstratified analyses reported in a separate submitted abstract on the main effect of sulindac on tissue collagen. Interestingly, these peptides were not altered in patients with normal BMI. In addition, on study 15 patients experienced a decrease in BMI and 12 experienced an increase. Two collagen peptides showed inverse relationships dependent on change in BMI status during the study. Conclusion. Six-month treatment with the non-selective NSAID sulindac was associated with changes in collagen-associated peptide differently by BMI status and by weight change. Our findings are most consistent with changes in post-translational hydroxylated proline modifications of collagen variation in the triple helical region. Ongoing work may provide insights on inflammation/adiposity-associated inflammation and effects on breast tissue collagen.

Citation Format: Denys Rujchanarong, Peggi M. Angel, Alison Stopeck, Christina Preece, Pavani Chalasani, Patricia A. Thompson. Evidence that body mass index modifies breast tissue collagen peptide response pattern to treatment with the non-steroidal anti-inflammatory drug sulindac [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P1-10-05.

Abstract P5-17-12: First-in-human expansion study of oral PMD-026 in metastatic triple negative breast cancer patients

Background: Durably effective therapeutic options remain elusive for metastatic triple negative breast cancer (mTNBC) patients. RSK is a novel target kinase for mTNBC, given its integral role in the MAPK/PDK-1 pathways. PMD-026, uniquely developed for TNBC, is a first-in-class, potent, oral RSK inhibitor that constitutes a promising avenue of treatment for mTNBC. PMD-026 demonstrated a favorable safety profile and initial signs of clinical benefit in metastatic breast cancer patients in Phase I. The current expansion is investigating PMD-026 in mTNBC patients whose disease has progressed on standard therapy. Methods: This open-label study evaluates the safety and efficacy of single agent PMD-026 in mTNBC patients. Target accrual for this study is a minimum of 20 mTNBC patients dosed at 200 mg q 12 hours who have measurable disease. A food effect (FE) sub-study is enrolling a total of 12 patients with a two-arm crossover design. Exploratory biomarker analysis of tumor tissue is being assessed for activated RSK2 levels. Exploratory objectives are to understand TNBC heterogeneity, with a view to identify patients who may benefit from PMD-026 optimally. Results: Based on the trial results thus far from 25 patients, PMD-026 continues to be well-tolerated with no G4 treatment-related adverse events. The noted toxicities include low incidence of elevated ALT/AST, rash, colitis or low-grade nausea. There has been no hair loss, myelosuppression or peripheral neuropathy. Given that TNBC is such a heterogeneous disease, we sought to identify subsets of patients with extensive prior therapy (≥ 5 lines) who may benefit from PMD-026 as a monotherapy. Based on ongoing analyses in the Phase I and Ib, patients diagnosed with TNBC at their initial diagnosis (de novo TNBC) stayed on study 3-4 times longer than patients who were initially treated for HR+ or HER2+ breast cancer but lost HR or HER2 expression to become TNBC (secondary TNBC). In addition, de novo TNBC patients treated at the recommended phase II dose (RP2D) of 200 mg BID with an H score for RSK2 ≥ 180 had a median progression free survival (PFS) of 3.3 months (n=3). In contrast, patients with an H score &lt; 180 had a median PFS of 0 months (n=3). Furthermore, the PFS of 3.3 months on PMD-026 is longer than the PFS of 1.7 months in a similar population of TNBC patients on chemotherapy, where the average number of prior treatments was 3a. . Conclusions: Updated safety, clinical activity, PK, and biomarker analyses will be presented. Clinical trial information: NCT04115306.aBardia et al, N Engl J Med 2021; 384:1529-154

Citation Format: Muralidhar Beeram, Judy S. Wang, Lida A. Mina, Pavani Chalasani, Rebecca A. Shatsky, Robert Wesolowski, Sara A. Hurvitz, Meghna S. Trivedi, Hyo S. Han, Amita Patnaik, My-my Huynh, Aarthi Jayanthan, Mary Rose Pambid, Lambert Yue, Gerrit Los, Sandra E. Dunn, Andrew Dorr. First-in-human expansion study of oral PMD-026 in metastatic triple negative breast cancer patients [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P5-17-12.

Abstract PD6-04: Mutational landscape and immune infiltration of breast cancer metastases to gynecologic and other organs

Introduction: Breast cancer metastases (BCM), which cause most breast cancer (BC)-associated mortality, have increased genetic complexity compared to early-stage disease. However, the contribution of genetic alterations to site of BCM is not well-understood. Different breast cancer subtypes have varying patterns of BCM, e.g., lobular carcinoma more frequently spreads to gynecologic (Gyn) organs and the GI tract, perhaps hinting at selection pressures wherein some organs are hospitable to tumors with certain genetic alterations. Methods: Relationships between BCM site and mutations detected by DNA next-generation sequencing (NGS; NextSeq 592 gene panels or NovaSeq whole exome sequencing) were investigated using 12,464 BC samples sequenced at Caris Life Sciences (sample sizes, Table 1). PD-L1 expression was tested through IHC (Clone SP-142 (cut-off ≥1, 1%)). Tumor mutational burden (TMB) was measured by totaling somatic mutations per tumor (high ≥ 10 mutations per MB). Immune cell fractions were calculated by deconvolution of whole-transcriptome data (NovaSeq) using Quantiseq (reference). Statistical significance was determined using chi-square and Wilcoxon rank sum tests adjusted for multiple comparisons. Results: Compared to primary breast tumors, BCM had increased frequency of TMB-H (10.08% vs. 4.94%), decreased PD-L1 positivity (21.09% vs. 35.82%), and were enriched for PIK3CA (34.62% vs 30.53%) and ESR1 mutations (13.34% vs 2.17%) (all P&lt;0.001). PD-L1 positivity was highest in BCM to lymph nodes (43.06%) and axilla (39.77%). BCM to Gyn organs had more lobular histology, the highest rate of hormone receptor (HR)+ tumors (77.17%), and rarely had high TMB (6.73%) or were PD-L1 positive (11.39%). Double dendrogram hierarchical clustering of BCM site by mutation frequency and pathway alterations revealed BCM to Gyn organs as a simplicifolious clade with a unique mutational pattern. Compared to BC in breast, BCM to Gyn organs had higher rates of mutations of PIK3CA, AKT1, and BRAF; more mutations in DNA repair (0.79% vs 0.06%), transcription factor (4.72% vs 0.93%), and Wnt signaling pathways (2.36% vs 1.47%); but no increase in BRCA mutations. BCM to brain had the most p53 pathway and homologous recombination (HR) pathway mutations (64.71% and 14.01%), while Gyn had the least (19.69% and 7.09%). Quantiseq RNA deconvolution revealed differences in tumor immune cell infiltrate by BCM site. Gyn metastases vs breast tumors had increased B cells (6.20% vs 5.40%), M2 macrophages (5.71% vs 4.07%), and NK cells (3.82% vs 3.18%) (all P&lt;0.01) and a M2/M1 macrophage ratio of 22.8:1 vs 1.3:1. Conclusions: BCM to Gyn organs have a unique mutational and immune suppression profile. Integrating the profiling with clinical outcomes may extend this prognostic signature and set the stage for improved treatment strategies for these patients. Confirmation from matched or sequential specimens could clarify tumor evolution. Our data support repeat biopsy of Gyn site metastases since more targetable mutations might be revealed. Targeting mechanisms of immunosuppression in Gyn BCM could expand therapeutic options.

Table 1.Breast Cancer TumorsTumor SiteTotalPredominant Breast Cancer SubtypeAll12464HR+/HER2- (51.6%)Breast5014HR+/HER2- (46.5%)Liver2003HR+/HER2- (63.3%)Bone1132HR+/HER2- (69.4%)Axilla1051HR+/HER2- (47.7%)Lung823HR+/HER2- (46.1%)Lymph Node647HR+/HER2- (43.4%)Chest/Chest Wall375HR+/HER2- (44.8%)Brain359TNBC (38.2%)Other315HR+/HER2- (57.1%)Skin282HR+/HER2- (50.7%)Connective Tissue193HR+/HER2- (51.8%)GI Organs143HR+/HER2- (69.9%)Gynecologic Organs127HR+/HER2- (76.4%)

Citation Format: Anna D Louie, Rani Chudasama, Sharon Wu, Marzia Capelletti, Daniel Magee, W. Michael Korn, Virginia Kaklamani, Antoinette R Tan, Pavani Chalasani, Wafik S El-Deiry, Don Dizon, Stephanie L. Graff. Mutational landscape and immune infiltration of breast cancer metastases to gynecologic and other organs [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr PD6-04.

Abstract GS3-10: Study of samuraciclib (CT7001), a first-in-class, oral, selective inhibitor of CDK7, in combination with fulvestrant in patients with advanced hormone receptor positive HER2 negative breast cancer (HR+BC)

Background: CDK7 inhibition is a promising therapeutic strategy in cancer; acting as a regulator of the cell cycle, transcription and endocrine receptor signalling [1]. Patients with HR+BC post CDK4/6 inhibitor treatment have a poor prognosis; median progression free survival (mPFS) of ~ 8 weeks for fulvestrant post CDK4/6i in HR+BC [2,3]. Pre-clinical HR+BC models indicate the potential for synergy when the CDK7 inhibitor samuraciclib is combined with the Selective Estrogen Receptor Degrader fulvestrant [4]Materials and Methods: This single arm cohort assessed the tolerability and efficacy of samuraciclib in combination with standard dose fulvestrant in patients with advanced HR+BC; all patients had previously received an aromatase inhibitor and a CDK4/6i for advanced disease.Results: 31 patients with HR+BC received the combination of standard dose with fulvestrant and samuraciclib. 6 patients received samuraciclib dose of 240mg once daily (QD) and 25 patients a dose of 360mg QD. The combination treatment was generally well tolerated, with adverse drug reactions (AE) of note being G1-2 nausea, vomiting and diarrhoea; the majority of patients staying on treatment until disease progression.RECIST evaluation indicates evidence of reduction in tumor disease burden, including a partial response in one patient who has been on treatment for ~ 1 year.Graphic illustrations of data, including ‘waterfall’ and ‘swimmer’ plots, will be presented along with stratification data based on demographic factors such as hepatic involvement and cfDNA analysis (ESR1m, PI3Km).Conclusions: Samuraciclib has demonstrated an acceptable safety profile with evidence of anti-tumour activity in combination with fulvestrant for patients with advanced HR+BC who have progressed on their prior CDK4/6i.References:1.Patel et al., Mol Cancer Therap. 20182.Juric et al., SABCS 20183.Lindeman et al., JCO 20214.Jeselsohn et al., SABCS 2019

Citation Format: Charles Coombes, Sasha J Howell, Matthew G Krebs, Simon Lord, Laura M Kenny, Ash Bahl, Glen Clack, Edward Ainscow, Paul A Dickinson, Raluca Fostea, Janine Mansi, Carlo Palmieri, Gianflippo Bertelli, Rinath Jeselsohn, Zahi Mitri, William J Gradishar, Sagar Sardesai, Joyce O'Shaughnessy, Patrick Ward, Pavani Chalasani, Manfred Lehnert, Simak Ali, Stuart McIntosh. Study of samuraciclib (CT7001), a first-in-class, oral, selective inhibitor of CDK7, in combination with fulvestrant in patients with advanced hormone receptor positive HER2 negative breast cancer (HR+BC) [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr GS3-10.

Sulindac Improves Stiffness and Quality of Life in Women Taking Aromatase Inhibitors for Breast Cancer

PURPOSE

To examine benefit of sulindac for relief of musculoskeletal symptoms (MSS) in patients stable on aromatase inhibitors (AIs).

METHODS

Sulindac was evaluated at 150 mg twice daily for effects on MSS at 3, 6, 9, and 12 months in 50 postmenopausal women stable on AI therapy for a median of 12.5 months for hormone receptor-positive breast cancer. A separate, non-randomized group of 50 similar patients was observed for change in MSS over 12 months. MSS severity was assessed using the Western Ontario and McMaster Universities Osteoarthritis (WOMAC) Index and Brief Pain Inventory Short Form (BPI-SF). The Functional Assessment of Cancer Therapy-General form (FACT-G) measured quality of life (QOL). Change in MSS and QOL across time was assessed in each group using linear mixed effects models.

RESULTS

Stiffness, not pain, was the main complaint at baseline. At 12 months, sulindac patients reported decreases (improvements) in mean (95% CI) Total WOMAC score [- 5.85 (- 9.73, - 1.96)] and WOMAC pain [- 5.40 (- 10.64, - 0 .18)], Stiffness [- 9.53 (- 14.98, - 4.08)] and Physical Function [- 5.61 (- 9.62, - 1.60)] subscales, but not BPI-SF worst pain. Among sulindac patients with higher baseline MSS severity, 35% experienced ≥ 50% improvement in Total WOMAC and Total FACT-G scores [6.18 (2.08, 10.27); P = 0.003]. For the observation group, MSS and QOL did not improve over 12 months, even among those with higher baseline MSS severity.

CONCLUSIONS

Sulindac may relieve MSS in AI patients, especially physical function and stiffness. Randomized controlled trials should further evaluate NSAIDs on AI-MSS and AI adherence.

TRIAL REGISTRATION NUMBER AND DATE OF REGISTRATION

NCT01761877, December, 2012.

A Phase II Study Evaluating the Safety and Efficacy of Sunitinib Malate in Combination With Weekly Paclitaxel Followed by Doxorubicin and Daily Oral Cyclophosphamide Plus G-CSF as Neoadjuvant Chemotherapy for Locally Advanced or Inflammatory Breast Cancer

INTRODUCTION

Neoadjuvant chemotherapy is standard treatment for locally advanced breast cancer (LABC) or inflammatory breast cancer (IBC). We hypothesized that adding sunitinib, a tyrosine kinase inhibitor with antitumor and antiangiogenic activity, to an anthracycline and taxane regimen would improve pathologic complete response (pCR) rates to a prespecified endpoint of 45% in patients with HER2-negative LABC or IBC.

METHODS

We conducted a multicenter, phase II trial of neoadjuvant sunitinib with paclitaxel (S+T) followed by doxorubicin and cyclophosphamide plus G-CSF for patients with HER2-negative LABC or IBC. Patients received sunitinib 25 mg PO daily with paclitaxel 80 mg/m² IV weekly ×12 followed by doxorubicin 24 mg/m² IV weekly + cyclophosphamide 60 mg/m² PO daily with G-CSF support. Response was evaluated using pCR in the breast and the CPS + EG score (clinical-pathologic scoring + estrogen receptor [ER] and grade).

RESULTS

Seventy patients enrolled, and 66 were evaluable for efficacy. Eighteen patients (27%) had pCR in the breast (10 had ER⁺ disease and 8 had triple-negative disease). When defining response as pCR and/or CPS + EG score ≤2, 31 (47%) were responders. In pateints with ER positive disease, 23 (64%) were responders. The most common toxicities were cytopenias and fatigue.

CONCLUSIONS

Neoadjuvant S+T followed by AC+G-CSF was safe and tolerable in LABC and IBC. The study did not meet the prespecified endpoint for pCR; however, 47% were responders using pCR and/or CPS + EG score ≤2. ER positive patients had the highest response rate (64%). The addition of sunitinib to neoadjuvant chemotherapy may provide promising incremental benefit for patients with ER positive LABC.

Immune responses to two and three doses of the BNT162b2 mRNA vaccine in adults with solid tumors

Vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have shown high efficacy, but immunocompromised participants were excluded from controlled clinical trials. In this study, we compared immune responses to the BNT162b2 mRNA Coronavirus Disease 2019 vaccine in patients with solid tumors (n = 53) who were on active cytotoxic anti-cancer therapy to a control cohort of participants without cancer (n = 50). Neutralizing antibodies were detected in 67% of patients with cancer after the first immunization, followed by a threefold increase in median titers after the second dose. Similar patterns were observed for spike protein-specific serum antibodies and T cells, but the magnitude of each of these responses was diminished relative to the control cohort. In most patients with cancer, we detected spike receptor-binding domain and other S1-specific memory B cell subsets as potential predictors of anamnestic responses to additional immunizations. We therefore initiated a phase 1 trial for 20 cancer cohort participants of a third vaccine dose of BNT162b2 ( NCT04936997 ); primary outcomes were immune responses, with a secondary outcome of safety. At 1 week after a third immunization, 16 participants demonstrated a median threefold increase in neutralizing antibody responses, but no improvement was observed in T cell responses. Adverse events were mild. These results suggest that a third dose of BNT162b2 is safe, improves humoral immunity against SARS-CoV-2 and could be immunologically beneficial for patients with cancer on active chemotherapy.

A randomized controlled trial of metformin in women with components of metabolic syndrome: intervention feasibility and effects on adiposity and breast density

PURPOSE

Obesity is a known risk factor for post-menopausal breast cancer and may increase risk for triple negative breast cancer in premenopausal women. Intervention strategies are clearly needed to reduce obesity-associated breast cancer risk.

METHODS

We conducted a Phase II double-blind, randomized, placebo-controlled trial of metformin in overweight/obese premenopausal women with components of metabolic syndrome to assess the potential of metformin for primary breast cancer prevention. Eligible participants were randomized to receive metformin (850 mg BID, n = 76) or placebo (n = 75) for 12 months. Outcomes included breast density, assessed by fat/water MRI with change in percent breast density as the primary endpoint, anthropometric measures, and intervention feasibility.

RESULTS

Seventy-six percent in the metformin arm and 83% in the placebo arm (p = 0.182) completed the 12-month intervention. Adherence to study agent was high with more than 80% of participants taking ≥ 80% assigned pills. The most common adverse events reported in the metformin arm were gastrointestinal in nature and subsided over time. Compared to placebo, metformin intervention led to a significant reduction in waist circumference (p < 0.001) and waist-to-hip ratio (p = 0.019). Compared to placebo, metformin did not change percent breast density and dense breast volume but led to a numerical but not significant decrease in non-dense breast volume (p = 0.070).

CONCLUSION

We conclude that metformin intervention resulted in favorable changes in anthropometric measures of adiposity and a borderline decrease in non-dense breast volume in women with metabolic dysregulation. More research is needed to understand the impact of metformin on breast cancer risk reduction.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02028221. Registered January 7, 2014, https://clinicaltrials.gov/ct2/show/NCT02028221.

Sulindac, a Nonselective NSAID, Reduces Breast Density in Postmenopausal Women with Breast Cancer Treated with Aromatase Inhibitors

PURPOSE

To evaluate the effect of sulindac, a nonselective anti-inflammatory drug (NSAID), for activity to reduce breast density (BD), a risk factor for breast cancer.

EXPERIMENTAL DESIGN

An open-label phase II study was conducted to test the effect of 12 months' daily sulindac at 150 mg twice daily on change in percent BD in postmenopausal hormone receptor-positive breast cancer patients on aromatase inhibitor (AI) therapy. Change in percent BD in the contralateral, unaffected breast was measured by noncontrast magnetic resonance imaging (MRI) and reported as change in MRI percent BD (MRPD). A nonrandomized patient population on AI therapy (observation group) with comparable baseline BD was also followed for 12 months. Changes in tissue collagen after 6 months of sulindac treatment were explored using second-harmonic generated microscopy in a subset of women in the sulindac group who agreed to repeat breast biopsy.

RESULTS

In 43 women who completed 1 year of sulindac (86% of those accrued), relative MRPD significantly decreased by 9.8% [95% confidence interval (CI), -14.6 to -4.7] at 12 months, an absolute decrease of -1.4% (95% CI, -2.5 to -0.3). A significant decrease in mean breast tissue collagen fiber straightness (P = 0.032), an investigational biomarker of tissue inflammation, was also observed. MRPD (relative or absolute) did not change in the AI-only observation group (N = 40).

CONCLUSIONS

This is the first study to indicate that the NSAID sulindac may reduce BD. Additional studies are needed to verify these findings and determine if prostaglandin E₂ inhibition by NSAIDs is important for BD or collagen modulation.

Immune Responses to COVID-19 mRNA Vaccines in Patients with Solid Tumors on Active, Immunosuppressive Cancer Therapy

Vaccines against SARS-CoV-2 have shown high efficacy, but immunocompromised participants were excluded from controlled clinical trials. We compared immune responses to the Pfizer/BioNTech mRNA vaccine in solid tumor patients (n=53) on active cytotoxic anti-cancer therapy to a control cohort (n=50) as an observational study. Using live SARS-CoV-2 assays, neutralizing antibodies were detected in 67% and 80% of cancer patients after the first and second immunizations, respectively, with a 3-fold increase in median titers after the booster. Similar trends were observed in serum antibodies against the receptor-binding domain (RBD) and S2 regions of Spike protein, and in IFNγ+ Spike-specific T cells. Yet the magnitude of each of these responses was diminished relative to the control cohort. We therefore quantified RBD- and Spike S1-specific memory B cell subsets as predictors of anamnestic responses to additional immunizations. After the second vaccination, Spike-specific plasma cell-biased memory B cells were observed in most cancer patients at levels similar to those of the control cohort after the first immunization. We initiated an interventional phase 1 trial of a third booster shot (NCT04936997); primary outcomes were immune responses with a secondary outcome of safety. After a third immunization, the 20 participants demonstrated an increase in antibody responses, with a median 3-fold increase in virus-neutralizing titers. Yet no improvement was observed in T cell responses at 1 week after the booster immunization. There were mild adverse events, primarily injection site myalgia, with no serious adverse events after a month of follow-up. These results suggest that a third vaccination improves humoral immunity against COVID-19 in cancer patients on active chemotherapy with no severe adverse events.

Abstract CT016: Clinical activity of single-agent ZN-c3, an oral WEE1 inhibitor, in a phase 1 dose-escalation trial in patients with advanced solid tumors

Introduction: ZN-c3 is a selective and orally bioavailable small molecule WEE1 inhibitor. WEE1 is a crucial component of the G2/M cell cycle checkpoint preventing cells from entering mitosis to allow repair of DNA damage before cell cycle progression. ZN-c3 has demonstrated significant growth inhibition in vitro in multiple cell lines from various cancer types and antitumor activity in vivo in human xenograft tumor models. Methods: ZN-c3-001 (NCT04158336) is a dose escalation, open-label, multicenter, Phase 1 clinical trial evaluating the safety, tolerability, and efficacy of ZN-c3 in subjects with advanced or metastatic solid tumors, refractory to standard therapy or for whom no standard therapy is available. ZN-c3 dosing was escalated from 25mg to 450mg administered orally QD. The primary objective of this study is to determine the schedule, Maximum Tolerated Dose (MTD), and Recommended Phase 2 Dose (RP2D) of ZN-c3. Subjects underwent imaging every 9 weeks to assess disease response. Here we report early signal of clinical activity of ZN-c3. Results: As of 30Nov2020 there were 39 subjects treated and of those, 30 experienced treatment related adverse events (TRAEs), the most frequently reported TRAEs were nausea, diarrhea, vomiting, and fatigue. Of the 16 subjects with post-baseline tumor assessments, 5 patients had stable disease (SD) and 2 subjects had partial responses (PR), as per RECIST 1.1. One was a 63-yo Caucasian male with Stage IV colorectal cancer with metastases to the liver, lymph nodes, and pleura who achieved a PR with 42% reduction in overall tumor burden. Carcinoembryonic Antigen tumor marker decreased from 327 ng/mL at baseline to less than 50 ng/mL after 3 weeks on treatment. The second subject was a 72-yo Caucasian female with Stage IV ovarian cancer with metastases to the pleura, peritoneum, and retroperitoneum who achieved a PR with a 56% reduction in overall tumor burden. CA-125 dropped from 610 kU/L at baseline to 125 kU/L within 4 weeks after first dose and normalized 3 weeks later. Based on MTD, as determined by the Bayesian Continual Reassessment model, the overall tolerability and toxicity, and the dose dependent pharmacokinetic profile, the recommended RP2D for ZN-c3 is determined to be 300mg, given orally as continuous once daily dosing. Conclusions: ZN-c3 shows early signal of clinical activity in heavily pretreated advanced solid tumor subjects. It appears safe and tolerable as a single agent at the identified RP2D. An expansion cohort will be included in this Phase 1 study to treat additional subjects. In addition, a Phase 2 clinical study is being planned to enroll additional subjects to further evaluate the efficacy of ZN-c3. Ongoing correlative studies will continue to determine specific mechanisms and biomarkers of response to ZN-c3.

Citation Format: Anthony Tolcher, Hirva Mamdani, Pavani Chalasani, Funda Meric-Bernstam, Mihaela Gazdoiu, Lukas Makris, Philippe Pultar, Dimitris Voliotis. Clinical activity of single-agent ZN-c3, an oral WEE1 inhibitor, in a phase 1 dose-escalation trial in patients with advanced solid tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr CT016.

First-in-human phase 1/1b expansion of PMD-026, an oral RSK inhibitor, in patients with metastatic triple-negative breast cancer

e13043

Background: P90 ribosomal S6 kinase (RSK) is an actionable molecular target against metastatic triple negative breast cancer (mTNBC). RSK is a major convergence point in the integral TNBC signaling pathways, MAPK and PDK-1. PMD-026 is a first-in-class oral RSK inhibitor with high selectivity. The dose escalation portion of this study established the RP2D of PMD-026 as 200 mg Q12. PMD-026 demonstrated good plasma exposure following oral dosing, with a T1/2 of ̃ 6 h (range 4-8 h), and achieved the targeted preclinical efficacious concentrations using a Q12h dosing schedule. PMD-026 also demonstrated a tolerable safety profile and initial signs of efficacy in patients with metastatic breast cancer. The intensity of RSK2 activation ranged from an H Score of 110-268 based on a CLIA companion immunohistochemistry assay. We present initial data from the expansion cohort. Methods: The primary aim of this single-arm, open-label, first-in-human phase 1/1b study is to evaluate the safety of single agent PMD-026 in patients with mTNBC. Secondary endpoints are clinical activity, pharmacokinetics, and correlative biomarker expression on tumor specimens. Patients are dosed at 200 mg twice daily in 21-day cycles. Eligible patients have measurable disease as per RECIST v1.1 and have had disease progression on or after standard of care treatment. Tumor tissue is assessed to retrospectively correlate RSK2 activity by immunohistochemistry (IHC) with clinical outcomes. Pharmacokinetics are assessed along with a food effect (sub-study with n=12). In addition, a pharmacodynamic marker, YB-1 phosphorylation, is being explored in peripheral blood mononuclear cells before and during treatment. Results: As of February 16, 2021, 7 patients with mTNBC (median age 62 years, range 33-74) have been enrolled in the phase 1b Expansion (median of 7 prior lines of therapy). Notable prior therapies in the phase 1b include sacituzumab govitecan (n=4) and atezolizumab/nab-paclitaxel (n=1). Patients in escalation and expansion treated with the RP2D had median progression free survival of 30 vs 99 days for low vs high RSK2 expression, respectively. This cut-off will be further evaluated in the expansion phase of the study. Conclusions: Updated safety, clinical activity, pharmacokinetic, and biomarker analyses will be presented. Target accrual for phase 1b Expansion is a minimum of 20 patients with mTNBC. Clinical trial information: NCT04115306.

Confirmed long-term safety and efficacy of prophylactic treatment with BAY 94-9027 in severe haemophilia A: final results of the PROTECT VIII extension study

Introduction

The phase 2/3 PROTECT VIII main study demonstrated efficacy and safety of BAY 94–9027 (damoctocog alfa pegol; Jivi^®), a B‐domain‐deleted recombinant factor VIII (FVIII), site‐specifically PEGylated to extend its half‐life.

Aim

To report the final efficacy and safety data for BAY 94–9027 from the PROTECT VIII extension.

Methods

Previously treated males aged 12–65 years with severe haemophilia A (FVIII <1%) who completed the multicentre, open‐label PROTECT VIII main study were eligible for the extension. Patients received either on demand or prophylaxis treatments (30‒40 IU/kg twice weekly [2 × W], 45‒60 IU/kg every 5 days [E5D], or 60 IU/kg every 7 days [E7D]) and could switch to any prophylaxis regimen (variable frequency) as needed. Annualised bleeding rates (ABR), zero bleeds and safety outcomes were included in this final analysis.

Results

At extension completion, patients (n = 121) received BAY 94–9027 for a median (range) total time of 3.9 (0.8–7.0) years. Median (Q1; Q3) total ABR was 1.49 (0.36; 4.80) for prophylaxis patients (n = 107), compared with 34.09 (20.3; 36.6) for on‐demand patients (n = 14). Median total ABRs for 2 × W (n = 23), E5D (n = 33), E7D (n = 23) and variable frequency (n = 28) groups were 1.57, 1.17, 0.65 and 3.10, respectively. Of prophylaxis patients, 20.6% were bleed‐free during the entire extension (median time, 3.2 years) and 50.0% were bleed‐free during the last 6 months. No patient developed FVIII inhibitors. No deaths or thrombotic events were reported.

Conclusions

Efficacy and safety of BAY 94–9027 was confirmed, with extension data supporting its use as a long‐term treatment option for patients with haemophilia A.

Shear wave elastography detects novel imaging biomarkers of aromatase inhibitor-induced joint pain: a pilot study

Aim

To determine whether differences in joint and tendon stiffness as measured by ultrasound shear wave elastography are present in breast cancer patients with aromatase inhibitor-associated arthralgias compared to age-comparable healthy control women.

Methods

Postmenopausal women with stage I–III breast cancer who were taking adjuvant aromatase inhibitors and complained of joint pain were enrolled (n = 6). Postmenopausal women with no history of breast cancer, hormone treatment, or joint pain served as controls (n = 7). All subjects had bilateral hands and wrists evaluated by gray-scale and power Doppler ultrasound, and shear wave elastography ultrasound.

Results

Patients with AI-associated arthralgias had significantly stiffer tendons than controls in the 1^st extensor compartment (long axis; p = 0.001), 4^th extensor compartment (long axis; p = 0.014), 3^rd metacarpophalangeal joint (p = 0.002), the pooled values of the extensor compartments, both long (p = 0.044) and short axes (p = 0.035), and the pooled values for the metacarpophalangeal joints (p = 0.002). On ultrasound, the patients (but not controls) presented with hyperemia and increased tenosynovial fluid in the flexor and extensor tendon sheaths, and the median nerves were symptomatic and bifid; however, these differences were not statistically significant.

Conclusions

This is the first study to identify increased tendon stiffness as a putative physiological characteristic of aromatase inhibitor–associated arthralgias. Future studies should determine whether increased tendon stiffness is a risk factor for the development of aromatase inhibitor–associated arthralgias, or a result of aromatase inhibitor treatment.

Abstract PS12-20: A dose escalation study of the novel oral SERD-ZN-c5 in women with ER-positive, HER2-negative advanced/metastatic breast cancer

Background: ZN-c5 is an orally bioavailable selective estrogen receptor degrader (SERD) that binds potently to the estrogen receptors alpha and beta. It shows improved activity over fulvestrant in human tumor xenograft models and activity in tumor models that are resistant to tamoxifen. This is a Phase 1/2, open-label, multicenter, dose-escalation and expansion study to evaluate the safety, tolerability, pharmacokinetics (PK), and clinical activity of ZN-c5 in subjects with advanced/metastatic estrogen receptor (ER) positive/ human epidermal growth factor receptor (HER2) negative breast cancer, both as monotherapy and in combination with palbociclib. The results from the ongoing monotherapy dose escalation are reported. Methods: Single agent ZN-c5 is being evaluated at sequentially escalating doses starting at 50 mg/day, administered orally, once daily (QD). The endpoints are to determine a maximum tolerated dose (MTD) or recommended Phase 2 dose (RP2D), preliminary clinical activity and to characterize the PK profile. Subjects must be intolerant to or have breast cancer refractory to established therapies and to have received up to 2 prior lines of chemotherapy for the treatment of advanced breast cancer. Subjects must have a documented prior response to endocrine therapy for advanced/metastatic disease (SD, PR, or CR) lasting &gt; 6 months or disease recurrence after at least 24 months of adjuvant endocrine treatment. Results: A total of 15 female subjects (median age 57 years, range 51 - 89 years) were enrolled across 5 cohorts (3 subjects/dose level). The dose levels were 50, 75, 100, 150, and 300 mg/day. The subjects had a median of 4 prior therapies for advanced/metastatic disease, with a median of 3 prior hormonal-based therapies and a median of 1 prior chemotherapy. Eleven of 15 subjects (73%) received prior fulvestrant. The cut off-date for this analysis was 30 June 2020. There was no increase in incidence or severity of TEAEs with increase in dose level. The most frequent TEAEs reported in &gt; 1 subject were nausea (33%), arthralgia, cough, musculoskeletal pain and vomiting (20% each), alanine aminotransferase increased, anemia, back pain, blood alkaline phosphatase increased, breast pain, diarrhea, fatigue, gamma-glutamyl transferase increased, headache, hypophosphatemia, myalgia and skin mass (13% each). Grade 3 events were COVID-19, hypercalcemia, arthralgia, back pain musculoskeletal chest pain, pain in extremity and hypertension, none were deemed related to ZN-c5. Grade 4 events were not reported. No bradycardia was observed. A single subject reported a Grade 1 visual field defect, not deemed related to ZN-c5. No DLTs were reported. ZN-c5 demonstrated a best response of stable disease (SD) in 10/15 subjects (66.5%), while progression of disease (PD) was reported in 5/15 subjects (33.5%). The clinical benefit rate (CBR, SD ≥ 24 weeks) was 40%. In addition, the progression free survival (PFS) was a median of 3.8 months (95% [CI], 1.6 to 6.3). The preliminary PK was characterized by fast absorption with median Tmax values of 1 - 2 hrs. The exposures were approximately dose-proportional at the dose levels of 50 - 100 mg and less than dose-proportional between 100 - 300 mg. No ZN-c5 accumulation after 15 days of QD dosing was observed. The estimated mean elimination half-lives ranged between 11 - 18 hrs. Conclusion: This monotherapy dose escalation study demonstrates that ZN-c5 is very well-tolerated and has promising clinical activity in patients with ER+/HER2-negative advanced breast cancer who have disease that progressed on standard therapies. The trial with ZN-c5 in monotherapy and with palbociclib is ongoing and the RP2D has not been determined yet.

Citation Format: Pavani Chalasani, Vandana Abramson, Joanne Mortimer, Julie R Nangia, Jose Suarez, Matt Suster, Mieke Ptaszynski, Kevin Kalinsky. A dose escalation study of the novel oral SERD-ZN-c5 in women with ER-positive, HER2-negative advanced/metastatic breast cancer [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS12-20.

Abstract PS11-33: A first-in-human Phase 1/1b multicenter, open-label dose escalation study to assess safety and tolerability of PMD-026, a first-in-class oral RSK inhibitor, in metastatic breast cancer patients

Background: Metastatic breast cancer (mBC) remains an aggressive disease with limited durable treatment options; the worst prognosis among the breast cancer subtypes is typically seen in metastatic triple-negative breast cancer (mTNBC). Given that unmet need, we sought to identify an actionable molecular target to combat mTNBC. Promising preclinical activity identified p90 ribosomal s6 kinase 2 (RSK2) as a key kinase in mTNBC. PMD-026 is a potent, oral, small molecular RSK inhibitor with high selectivity for the RSK2 isoform. RSK is a major convergence point in the important MAPK and PDK-1 signaling pathways, which drive TNBC cell survival, proliferation, and drug resistance.

Methods: The primary aim of this single-arm, open-label, first-in-human, phase 1/1b study (NCT04115306) is to evaluate the safety of single agent PMD-026 in patients with mBC. Secondary endpoints are clinical activity, pharmacokinetics (PK) and correlative biomarker expression on tumor specimens. Patients are dosed orally once or twice daily in 21-day cycles with measures to adapt the dosing schedule based on the PK data, as needed. In dose escalation, patients must have mBC with evaluable or measurable disease by RECIST v1.1. In dose expansion, patients must have mTNBC with measurable disease by RECIST v1.1. Patients must have progressed on or after standard of care therapy. Tumor tissue is required to retrospectively correlate RSK2 activity with clinical outcomes via immunohistochemistry using a CAP/CLIA certified companion diagnostic (CDx).

Results: Twelve mBC patients (ER+ mBC n=5, mTNBC n=7) who have failed standard chemotherapy as well as targeted therapies such as CDK4/6 inhibitors and immunotherapies have been enrolled to date. Patients have been treated in escalating cohorts of 25, 50, 100, 200, 400 (200 q12) or 600 mg (300 q12) of PMD-026 administered orally daily. At 400 mg the dose schedule was changed from daily to q12 hrs based on PK results to optimize drug exposure over a 24-hr timeframe in patients. The PK of PMD-026 showed linear exposure and a high volume of distribution. The AUC was ~9100 hr*ng/ml on Day 1 when PMD-026 was dosed at 200 mg qd demonstrating high exposure. In addition, when dosed at 200 mg q12 hrs, PMD-026 serum levels approached the preclinically established desired level of 1 µM over 24 hrs. In the 200 mg q12 hrs cohort, adverse events consisted of G2 GERD (n=1) and G2 neutropenia (n=1). Initial signs of activity were observed as CT-identified necrosis in a neck node metastasis (n=1) and transient decrease in CA 27-29 (n=1). While the 200 mg q12 hrs dose was generally well-tolerated, there were 2 dose limiting toxicities at 300 mg q12 hrs including syncope (n = 1) and vomiting with dehydration leading to reversible acute kidney injury (n = 1). To further understand the patient population, RSK2 activation was assessed in tumor samples from all patients. RSK2 was activated in all of the tumors and the H-Score ranged from 110 to 198 using the CDx platform.

Conclusions: Preliminary evidence indicates that PMD-026 is well-tolerated at dose levels up to 200 mg q12 with initial signs of activity; pharmacokinetics showed good linear exposure. Updated safety, clinical activity, pharmacokinetic and biomarker analyses will be presented; target accrual for Phase 1b Expansion is approximately 20 mTNBC patients. (clinicaltrials.gov NCT04115306).

Citation Format: Murali Beeram, Judy S. Wang, Pavani Chalasani, Lida Mina, Amita Patnaik, Mary Rose Pambid, Aarthi Jayanthan, My-my Huynh, Gerrit Los, Sandra E. Dunn, F. Andrew Dorr. A first-in-human Phase 1/1b multicenter, open-label dose escalation study to assess safety and tolerability of PMD-026, a first-in-class oral RSK inhibitor, in metastatic breast cancer patients [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS11-33.

Abstract PS10-03: Interim safety and efficacy analysis of phase IB / II clinical trial of tucatinib, palbociclib and letrozole in patients with hormone receptor and HER2-positive metastatic breast cancer

Background: In hormone receptor-positive / HER2-positive (HR+/HER2+) breast cancer, the HER2 and estrogen receptor (ER) signals merge on the cyclin D1-CDK4/6-RB1 pathway. Thus, a combined pharmacological intervention with individual drugs targeting HER2, ER and CDK4/6 is warranted. Here, we present the safety and efficacy results of the combination of tucatinib with letrozole and palbociclib in patients (pts) with HR+/HER2+ metastatic breast cancer (MBC) (NCT03054363).

Methods: Pts with HR+/HER2+ MBC previously treated with at least 2 HER2-targeted agents were enrolled in this phase IB/II clinical trial. Pts with untreated asymptomatic or stable treated brain metastasis (BM) were included. Pts with treated progressing BM were enrolled after local treatment and classified as treated stable. Treatment consisted of tucatinib 300mg PO BID and letrozole 2.5mg PO daily continuously, and palbociclib 125mg PO daily 21 days on, 7 days off. Due to drug-drug interaction issues found in the middle of the trial and not related to this study, the dose of sensitive CYP3A4 substrate palbociclib was reduced to 75mg for all study participants, as it became evident that tucatinib is a strong CYP3A4 inhibitor. The primary end-points were assessment of safety using CTCAE v.4.03 criteria, and progression free survival (PFS). Secondary end-points included pharmacokinetic evaluation (PKs) and objective response rate by RECIST 1.1. BM response was evaluated using RANO-BM criteria. All pts who received at least one cycle of therapy were assessed for safety.

Results: Between 11.21.2017 and 04.20.2020, we enrolled 42 pts of whom 40 were evaluable. Median age was 52.5 years (range, 22 to 82) and the median number of prior lines of therapy for MBC was 2 (range, 0 to 7); 23 pts (58%) had visceral disease and 15 (38%) had BM. All pts had prior therapy with trastuzumab and pertuzumab and 18 pt (45%) had prior T-DM1. As of 06.15.2020 data cut off, 14 patients were on active therapy while 26 were off study (22 due to progressive disease [PD], 1 due to toxicity and 3 for other reasons). Median follow up time was 6 months. The combination was well tolerated with manageable and expected adverse events (AEs). The most common grade ≥3 AEs were neutropenia (25 pts, 60%), leukopenia (10 pts, 24%), diarrhea (8 pts, 19%), fatigue (6 pts, 14%), and infections (6 pts, 14%). One pt came off study due to asymptomatic grade 4 elevated LFTs that resolved without sequelae. There were no deaths due to AEs. Among 26 pts with measurable disease at the time of data cut-off, 8 pts (31%) had partial response, 16 pts (62%) had stable disease (SD) (7 pts [27%] had SD for ≥ 6 months and 6 pts [23%] have not yet reached 6 months of follow up) and 2 pts (8%) had PD. Among 14 patients with BM and evaluable disease by RANO-BM, 1 pt had complete response in the brain, 6 pts had SD in the brain for ≥6 months, and 7 pts had SD for 2-6 months (4 pts on active therapy have not yet reached 6 months of follow up). Median PFS is 8.7 months (10.1 months for pts without BM and 6.0 months for those with BM). Updated analysis including PKs, tumor response, and PFS will be presented.

Conclusion: The combination of tucatinib with letrozole and palbociclib showed a tolerable and manageable safety profile and evidence of considerable anti-tumor activity that warrant further clinical investigation in pts with HR+/HER2+ MBC.

Citation Format: Elena Shagisultanova, William Gradishar, Ursa Brown-Glaberman, Pavani Chalasani, Andrew J. Brenner, Alison Stopeck, Jose Mayordomo, Jennifer R. Diamond, Peter Kabos, Virginia F. Borges. Interim safety and efficacy analysis of phase IB / II clinical trial of tucatinib, palbociclib and letrozole in patients with hormone receptor and HER2-positive metastatic breast cancer [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS10-03.

Diffuse tensor imaging of lower extremities: a novel MR imaging technique for chemotherapy-induced peripheral neuropathy

PURPOSE

Chemotherapy-induced peripheral neuropathy (CIPN) is caused by drug-induced damage to the axons which is not detected easily due to lack of reliable, clinically applicable modalities. Diffuse tensor imaging (DTI) allows for quantitative measurements of fractional anisotropy (FA) and apparent diffusion coefficient (ADC), which have been shown to detect nerve injury by Magnetic Resonance Imaging (MRI).

METHODS

We sought to evaluate if DTI could be used for detection of CIPN in patients with breast cancer treated with a taxane. Patients with h/o exposure to neurotoxic chemotherapy, diabetes, or peripheral neuropathy were excluded. Patients completed pre- and post-chemotherapy MRI of bilateral legs and FACT&GOG-Ntx. Genotyping of single-nucleotide variations (SNVs) was performed to detect known associations with CIPN.

RESULTS

We had 14 evaluable patients in this prospective trial. Mean FA values post-chemotherapy were significantly lower than baseline at mid-calf (p < 0.0001) and ankle (p = 0.03). We did not find any significant change in mean ADC values. In patients without symptomatic neuropathy, mean FA values decreased more than symptomatic patients at mid-calf (p < 0.001). Of the 41 genotyped SNVs, only rs8110536 was found to be significantly associated with development of CIPN.

CONCLUSIONS

Our results show that FA values are indicative of CIPN and differential changes in FA values in symptomatic versus asymptomatic patients highlights its potential to be further studied as a predictive biomarker for CIPN. This is the first study to highlight a non-invasive, imaging based, objective biomarker which, if validated, can be translated into clinic easily.

Rare Tumor-Normal Matched Whole Exome Sequencing Identifies Novel Genomic Pathogenic Germline and Somatic Aberrations

Whole exome sequencing (WES) of matched tumor-normal pairs in rare tumors has the potential to identify genome-wide mutations and copy number alterations (CNAs). We evaluated 27 rare cancer patients with tumor-normal matching by WES and tumor-only next generation sequencing (NGS) as a comparator. Our goal was to: 1) identify known and novel variants and CNAs in rare cancers with comparison to common cancers; 2) examine differences between germline and somatic variants and how that functionally impacts rare tumors; 3) detect and characterize alleles in biologically relevant genes-pathways that may be of clinical importance but not represented in classical cancer genes. We identified 3343 germline single nucleotide variants (SNVs) and small indel variants-1670 in oncogenes and 1673 in tumor suppressor genes-generating an average of 124 germline variants/case. The number of somatic SNVs and small indels detected in all cases was 523:306 in oncogenes and 217 in tumor suppressor genes. Of the germline variants, six were identified to be pathogenic or likely pathogenic. In the 27 analyzed rare cancer cases, CNAs are variable depending on tumor type, germline pathogenic variants are more common. Cell fate pathway mutations (e.g., Hippo, Notch, Wnt) dominate pathogenesis and double hit (mutation + CNV) represent ~18% cases.

Abstract C124: Breast density and metabolic risk factors: Cross-sectional analysis of the baseline data from a phase II breast cancer prevention trial

Breast density is an established breast cancer risk factor. Metabolic disturbances and high adiposity also increase breast cancer burden, but their relationships with breast density are not clearly defined, possibly due to the limitation of mammography density measurements in obese women. We are presently conducting a phase II double-blind, randomized, placebo-controlled clinical trial to study the effect of metformin on obesity-associated breast cancer risk in overweight and obese premenopausal women with metabolic disturbances. One hundred and fifty-one participants with a large waist (≥88 cm or ≥80 cm for Asian Americans and individuals with PCOS) and one other component of metabolic syndrome (elevated triglyceride, reduced HDL-C, elevated blood pressure, or elevated fasting glucose) were accrued and randomized (1:1) to receive metformin 850 mg BID or placebo for 12 months. The primary study endpoint is change in breast density. Secondary endpoints are changes in serum insulin, insulin-like growth factor axis, adipokines, waist circumference and body weight. Thirty-six percent of the accrued participants are Hispanics. The average body mass index, waist circumference and waist-to-hip ratio of the accrued participants are 37.8 ± 6.8 kg/m2, 110.8 ± 12.4 cm and 0.90 ± 0.07, respectively. We expect to complete our clinical trial in December 2018. We performed cross-sectional analyses of the baseline data to determine the associations between metabolic disturbances and breast density parameters acquired by fat-water MRI on noncompressed breasts. This is especially relevant in our study cohort because the compressed breast thickness is greater in obese women, which results in decreased image contrast on mammogram. Potential differences by ethnicity were explored. We showed that percent density and absolute density were not related to anthropometric measurements of adiposity for the overall cohort, with similar results by ethnicity. Having elevated fasting glucose in women with a large waist was related to a lower percent density and absolute density for the overall cohort, and the association was only observed in Hispanics. Our work is the first to compare breast density assessed by fat-water MRI by ethnicity. Further research is required to confirm our findings. Due to the rising rates of obesity in the United States, we strongly believe that this trial will have an important impact in public health, especially in minority population.

Citation Format: Jesse Trujillo, Edgar Tapia, Diana Villa-Guillen, Pavani Chalasani, Cynthia Thomson, Maria Altbach, Jean-Phillipe Galons, Jessica Martinez, Denise Roe, Amit Algotar, H.H. Sherry Chow. Breast density and metabolic risk factors: Cross-sectional analysis of the baseline data from a phase II breast cancer prevention trial [abstract]. In: Proceedings of the Eleventh AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2018 Nov 2-5; New Orleans, LA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(6 Suppl):Abstract nr C124.

Changes in serum estradiol levels with Estring in postmenopausal women with breast cancer treated with aromatase inhibitors

BACKGROUND

Anti-estrogen therapy is an effective intervention for preventing reoccurrence of hormone receptor-positive breast cancer in women. However, the side effects of anti-estrogen therapy, including urogenital symptoms, have been reported to cause significant morbidity. There is controversial data, mainly due to small sample sizes, reporting on the safety and efficacy of using vaginal estrogen to treat urogenital symptoms in patients on aromatase inhibitor therapy.

METHODS

We proposed a prospective trial to measure the change in blood estradiol levels in postmenopausal women with hormone receptor-positive breast cancer undergoing treatment with aromatase inhibitors when treated with vaginal estrogen preparation, Estring, for their urogenital symptoms. Only 8 prospective patients were enrolled, and the study was amended to include 6 retrospective patients who were treated similarly. Blood estradiol levels were measured at baseline and at week 16 for all patients.

RESULTS

The median age for all patients was 55 years, and the majority of them were treated with anastrozole. There was no significant difference between baseline and week 16 estradiol levels (p = 0.81). In addition, patients in the prospective group reported subjective improvement in their vaginal dryness symptoms questionnaires.

CONCLUSIONS

The vaginal estrogen preparation, Estring, did not cause persistent elevations in serum estradiol levels and might be a safer option for women with significant urogenital symptoms requiring estrogen therapy.

IMPLICATIONS FOR CANCER SURVIVORS

Vaginal estrogen preparation, Estring, might be an option for women with hormone receptor positive breast cancer who have persistent urogenital symptoms.

Longitudinal Dyadic Interdependence in Psychological Distress Among Latinas With Breast Cancer and Their Informal Caregivers

Cancer diagnosis and treatment can generate substantial distress for both survivors and their informal caregivers, defined as family members or friends who provide care and assistance to the cancer survivor. The primary aim of this investigation is to test a model of dyadic interdependence in distress experienced by Latina breast cancer survivors and their informal caregivers to determine if each influences the other. Methods: To test this prediction, 209 Latinas with breast cancer and their informal caregivers (dyads) were followed for 4 waves of assessment over the course of 6 months. Both psychological (depression, anxiety, perceived stress) and physical (number of symptoms, symptom distress) indicators of distress were assessed. Longitudinal analyses of dyadic data were performed in accordance with the actor-partner interdependence model using linear mixed effects modeling. Results: Findings indicated that psychological distress was interdependent between cancer survivors and their informal caregivers over the 6 months of observation. Caregivers experienced greater depression, anxiety, and stress to the extent that the survivors reported such distress, and vice versa. These effects held, even when controlling for nature of the survivor-caregiver relationship (married to each other or not), education, and the dyads' baseline similarity on distress. However, there was no such evidence of interdependence on indicators of physical distress. Conclusions: These findings are consistent with emotional contagion processes by which psychological distress is transmitted over time between cancer survivors and their informal caregivers. Latina cancer survivors are a particularly vulnerable population due to health disparities, linguistic barriers, and socioeconomic challenges. Management of psychological distress is of particular concern in this population. These findings point to the potential importance of caregiver well-being for the welfare of Latina breast cancer survivors.

Oxylipins Correlate with Quality of Life in Women Taking Aromatase Inhibitors for Breast Cancer

The purpose of this study was to determine if oxylipins – oxygenated bioactive lipid metabolites of ω-3 and ω-6 fatty acids with varying roles in inflammation and pain – correlate with aromatase inhibitor-associated arthralgia (AIA) and quality of life (QOL) in early stage breast cancer (ESBC) patients. Methods: ESBC patients on AI therapy were enrolled to an open-label study of sulindac, a non-steroidal anti-inflammatory drug (NSAID), for 12 months (n = 47). Pre-intervention arthralgia and physical function were assessed using the Western Ontario and McMaster Universities Osteoarthritis (WOMAC) questionnaire, where higher scores indicate worse symptoms. The Functional Assessment of Cancer Therapy – General (FACT-G) questionnaire was used to assess QOL, where higher scores indicate better QOL. A total of 53 plasma oxylipins in plasma were quantified by mass spectrometry. Pearson's correlation was used to measure the association between pre-intervention oxylipin concentrations, arthralgias and QOL. Results: Prior to initiating sulindac, baseline levels of 17 oxylipins were found to be significantly correlated with QOL scales. This included inverse associations between QOL and seven pro-inflammatory products of ω-6 fatty acid metabolism. Notably, prostaglandin E2, the primary target of NSAIDs, was negatively correlated with Social Well-Being (rho = −0.30; P = 0.04). Conversely, resolvin D1, a potent anti-inflammatory lipid, was positively associated with Total FACT-G (rho = 0.31; P = 0.03) and Emotional Well-Being (rho = 0.37; P = 0.01). Two ω-3 metabolites with unknown mechanisms were correlated with both QOL and WOMAC; 19,20-DiHDPE was positively correlated with Total (rho = 0.34; P = 0.02) and Social FACT-G (rho = 0.32; P = 0.03), and inversely with Total WOMAC (rho = -0.303; P = 0.04) and Stiffness (rho = −0.32; P = 0.03); and 5(6)-DiHETE was inversely correlated with Social FACT-G (rho = −0.33; P = 0.02) and positively with Total WOMAC (rho = 0.31; P = 0.04). Conclusions: This is the first evidence that plasma oxylipin metabolites of ω-3/ω-6 fatty acids correlate with QOL and arthralgia symptoms in patients on AIs and suggests oxylipins as a potential novel target for improving QOL and adherence to AI therapy in patients with ESBC.

Aromatase Inhibitors and Risk of Arthritis and Carpal Tunnel Syndrome among Taiwanese Women with Breast Cancer: A Nationwide Claims Data Analysis

Tamoxifen or aromatase inhibitor (AI) therapy may prevent breast cancer recurrence, however, adverse effects may lead to treatment discontinuation. Evidence regarding the occurrence of AI-associated musculoskeletal problems among Asians is scarce. We identified women with breast cancer-initiating tamoxifen or AIs from the Taiwan National Health Insurance Research Database (2007-2012). Using multivariable cause-specific hazard models, we examined the association between endocrine therapy and the risk of any arthritis and carpal tunnel syndrome, adjusting for age, prior cancer treatment, and other health status factors. Among 32,055 eligible women with breast cancer (mean age = 52.6 ± 11.5 years), 87.4% initiated tamoxifen, 3.9% initiated anastrozole, 8.0% initiated letrozole, and 0.7% initiated exemestane. AI users had a higher 1-year cumulative incidence for any arthritis (13.0% vs. 8.2%, p < 0.0001) and carpal tunnel syndrome (1.4% vs. 0.8%, p = 0.008). Compared to tamoxifen users, AI users had a higher risk of any arthritis [adjusted hazard ratio (aHR) = 1.21, 95%CI = 1.09-1.34] and carpal tunnel syndrome (aHR = 1.68, 95%CI = 1.22-2.32). No significant difference was observed in the risks of any arthritis and carpal tunnel syndrome across different AIs. Taxane use was not associated with any arthritis (aHR = 0.92, 95%CI = 0.81-1.05) or carpal tunnel syndrome (aHR = 0.97, 95%CI = 0.67-1.40) compared to other chemotherapies. Taiwanese women with breast cancer-initiating AIs had an increased risk of arthritis and carpal tunnel syndrome compared to those who initiated tamoxifen.

Abstract P5-13-05: Gene expression changes with neoadjuvant hormonal treatment

Breast cancers (BC) expressing estrogen and/or progesterone receptors, referred to as hormone receptor (HR)-positive represent the largest molecular subset of breast tumors. Fortunately, estrogen receptor expression on the cell surface serves as a drug target for endocrine therapy. In HR+, human epidermal growth factor receptor-2 (HER2) negative BC, neoadjuvant endocrine therapy (NET) is being increasingly used. While NET has been shown to reduce tumor cell proliferation causing apoptosis, up to 20% of tumors do not respond. Currently there are no validated predictive gene signatures distinguishing responders from non-responders to NET. Furthermore, there are limited data on the effects of different NET regimens in vivo and how they vary between responders and non-responders.

Methods: We conducted a retrospective translational study in patients who were treated with NET at our institution. This study was approved by our institutional review board. Paired pre-treatment and surgical samples were collected from 24 patients along with clinico-pathological information. Responders were defined as those with a preoperative endocrine prognostic index (PEPI) score of 0. RNA isolation was performed using the Roche HighPure FFPET RNA Isolation spin-column kit. Purified RNA was hybridized with the PanCancer Code Set and finally the cartridge was scanned on the nCounter Digital Analyzer. Raw counts from each gene were imported into the nSolver Analysis. Log2 normalized data obtained from Nanostring nCounter analysis was analyzed for differentially expressed genes between pre- and post-treatment samples. The bioinformatics analysis was carried out using nCounter analysis software.

Results: The median age at diagnosis was 64 years and NET used was anastrozole alone or in combination with fulvestrant. At baseline the majority of tumors were invasive ductal carcinomas (n=18), grade II (n=18), with a Ki67% &gt;15% (n=16). Median duration of treatment with NET was 5 months (range 2-10 months). Nine tumors were defined as responders to NET and 15 were non-responders. In all of the 24 paired samples, we found 123 genes with a statistically significant change in expression (defined by greater than two-fold change and a false discovery rate adjusted p-value &lt;0.05) in the surgical specimen compared to pre-treatment biopsy. Genes in the Janus kinase-signal transducers and activators of transcription (Jak-STAT) signaling pathway, mitogen-activated protein kinase (MAPK) signaling pathway, RAS signaling, cytosine-cytosine receptor interaction and the Phosphatidylinositol-3-kinase/Akt/mammalian target of rapamycin (PI3K-Akt) signaling pathway were found to be upregulated whereas genes in cell cycle pathway were downregulated in the surgical specimens after NET. Comparing pre-treatment samples of responders to non-responders 25 genes involving PI3K-Akt, Notch signaling and Fanconi anemia pathway were differentially expressed.

Conclusions: In our retrospective translational study we found that NET upregulates genes in the Jak-STAT, MAPK, RAS, cytosine-cytosine receptor interaction and PI3K-Akt signaling pathways and downregulates cell cycle pathway genes independent of type or duration of NET. We also found multiple genes involving the PI3K-Akt and Notch pathway were differentially expressed in pre-treatment specimens among responders compared to non-responders. While the sample size comparing responders versus non-responders was inadequate, our results suggest some early trends which warrant further investigation.

Citation Format: Darien E Reed, Ritu Pandey, Jennifer M Segar, Michele Chu, Lauren LeBeau, Pavani Chalasani. Gene expression changes with neoadjuvant hormonal treatment [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P5-13-05.

Abstract P3-08-27: Imaging predictors for development of chemotherapy induced peripheral neuropathy

Background: Chemotherapy induced peripheral neuropathy (CIPN) can affect up to a third of patients undergoing chemotherapy. CIPN is thought to be caused by drug induced damage to the peripheral motor or sensory nervous system. Symptoms range from tingling and numbness to balance issues and falls. Based on severity of symptoms, chemotherapy (CTX) is delayed, reduced, or discontinued which can adversely affect outcomes. Currently there are no predictive biomarkers to identify those at risk of developing CIPN. Diffuse tensor imaging (DTI), a subtype of diffusion-weighted imaging (DWI), measured by routine magnetic resonance imaging (MRI) is being increasingly evaluated to assess nerve fiber trajectory. DTI allows for quantitative measurements such as fractional anisotropy (FA) and apparent diffusion coefficient (ADC) which have shown some promising but mixed results in evaluating peripheral neuropathy and CIPN in some studies. We conducted a pilot study to evaluate if quantitative DTI measurements, FA and ADC, at mid-calf and ankle can evaluate CTX induced nerve damage and predict development of CIPN.

Methods: We conducted a prospective study in patients with breast cancer who were treated with a taxane-based CTX regimen. Study was approved by our institutional review board and registered on clinicaltrials.gov (NCT03365895). Patients who were eligible to get CTX with a taxane based regimen (paclitaxel or docetaxel) were included. Patients with prior exposure to neurotoxic CTX, significant peripheral neuropathy at baseline, or history of diabetes were excluded. All patients completed pre and post CTX MRI of bilateral leg and ankles and a self-reported Functional Assessment of Cancer Therapy/Gynecological Oncology Group neurotoxic questionnaire (FACT-NTX). Patients were diagnosed with developing symptomatic neuropathy if the absolute increase in their FACT-NTX score was ≥3 at post treatment evaluation.

Results: Twenty patients consented however 6 were ineligible. Fourteen patients completed all the study procedures. Median age of the evaluable patients was 53 years (33-72 years); 11/14 had paclitaxel CTX. For all patients, median baseline FACT-NTX score was significantly lower (2.5) than post treatment score (5.5) (p=0.009). Based on FACT-NTX score changes, 64% of patients developed symptomatic neuropathy. For all patients, the minimum FA values post-chemotherapy at mid-calf and ankle (0.42 and 0.41 respectively) are significantly lower than baseline (0.54 and 0.49 respectively, p=&lt;0.0001 at mid-calf, p=0.03 at ankle) indicating change in nerve structure with CTX. There was no significant change in mean ADC measurements at mid-calf and ankle pre CTX (1.21 and 1.17 respectively) versus post CTX (1.29 and 1.9 respectively, p=0.14 for mid-calf, p=0.9 at ankle). In patients who developed neuropathy, the median minimum FA value at mid-calf at baseline was lower compared to those who did not (p=0.016).

Conclusions: Our study highlights the use of measuring minimum FA value at the mid-calf and ankle to evaluate for CIPN. Our results indicate that minimum FA value decreased with CTX induced nerve damage and a lower baseline measurement is likely predictive of developing CIPN. This suggests that minimum FA value can be used as a non-invasive imaging biomarker to help predict those at risk for CIPN and potentially be used to implement prevention strategies. Additional clinical trials are warranted to further evaluate this promising predictive biomarker.

Citation Format: Hninyee Win, Lana Gimber, Jennifer Segar, Michele Chu, Sima Ehsani, Pavani Chalasani. Imaging predictors for development of chemotherapy induced peripheral neuropathy [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P3-08-27.

Abstract OT3-15-02: A randomized, double-blind, placebo-controlled study of 4-hydroxytamoxifen topical gel in women with mammographically dense breasts

Background: Tamoxifen uptake for risk reduction has remained low due to concerns about toxicity despite the efficacy and effectiveness data available. Studies of tamoxifen in the adjuvant and preventive setting have demonstrated that a decline in mammographic density (MD) of approximately 10% is consistently associated with better outcomes. Additionally, MD is one of the strongest independent predictors of breast cancer risk, apart from older age and BRCA1/2 mutation, among women. 4-hydroxytamoxifen topical gel (4-OHT) is a transdermal agent, shown in preliminary studies to be well-tolerated with similar decreases in Ki-67 to oral tamoxifen in presurgical DCIS studies and significant drug concentration in breast parenchyma but very low levels in the systemic circulation. This study examines changes in MD, a potential surrogate biomarker of prevention activity, as the primary endpoint for this one-year early-phase prevention trial using 4-OHT gel in high risk women.

Trial design: Multicenter, randomized, placebo-controlled study of 4-OHT gel (2mg per breast) versus placebo in 152 women with heterogeneously or extremely dense breast tissue for 12 months using standard of care imaging, stratified by enrollment site and baseline breast density category. The primary objective of this study is to evaluate the change in percent MD (using Cumulus software) from baseline to the week 52 in women applying 4 mg (2mg per breast) 4-OHT gel versus placebo. The secondary objectives are to compare the Cumulus vs Volpara breast density measurement methods; evaluate the percentage of women with lowering of BIRADS density; estimate percentage of women with ≥ 10% absolute decrease in quantitative MD percentage; explore patient reported experience assessed by BESS questionnaire; laboratory toxicity assessment (F VIII, vWB factor, SHBG, lipid profile); compare the 2D vs. 3D breast density measurement methods to estimate percent change in mammographic breast density; evaluate serum measurements of parent drug and related metabolite levels and factors related to 4-OHT exposures, such as IGF pathway members, CRP, estradiol, and 4-OHT; collect tissue for biomarkers (among women undergoing optional pre- and post-treatment biopsies); examine the persistence in change of mammographic density one year after 4-OHT vs. placebo gel application has stopped.

Eligibility criteria: Inclusion: Women age 40-69 years, or less than 40 years if 5-year breast cancer Gail risk is greater than/equal to 1.66%; heterogeneously or extremely dense breast tissue based on mammography. Exclusion: abnormal uterine bleeding, or prior diagnosis of endometrial hyperplasia, endometrial polyps, or endometrial cancer; prior use of SERMS and AIs, except for a maximum of 3 months and at least 12 months prior.

Statistical methods: Considering an attrition rate of 15%, 128 evaluable women are expected to have both baseline and 52-week measurements of percent MD. With 64 women in each group, there is 80% power to detect a decrease of 6% in the 4-OHT group versus 2% in the placebo group with a common standard deviation of 8% using a two-sided t-test with a significance level of 0.05. Study accrual: Activated January 2018, as of July 1, 2019, 92 patients have been recruited and 79 were randomized.

Citation Format: Banu K. Arun, Gretchen Gierach, Marion E Scoggins, Seema Khan, Sandra S Rao, Judy Garber, Sughra Raza, Nagi B. Kumar, Heather H Han, John Heine, Bethany Niell, Pavani Chalasani, Kimberly Fitzpatrick, Lee G Wilke, Amy Fowler, Heather C Beckwith, Carrie Mays, Saba Abutaseh, Lana Vornik, Oukseub Lee, Eileen Dimond, Marjorie Perloff, Diane Liu, J. Jack Lee, Powell Brown, Brandy Heckman-Stoddard. A randomized, double-blind, placebo-controlled study of 4-hydroxytamoxifen topical gel in women with mammographically dense breasts [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr OT3-15-02.

Abstract PD3-09: Sulindac reduces breast density and alters collagen alignment in patients on aromatase inhibitors

Background. Preclinical and observational evidence supports cancer prevention activity of non-steroidal anti-inflammatory drugs (NSAIDs) in the breast via suppression of prostaglandin E2 (PGE2) synthesis by cyclooxygenase-2 (COX2). Evidence includes linking of PGE2 to aromatase activity and estrogen synthesis in breast adipose tissue, as well as effects on collagen and breast density (BD). Methods. In an open-label trial, we evaluated the effect of the non-selective NSAID sulindac at 150 mg bid for 12 months on BD in 52 postmenopausal women taking adjuvant aromatase inhibitors (AIs) for breast cancer. BD was measured using a fat-water decomposition MRI based BD measure (MRD) previously shown to be more quantitative than mammographic density. A non-randomized observation cohort of 46 postmenopausal women on AI without NSAID use was conducted in parallel to assess the effect of AI on MRD over 12 months. Eligible participants were recruited at two study sites and included women with an intact, unaffected contralateral breast and BI-RADS ≥ 2. Each subject’s MRI_BD measures at baseline and at 6 and 12 months were included in linear mixed models for longitudinal data. Log-transformation was applied to the outcome of BD. Covariates included log-transformed baseline BD, time on AI, and baseline body mass index (BMI) and change in BMI. Breast tissue collagen fiber alignment for 30 women with paired breast biopsies, before and after 6 months on sulindac, was examined using Second-Harmonic Generation (SHG) microscopy and analysis of the distribution (histogram) of ‘straight’ fibers in three randomly selected areas of breast tissue. Straightness of individual fibers was calculated as the linear length of a fiber divided by the distance along the fiber. Results. Participants on sulindac intervention had a significant change in BD relative to baseline BD at 6 (p=0.05) and 12 months (p&lt;0.001). After adjusting for time on AI, baseline BMI and BMI change, the relative change in BD at 12 months from baseline BD was 10% lower (95% CI; -14.4, -5.4%) for women on sulindac. For the AI only group, no significant change from baseline BD was observed at 6 (p=0.50) or 12 months (p=0.17). The relative change in BD for the AI only group at 12 months was -3.5% (95% CI; -8.3, +1.6%). For women with baseline MRD_BD of ≥ 25%, the relative decrease in BD from baseline in the sulindac group was greater, at -16.3% (95% CI, -25.4, -6.2%). In contrast, there was no evidence for baseline BD effect on change in BD at 12 months in the AI only group whose baseline BD was ≥25% [-3.3% change at 12 mo (95% CI; -12.7, +7.1%)]. Exploratory analyses of collagen fiber alignment in the sulindac group at 6 months showed a significant decrease in straight collagen fibers (p=0.01). The decrease in collagen straightness correlated with a decrease in BD (rho=0.66, p=0.01). Conclusions. Twice daily 150 mg sulindac for 12 months in postmenopausal women on AIs was associated with a significant decrease in BD using MRD that was slightly higher for women with higher baseline BD. At the tissue level, the decrease in BD was associated with change in collagen straightness. No decrease in BD was observed in a non-randomized population of postmenopausal women on AI only therapy. These results suggest that sulindac decreases BD and may do so through effects on collagen alignment. Further investigation of sulindac for effects on BD, including synergy with AIs, for breast cancer prevention is indicated.

Citation Format: Patricia Thompson, Chuan Huang, Betsy Wertheim, Christina Preece, Jie Yang, Jessica Martinez, Denise Roe, Pavani Chalasani, Alison Stopeck. Sulindac reduces breast density and alters collagen alignment in patients on aromatase inhibitors [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr PD3-09.