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.

ANG1005, a Brain-Penetrating Peptide-Drug Conjugate, Shows Activity in Patients with Breast Cancer with Leptomeningeal Carcinomatosis and Recurrent Brain Metastases

PURPOSE

ANG1005, a novel taxane derivative, consists of three paclitaxel molecules covalently linked to Angiopep-2, designed to cross the blood-brain and blood-cerebrospinal barriers and to penetrate malignant cells via LRP1 transport system. Preclinical and clinical evidence of efficacy with ANG1005 has been previously shown.

PATIENTS AND METHODS

A multicenter, open-label phase II study in adult patients with measurable recurrent brain metastases from breast cancer (BCBM), with or without leptomeningeal carcinomatosis was conducted (n = 72 BCBM; n = 28 leptomeningeal carcinomatosis subset). ANG1005 was administered intravenously at 600 mg/m2 every 3 weeks. Tumor assessment was based on central nervous system (CNS) RECIST 1.1 for intracranial, and RECIST 1.1 for extracranial response. The primary endpoint was determination of intracranial objective response rate (iORR).

RESULTS

Median age was 47.5 years. Safety profile was similar to that of paclitaxel with myelosuppression as the predominating toxicity. Average number of prior CNS-directed therapies was 2.8 and 94% of the patients had prior taxane treatment. Patient benefit (stable disease or better) was seen in 77% (intracranial) and 86% (extracranial) of the evaluable patients, with iORR of 15% (investigator) or 8% (independent radiology facility [IRF] review). In the leptomeningeal carcinomatosis subset, 79% of the patients had intracranial disease control and estimated median overall survival of 8.0 months (95% CI, 5.4-9.4).

CONCLUSIONS

Even though the study preset rule for iORR per IRF was not met in this heavily pretreated population, a notable CNS and systemic treatment effect was seen in all patients including symptom improvement and prolonged overall survival compared to historical control for the subset of patients with leptomeningeal carcinomatosis (n = 28).

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.