Impact of COVID-19 on patients with metastatic breast cancer: REthink Access to Care and Treatment survey results

Aim: Patients with metastatic breast cancer (MBC) may be vulnerable to changes in healthcare management, safety standards and protocols that occurred during the COVID-19 pandemic. Materials & methods: The REthink Access to Care & Treatment (REACT) survey assessed USA-based patient perspectives on COVID-19-related impacts to their MBC treatment experience between 27 April 2021 and 17 August 2021. Results: Participants (n = 341; 98.5% females, mean age 50.8 years) reported that overall oncology treatment quality was maintained during the pandemic. Delayed/canceled diagnostic imaging was reported by 44.9% of participants while telemedicine uptake was high among participants (80%). Conclusion: Overall, MBC care was minimally affected by the pandemic, possibly due to the expanded use of telemedicine, informing MBC management for future public health emergencies.

Lasofoxifene versus fulvestrant for ER+/HER2- metastatic breast cancer with an ESR1 mutation: results from the randomized, phase II ELAINE 1 trial

BACKGROUND

Acquired estrogen receptor alpha (ER/ESR1) mutations commonly cause endocrine resistance in ER+ metastatic breast cancer (mBC). Lasofoxifene, a novel selective ER modulator, stabilizes an antagonist conformation of wild-type and ESR1-mutated ER-ligand binding domains, and has antitumor activity in ESR1-mutated xenografts.

PATIENTS AND METHODS

In this open-label, randomized, phase II, multicenter, ELAINE 1 study (NCT03781063), we randomized women with ESR1-mutated, ER+/human epidermal growth factor receptor 2 negative (HER2-) mBC that had progressed on an aromatase inhibitor (AI) plus a cyclin-dependent kinase 4/6 inhibitor (CDK4/6i) to oral lasofoxifene 5 mg daily or IM fulvestrant 500 mg (days 1, 15, and 29, and then every 4 weeks) until disease progression/toxicity. The primary endpoint was progression-free survival (PFS); secondary endpoints were safety/tolerability.

RESULTS

A total of 103 patients received lasofoxifene (n = 52) or fulvestrant (n = 51). The most current efficacy analysis showed that lasofoxifene did not significantly prolong median PFS compared with fulvestrant: 24.2 weeks (∼5.6 months) versus 16.2 weeks (∼3.7 months; P = 0.138); hazard ratio 0.699 (95% confidence interval 0.434-1.125). However, PFS and other clinical endpoints numerically favored lasofoxifene: clinical benefit rate (36.5% versus 21.6%; P = 0.117), objective response rate [13.2% (including a complete response in one lasofoxifene-treated patient) versus 2.9%; P = 0.124], and 6-month (53.4% versus 37.9%) and 12-month (30.7% versus 14.1%) PFS rates. Most common treatment-emergent adverse events with lasofoxifene were nausea, fatigue, arthralgia, and hot flushes. One death occurred in the fulvestrant arm. Circulating tumor DNA ESR1 mutant allele fraction (MAF) decreased from baseline to week 8 in 82.9% of evaluable lasofoxifene-treated versus 61.5% of fulvestrant-treated patients.

CONCLUSIONS

Lasofoxifene demonstrated encouraging antitumor activity versus fulvestrant and was well tolerated in patients with ESR1-mutated, endocrine-resistant mBC following progression on AI plus CDK4/6i. Consistent with target engagement, lasofoxifene reduced ESR1 MAF, and to a greater extent than fulvestrant. Lasofoxifene may be a promising targeted treatment for patients with ESR1-mutated mBC and warrants further investigation.

Germline BRCA-Mutated HER2-Negative Advanced Breast Cancer: Overcoming Challenges in Genetic Testing and Clinical Considerations When Using Talazoparib

Genetic testing is essential to the diagnosis and management of patients with breast cancer. For example, women who carry mutations in BRCA1/2 genes have an increased lifetime risk of breast cancer and the presence of these mutations may sensitize the patient to treatment with poly(ADP-ribose) polymerase (PARP) inhibitors. Two PARP inhibitors are approved by the US Food and Drug Administration for patients with germline BRCA-mutated advanced breast cancer (olaparib and talazoparib). The NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) for Breast Cancer (Version 2.2023) recommend that all patients with recurrent or metastatic breast cancer (mBC) be assessed for the presence of germline BRCA1/2 mutations. However, many women eligible for genetic testing do not receive it. Here, we provide our perspectives on both the importance of genetic testing and the challenges patients and community clinicians may face when trying to access genetic testing. We also present a hypothetical case study involving a female patient with germline BRCA-mutated human epidermal growth factor receptor 2 (HER2)-negative mBC to highlight potential clinical considerations on the use of talazoparib, including the decision to initiate therapy, dosing considerations, potential drug-drug interactions, and managing side effects. This case illustrates the benefits of a multidisciplinary approach to managing patients with mBC and involving the patient in the decision-making process. This patient case is fictional and does not represent events or a response from an actual patient; this fictional case is for educational purposes only.

Margetuximab Versus Trastuzumab in Patients With Previously Treated HER2-Positive Advanced Breast Cancer (SOPHIA): Final Overall Survival Results From a Randomized Phase 3 Trial

Clinical trials frequently include multiple end points that mature at different times. The initial report, typically based on the primary end point, may be published when key planned co-primary or secondary analyses are not yet available. Clinical Trial Updates provide an opportunity to disseminate additional results from studies, published in JCO or elsewhere, for which the primary end point has already been reported.Final overall survival (OS) in SOPHIA (ClinicalTrials.gov identifier: NCT02492711), a study of margetuximab versus trastuzumab, both with chemotherapy, in patients with previously treated human epidermal growth factor receptor 2-positive advanced breast cancer, is reported with updated safety. Overall, 536 patients in the intention-to-treat population were randomly assigned to margetuximab (15 mg/kg intravenously once every 3 weeks; n = 266) plus chemotherapy or trastuzumab (6 mg/kg intravenously once every 3 weeks after a loading dose of 8 mg/kg; n = 270) plus chemotherapy. Primary end points were progression-free survival, previously reported, and OS. Final OS analysis was triggered by 385 prespecified events. The median OS was 21.6 months (95% CI, 18.89 to 25.07) with margetuximab versus 21.9 months (95% CI, 18.69 to 24.18) with trastuzumab (hazard ratio [HR], 0.95; 95% CI, 0.77 to 1.17; P = .620). Preplanned, exploratory analysis of CD16A genotyping suggested a possible improvement in OS for margetuximab in CD16A-158FF patients versus trastuzumab (median OS, 23.6 v 19.2 months; HR, 0.72; 95% CI, 0.52 to 1.00) and a possible improvement in OS for trastuzumab in CD16A-158VV patients versus margetuximab (median OS, 31.1 v 22.0 months; HR, 1.77; 95% CI, 1.01 to 3.12). Margetuximab safety was comparable with trastuzumab. Final overall OS analysis did not demonstrate margetuximab advantage over trastuzumab. Margetuximab studies in patients with human epidermal growth factor receptor 2-positive breast cancer with different CD16A allelic variants are warranted.

Association of Autologous Tumor Lysate-Loaded Dendritic Cell Vaccination With Extension of Survival Among Patients With Newly Diagnosed and Recurrent Glioblastoma: A Phase 3 Prospective Externally Controlled Cohort Trial

Importance

Glioblastoma is the most lethal primary brain cancer. Clinical outcomes for glioblastoma remain poor, and new treatments are needed.

Objective

To investigate whether adding autologous tumor lysate-loaded dendritic cell vaccine (DCVax-L) to standard of care (SOC) extends survival among patients with glioblastoma.

Design, Setting, and Participants

This phase 3, prospective, externally controlled nonrandomized trial compared overall survival (OS) in patients with newly diagnosed glioblastoma (nGBM) and recurrent glioblastoma (rGBM) treated with DCVax-L plus SOC vs contemporaneous matched external control patients treated with SOC. This international, multicenter trial was conducted at 94 sites in 4 countries from August 2007 to November 2015. Data analysis was conducted from October 2020 to September 2021.

Interventions

The active treatment was DCVax-L plus SOC temozolomide. The nGBM external control patients received SOC temozolomide and placebo; the rGBM external controls received approved rGBM therapies.

Main Outcomes and Measures

The primary and secondary end points compared overall survival (OS) in nGBM and rGBM, respectively, with contemporaneous matched external control populations from the control groups of other formal randomized clinical trials.

Results

A total of 331 patients were enrolled in the trial, with 232 randomized to the DCVax-L group and 99 to the placebo group. Median OS (mOS) for the 232 patients with nGBM receiving DCVax-L was 19.3 (95% CI, 17.5-21.3) months from randomization (22.4 months from surgery) vs 16.5 (95% CI, 16.0-17.5) months from randomization in control patients (HR = 0.80; 98% CI, 0.00-0.94; P = .002). Survival at 48 months from randomization was 15.7% vs 9.9%, and at 60 months, it was 13.0% vs 5.7%. For 64 patients with rGBM receiving DCVax-L, mOS was 13.2 (95% CI, 9.7-16.8) months from relapse vs 7.8 (95% CI, 7.2-8.2) months among control patients (HR, 0.58; 98% CI, 0.00-0.76; P < .001). Survival at 24 and 30 months after recurrence was 20.7% vs 9.6% and 11.1% vs 5.1%, respectively. Survival was improved in patients with nGBM with methylated MGMT receiving DCVax-L compared with external control patients (HR, 0.74; 98% CI, 0.55-1.00; P = .03).

Conclusions and Relevance

In this study, adding DCVax-L to SOC resulted in clinically meaningful and statistically significant extension of survival for patients with both nGBM and rGBM compared with contemporaneous, matched external controls who received SOC alone.

Trial Registration

ClinicalTrials.gov Identifier: NCT00045968.

Expert consensus recommendations for managing hyperglycemia and rash in patients with PIK3CA-mutated, hormone receptor-positive (HR+), human epidermal growth factor receptor 2-negative (HER2–) advanced breast cancer (ABC) treated with alpelisib (ALP)

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Background: ALP is a PI3Kα inhibitor and degrader approved with fulvestrant for the treatment (tx) of patients (pts) with PIK3CA-mutated, HR+, HER2– ABC. Hyperglycemia (HG) and rash are expected adverse events with ALP tx and remain a challenge for physicians and pts. Management guidance is primarily based on clinical trial experience, which is not necessarily reflective of real-world pts. Here we report guidance for optimizing prevention and management of HG and rash in pts taking ALP based on an integrated Delphi panel, a systematic, validated approach to organize consensus from experts in the absence of definitive evidence. Methods: Two modified Delphi panels were conducted, focusing on HG and rash, respectively. Each panel included 4 oncologists, 4 endocrinologists or dermatologists, 1 clinical pharmacist, and 1 pt advocate. Experts were asked to rate appropriateness of 908 interventions for HG and 348 for rash on hypothetical pt scenarios on a 1 (highly inappropriate) to 9 (highly appropriate) scale. Results were reviewed at virtual meetings, after which experts repeated the rating. The level of agreement or disagreement was determined using the median scores and dispersion from the final rating, and this level of agreement was used to develop consensus statements and tx algorithms. Results: Per the HG panel, (a) ALP tx is appropriate in individuals with HbA1c 6.5% to < 8% with a pre-tx endocrinology consult; (b) low carbohydrate diet is appropriate in all pts starting ALP; (c) prophylactic metformin is appropriate in pts with baseline HbA1c 5.7%-6.4%; may also be appropriate in pts with HbA1c < 5.7%; (d) after metformin, an SGLT2 inhibitor or a thiazolidinedione is an appropriate second-/third-line anti-HG agent (or first-line in metformin-intolerant pts), while insulin is not. Per the rash panel, (a) prophylactic nonsedating (NS) H1 antihistamines (standard dose) are appropriate for all pts; (b) starting/escalating NS H1 antihistamines and topical steroids (TS) is the preferred first step for managing rash; (c) it is appropriate to add, but not replace with, a sedating H1 antihistamine, if response to high-dose, NS option is inadequate, and to add an H2 antihistamine if response is still inadequate; (d) it is appropriate to hold ALP and start oral corticosteroids (OCS) if rash affects > 30% body surface area and is recurrent or has moderate/severe symptoms; (e) if angioedema is present, it is appropriate to either hold ALP and start OCS, or permanently discontinue ALP tx. Conclusions: Until further evidence is available, these expert recommendations provide guidance on prevention and management of HG and rash related to ALP tx in routine clinical practice.

Phase 1b/2 study of ladiratuzumab vedotin (LV) in combination with pembrolizumab for first-line treatment of triple-negative breast cancer (SGNLVA-002, trial in progress)

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Background: Patients with metastatic triple-negative breast cancer (mTNBC) have a poor prognosis. Treatment combinations of anti-programmed death ligand 1 (anti–PD-L1) agents with chemotherapy have shown promise in mTNBC. LV is an investigational antibody–drug conjugate directed to LIV-1, a protein highly expressed on breast cancer cells, via a humanized IgG1 monoclonal antibody conjugated to monomethyl auristatin E (MMAE) by a protease-cleavable linker. LIV-1–mediated delivery of MMAE disrupts microtubules and induces cell cycle arrest and apoptosis. LV has also been shown to drive immunogenic cell death (ICD) to elicit an immune response. LV + pembrolizumab may result in synergistic activity through LV-induced ICD, creating a microenvironment favorable for enhanced anti–PD-L1 activity. Preliminary results show LV delivered once every 3 weeks (Q3W) + pembrolizumab was tolerable with encouraging antitumor activity in patients with mTNBC (Han 2019). Additionally, interim results of weekly LV monotherapy at doses up to 1.5 mg/kg were clinically active and generally well tolerated (Tsai 2021). Based on pharmacokinetic and pharmacodynamic modeling and simulation analysis, an intermittent LV + pembrolizumab dosing regimen is being evaluated to further enhance efficacy and improve the tolerability profile. Due to an unmet medical need for patients with mTNBC who are PD-L1 low or negative, Part D will focus on this patient population. Methods: SGNLVA-002 (NCT03310957) is an ongoing global single-arm, open-label phase 1b/2 study of LV + pembrolizumab as 1L therapy for patients with unresectable locally advanced/mTNBC. Part D is currently enrolling ̃40 patients. Eligible patients must have advanced disease with no prior cytotoxic/anti–PD-L1 treatment, PD-L1 combined positive score < 10, measurable disease per RECIST v1.1 and an ECOG score ≤1. Patients with Grade ≥2 pre-existing neuropathy or active central nervous system metastases are not permitted. Patients will receive LV at 1.5 mg/kg on Days 1 and 8 plus pembrolizumab 200 mg on Day 1 Q3W. The primary objectives are to evaluate the safety/tolerability and objective response rate of LV + pembrolizumab. Secondary objectives include duration of response, disease control rate, progression-free survival, and overall survival. Safety and efficacy endpoints will be summarized with descriptive statistics. Global enrollment is ongoing in the US, EU, and Asia. Clinical trial information: NCT03310957.

Dual tissue and plasma testing to improve detection of actionable variants in patients with solid cancers

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Background: Next generation sequencing (NGS) of tumor tissue and plasma (circulating tumor DNA [ctDNA]) are used clinically to identify actionable genomic alterations, with implications for treatment selection and disease surveillance. Early studies have observed that solid tumor tissue and ctDNA testing may capture both overlapping and complementary alterations. Using the Tempus database, we examined whether dual tissue and ctDNA testing, “dual testing”, improved identification of actionable variants compared with either modality alone. Methods: We used Tempus Lens to retrospectively analyze 3153 de-identified stage 4 patients (breast [N = 644], colorectal [N = 841], non-small cell lung cancer (NSCLC) [N = 1232], and prostate [N = 436]). Each patient had dual testing—Tempus xF (ctDNA, 105 panel genes) and Tempus xT (tumor tissue, 595-648 panel genes), representing 6306 total samples. Samples were defined as concurrent if biopsied ≤30 days apart and longitudinal if plasma was collected between 31–365 days after tissue biopsy. All analyses were limited to single nucleotide variants and insertions/deletions that met the limit of detection criteria for both assays (104 genes). Indication matched actionable variants were defined by OncoKB Level 1 and 2 evidence, or R1 within both xF and xT (13 genes). Results: Of the 3153 patients with dual testing, 37% (1168) had actionable variants identified by at least one test. 94% (1100/1168) of these patients had variants identified via solid tumor profiling alone, 73% (856) had variants identified via ctDNA profiling alone, and 64% (745) had perfectly concordant variants. Thus, dual testing identified additional variants in 36% (423/1168) of these patients compared to any singular test. Of the 423 patients who had additional actionable alterations discovered through dual testing, ctDNA revealed unique alterations—which were not found in solid tissue testing—in 22% (95/423) of patients. Of these patients, 72% (68/95) had all actionable variants identified solely from ctDNA. Of the 251 patients with additional alterations identified by concurrent dual testing, 24% (61/251) had unique alterations identified in plasma. Similarly, of the 172 patients with additional alterations identified by longitudinal dual testing, 20% (34/172) had unique alterations identified in ctDNA alone. Conclusions: In the largest study of its kind, we show that dual tumor tissue and ctDNA testing—with samples collected either concurrently or longitudinally—identified more patients with actionable alterations than single modality testing alone and therefore should be considered as part of routine NGS testing. Additional studies to explore the genetic and intra-patient tumor heterogeneity of these variants as well as the impact of time between tissue and plasma sampling assessments and implications for timing of therapeutic recommendations are underway.

Treatment of alpelisib induced hyperglycemia with sodium-glucose cotransporter-2 inhibitors: A single institution experience

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Background: PIK3CA mutations occur in about 40% of patients with HR+/HER2- breast cancer. The phase III SOLAR-1 trial demonstrated prolonged progression-free survival with alpelisib and fulvestrant compared to fulvestrant alone among patients with HR+/HER2-/ PIK3CA mutant advanced breast cancer previously treated with endocrine therapy. Hyperglycemia was seen in 64% of patients treated with alpelisib and fulvestrant and was treated with metformin. Inhibition of PI3Kα leads to an on-target effect of hyperglycemia and a secondary hyperinsulinemia. This rebound hyperinsulinemia may lead to escape PI3K pathway activation in breast cancer progression via the insulin and IGF1pathways. Concurrent administration of SGLT2 inhibitors may abrogate the PI3K pathway activation effect and delay disease progression. This study reports time on treatment with alpelisib and PFS among patients who received an SGLT2 inhibitor with alpelisib. Methods: A retrospective review of all metastatic breast cancer patients treated with alpelisib was completed from 8/2019 to 5/2021 at the Saint Luke’s Koontz Center for Advanced Breast Cancer. Results: This review included 22 female patients, 11 received an SGLT2 inhibitor for treatment related hyperglycemia (A+SGLT group) and 11 who received metformin/other diabetic agents (A group). Baseline characteristics were not significantly different between the two groups: median age 63, BMI of 29.1, hemoglobin A1C of 6.3 and fasting blood glucose of 119.1mg/dl. PIK3CA mutations included H1047X (40.9%), E545X (31.8%), E542K (13.6%), other (13.6%). The median number of prior treatments for MBC was 3 (range 1-5). Prior treatments included aromatase inhibitors: 100%, fulvestrant: 77%, CDK 4/6 inhibitors: 82%, everolimus: 32% and chemotherapy: 68%. Hyperglycemia grade 2+ was seen in 72.7% of patients. There were no significant differences between the two groups for emergency room visits, hospitalizations, or endocrinology referrals related to hyperglycemia. Median time to initiation of an SGLT2 inhibitor was 13 days following the first dose of alpelisib. PFS was longer in the A+SGLT compared with the A group with a median time to progression of 6.1 months and 3.9 months respectively (HR 0.51; 95% CI 0.16 to 1.63; p = 0.39). Time on treatment was significantly longer for A+SGLT group compared with the A group, with a median time on treatment of 5.8 months, compared with 3.0 months (HR 0.32; 95% CI 0.11 to 0.92; p = 0.03). The primary reason for discontinuation of alpelisb was disease progression in 73%, with no statistically significant difference in the reason for discontinuation between the groups. Conclusions: This study supports a potential clinical benefit of an SGLT inhibitor along with alpelisib in allowing for a longer time on treatment, without significant adverse events. It also suggests a possible favorable impact on PFS for the combination.

Utilizing an innovative digital collaboration tool to impact shared decision making, health equity and trust with a focus on advance care planning for patients with metastatic breast cancer

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Background: Advance care planning (ACP) has been associated with improved quality of life, increased use of hospice and palliative care, and less use of extreme treatments close to death. These conversations often do not occur and documentation rates of ACP in oncology patients have been as low as 10%, with rates of documentation increasing between 30-40% in intervention studies. The present study aimed to examine the effectiveness of an online Advance Care Appointment Companion (ACAC) collaboration tool to improve communication and elevate trust between MBC patients and their oncologist and increase completion rates of ACP documents. Methods: Data were collected from 48 patients with mean age of 66.9 years (SD = 6.97) with MBC during their medical oncology appointments (Time 1) and three months later (Time 2) at the Koontz Center for Advanced Breast Cancer. At Time 1, patients were enrolled on the ACAC platform and then completed questions in the clinic or at home about completion status of a healthcare directive and durable power of attorney (DPOA) for healthcare, comfort in discussing ACP with their care team and loved ones, and goals of care at end of life. A summary of these responses with a provider prompt script was securely sent to the oncologist prior to each appointment and used to discuss ACP over the three-month study period. Descriptive statistics, t-tests, McNemar-Bowker and McNemar’s tests were conducted to examine changes in rates of ACP document completion, patient reported levels of comfort in discussing ACP, and quality of life preferences. Results: The study included a diverse sample of female MBC patients including 79% White, 19% Black/African American, 2% Mixed Race; 6% less than a high school degree, 17% high school or GED, 19% some college, and 58% associate’s degree or above. Results showed a significant increase in completion of a healthcare directive (Time 1 = 10.4%, Time 2 = 37.5%, p < .01) and DPOA (Time 1 = 31.5%, Time 2 = 56.3%, p < .01) and improved comfort discussing ACP with their care team (p < .01) and loved ones (p < .01) from baseline to follow-up. Significantly more patients reported that they would not want CPR (p < .05) at follow-up and all of these patients had reported that they were unsure at baseline. On average, ACP conversations during medical appointment took 5 minutes to discuss. Conclusions: Results show that the ACAC is an inclusive solution which provides equitable access to patients. This tool facilitates enhanced patient provider communication and assists patients with MBC in finalizing decisions regarding their goals of care, leading to increased completion and proper submission of ACP documentation. Future research should examine how the ACAC can decrease financial toxicity, utilize internal resources, and address social determinants of health.

Abstract P1-17-03: H3B-6545 in combination with palbociclib in women with metastatic estrogen receptor-positive (ER+), human epidermal growth factor receptor 2 (HER2)-negative breast cancer, phase 1b study

Background: H3B-6545, a novel Selective ERα Covalent Antagonist (SERCA), inactivates both mutant and wild-type ERα by targeting cysteine 530 and enforcing antagonist conformation. It demonstrated a manageable safety profile and single-agent antitumor activity in heavily pretreated ER+, HER2- mBC patients (pts) (Hamilton et al, ASCO, 2021). Methods: The study aims at determining the recommended phase II doses of the combination of H3B-6545 and palbociclib in pts with ER+, HER2- mBC. Other endpoints include safety, pharmacokinetics, and preliminary efficacy. The escalation phase enrolls pts with at least 2 prior therapies in the metastatic setting. Up to one prior chemotherapy and up to one prior CDK4/6 inhibitor are allowed. Each cohort enrolled 6 pts to ensure availability of sufficient PK data. During the first cycle, H3B-6545 was added to palbociclib on day 9. Dose-limiting toxicities (DLTs) were assessed during the first 28 days starting from the 1st day of adding H3B-6545 to palbociclib (cycle 1 day 9 to cycle 2 day 8). Both drugs were started on day 1 of each of the subsequent cycles. Results: As of June 15, 2021, 14 pts were enrolled: 7 in Cohort 1 (H3B-6545 300 mg QD and palbociclib 100 mg QD) and 7 in Cohort 2 (H3B-6545 300 mg QD and palbociclib 125 mg QD). Median age was 61 years (range: 28-75 years), ECOG performance status was 0 in 7 pts (50%) and 1 in 7 pts (50%) and 9 pts (64%) had lung and/or liver metastases. Median number of prior therapies in the metastatic setting was 3 (range: 1-6). Prior therapy in the metastatic setting included fulvestrant (93%), CDK4/6 inhibitors (79%), aromatase inhibitors (64%), and chemotherapy (29%). One pt in each Cohort was not evaluable for dose limiting toxicity (DLT) assessment and no DLTs were observed in the first 2 Cohorts. Seven pts discontinued study treatment because of progression and 1 pt discontinued due to diagnosis of a second primary cancer during the first cycle. Non-hematological grade 2 or higher adverse events (AE), irrespective of causality, reported in ≥2 pts were: nausea, vomiting, abdominal pain, and bone pain, each observed in 2 pts (14%). Gr. 1 and 2 sinus bradycardia were reported in 6 (43%) and 1 pts (7%), respectively. One pt (7%) had grade 1 QT prolongation. No grade 4 AEs or treatment-related deaths were reported. For hematology and chemistry laboratory abnormalities: gr. 3 and 4 neutropenia in 7 pts (50%) and 2 pts (14%), respectively, gr. 3 thrombocytopenia in 1 pt (7%), gr. 3 anemia in 2 pts (14%). Grade 2 decrease in estimated glomerular filtration rate was observed in 7 pts (50%), all reported irrespective of causality. Co-administration of palbociclib had no meaningful impact on H3B-6545 exposure (15% and 21% increase in geometric means of AUC and Cmax, respectively). Co-administration of H3B-6545 modestly increased palbociclib exposure (49% and 36% increase in geometric means of AUC and Cmax, respectively). Among 6 response-evaluable pts in Cohort 1, 2 pts (33%) had confirmed partial responses and 4 pts (67%) had stable disease. Both responding pts received prior therapy with a CDK4/6 inhibitor and fulvestrant. Cohort 2 efficacy data is not yet mature. Recruitment is currently ongoing in Cohort 3 (H3B-6545 450 mg QD and palbociclib 125 mg QD). Conclusions: The combination of H3B-6545 (up to 300 mg dose) and palbociclib (up to 125 mg dose) was well-tolerated and demonstrated preliminary anti-tumor activity in heavily pretreated pts with ER+, HER2- mBC. ClinicalTrials.gov Identifier: NCT04288089.

Citation Format: Stephen Johnston, Timothy J Pluard, Judy S Wang, Erika P Hamilton, Dejan Juric, Catherine R Scholz, Elizabeth Hnitecki, Sara Dar, Lei Gao, Lisa Cantagallo, Manav Korpal, Jianjun Alan Xiao, Lihua Yu, Tarek Sahmoud, Antonio Gualberto. H3B-6545 in combination with palbociclib in women with metastatic estrogen receptor-positive (ER+), human epidermal growth factor receptor 2 (HER2)-negative breast cancer, phase 1b study [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 P1-17-03.

Abstract P5-15-03: The effectiveness of an advance care appointment companion to increase completion of advance care planning among patients with metastatic breast cancer

Previous research has demonstrated that patients express a desire to discuss advance care planning (ACP). ACP has been associated with numerous positive outcomes including improved patient satisfaction, improved quality of life in terminal illness, and better psychological outcomes. Additionally, ACP has been related to peace of mind that wishes will be followed, less hospital re-admissions, and less use of extreme treatments close to death. Furthermore, it has been linked to increased use of hospice and palliative care and increased concordance between preferred care and the care delivered. However, despite the documented benefit of ACP, these conversations often do not occur due to discomfort with the topic or are communicated inadequately. Documentation rates of ACP in oncology patients have been as low as 10%, with rates of documentation increasing between 30-40% in intervention studies. Specific to women with metastatic breast cancer (MBC), one study found that 66% had written advance directives, but providers were only aware of these in 14% of the cases. Thus, the present study aimed to examine the effectiveness of an online Advance Care Appointment Companion (ACAC) decision-support tool to improve ACP communication between MBC patients and their oncologist and increase completion rates of ACP documents. Data were collected from 68 patients with MBC during their medical oncology appointments (Time 1) and three months later (Time 2) at the Koontz Center for Advanced Breast Cancer. At their Time 1 clinic visit, patients were introduced to and enrolled on the ACAC platform and then completed questions in the clinic or at home about completion status of a healthcare directive and durable power of attorney (DPOA) for healthcare, comfort in discussing ACP with their care team and loved ones, goals of care at end of life, and discussion topics about ACP for upcoming visits. A summary of these responses with a provider prompt script was securely sent to the oncologist prior to each subsequent appointment over the three-month study period. The oncologist used this summary and scripting to help navigate ACP conversations during each appointment. Descriptive statistics and McNemar’s test were conducted to examine changes in rates of ACP document completion and patient reported levels of comfort in discussing ACP. Majority of the sample was female (n=68, 100%), white (n=57, 84%), married (n=36, 53%), with a mean age of 64 years. At baseline, 41% of patients reported having a completed healthcare directive and 49% reported having a completed DPOA for healthcare, but only 12% had a healthcare directive and 24% had a DPOA in their electronic medical record (EMR). To-date, 35% (n=24) have a healthcare directive and 47% (n=32) have a notarized DPOA in their EMR; McNemar’s test showed a significant increase in the proportion of patients who completed ACP documents at Time 2 (p&lt; .001). At baseline, 74% of patients reported feeling comfortable discussing ACP with their care team and 69% reported feeling comfortable discussing ACP with their loved ones. Of note, 35% reported that they were unsure if they would want artificial nutrition, 37% reported they were unsure if they would want dialysis, and 37% reported that they were unsure if they would want resuscitation in the event that their heart stops. On average, ACP conversations during medical appointments took 5 minutes to discuss. Preliminary results suggest that the ACAC is an effective tool to facilitate discussion about ACP, resulting in significantly increased completed ACP documents in patient’s medical records. Assessment of patient-reported outcomes on comfort with discussing ACP and goals of care at Time 2 is ongoing. Results also revealed the potential for this tool to help foster communication about the intricacies of ACP as a large portion of patients reported that they were unsure about decisions that need to be made about end of life care.

Citation Format: Kadie M Harry, Cathy E Mitchell, Loic Nijiakin, Arabella Sykes, Timothy J Pluard. The effectiveness of an advance care appointment companion to increase completion of advance care planning among patients with metastatic 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 P5-15-03.

Trilaciclib Prior to Chemotherapy in Patients with Metastatic Triple-Negative Breast Cancer: Final Efficacy and Subgroup Analysis from a Randomized Phase II Study

PURPOSE

We report final antitumor efficacy results from a phase II study of trilaciclib, an intravenous cyclin-dependent kinase 4/6 (CDK4/6) inhibitor, administered prior to gemcitabine plus carboplatin (GCb) in patients with metastatic triple-negative breast cancer (NCT02978716).

PATIENTS AND METHODS

Patients were randomized (1:1:1) to group 1 [GCb (days 1, 8); n = 34], group 2 [trilaciclib prior to GCb (days 1, 8); n = 33], or group 3 [trilaciclib (days 1, 8) and trilaciclib prior to GCb (days 2, 9); n = 35]. Subgroup analyses were performed according to CDK4/6 dependence, level of programmed death-ligand 1 (PD-L1) expression, and RNA-based immune signatures using proportional hazards regression. T-cell receptor (TCR) β CDR3 regions were amplified and sequenced to identify, quantify, and compare the abundance of each unique TCRβ CDR3 at baseline and on treatment.

RESULTS

Median overall survival (OS) was 12.6 months in group 1, not reached in group 2 (HR = 0.31; P = 0.0016), 17.8 months in group 3 (HR = 0.40; P = 0.0004), and 19.8 months in groups 2 and 3 combined (HR = 0.37; P < 0.0001). Efficacy outcomes were comparable regardless of cancer CDK4/6 dependence status and immune signatures. Administering trilaciclib prior to GCb prolonged OS irrespective of PD-L1 status but had greater benefit in the PD-L1-positive population. T-cell activation was enhanced in patients receiving trilaciclib.

CONCLUSIONS

Administering trilaciclib prior to GCb enhanced antitumor efficacy, with significant improvements in OS. Efficacy outcomes in immunologic subgroups and enhancements in T-cell activation suggest these improvements may be mediated via immunologic mechanisms.

The phase II MutHER study of neratinib alone and in combination with fulvestrant in HER2 mutated, non-amplified metastatic breast cancer

PURPOSE

HER2 mutations (HER2^mut) induce endocrine resistance in estrogen receptor positive (ER+) breast cancer.

EXPERIMENTAL DESIGN

In this single arm multi-cohort phase II trial, we evaluated the efficacy of neratinib plus fulvestrant in patients with ER+/HER2^mut, HER2-non-amplified metastatic breast cancer (MBC) in the fulvestrant-treated (n=24) or fulvestrant-naïve cohort (n=11). Patients with ER-negative/HER2^mut MBC received neratinib monotherapy in an exploratory ER- cohort (n=5).

RESULTS

The clinical benefit rate (CBR: 95% CI) was 38% (18-62%), 30% (7-65%), and 25% (1-81%) in the fulvestrant-treated, fulvestrant-naïve, and ER- cohort, respectively. Adding trastuzumab at progression in 5 patients resulted in 3 partial responses and 1 stable disease {greater than or equal to}24 weeks. CBR appeared positively associated with lobular histology and negatively associated with HER2 L755 alterations. Acquired HER2^mut were detected in 5 of 23 patients at progression.

CONCLUSION

Neratinib and fulvestrant is active for ER+/HER2^mut MBC. Our data supports further evaluation of dual HER2 blockade for the treatment of HER2^mut MBC.

Phase I/II study of H3B-6545, a novel selective estrogen receptor covalent antagonist (SERCA), in estrogen receptor positive (ER+), human epidermal growth factor receptor 2 negative (HER2-) advanced breast cancer

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Background: H3B-6545, a selective, small molecule covalent antagonist of ERα demonstrated preclinical and preliminary clinical activity against ER+ breast cancer (Hamilton EP, SABCS, 2020). This study evaluated the activity and tolerability of H3B-6545 in patients (pts) with metastatic ER+, HER2-, breast cancer refractory to endocrine therapy. Methods: Patients received H3B-6545 once daily at the recommended phase II dose of 450 mg. The primary objective of the phase II is to estimate the objective response rate (ORR), progression-free survival (PFS), clinical benefit rate (CBR) and secondary objectives include safety. Results: 83 pts were treated with 450 mg in the phase II part of the trial. Additionally, 11 pts were treated with 450 mg in the phase I part of the trial and are included in this analysis. Median age was 62 years (range: 38 to 87 years), 81% had liver and/or lung metastases, and the median number of prior therapies for metastatic disease was 3 (range: 1 to 8). Prior CDK4/6 inhibitors, aromatase inhibitors, fulvestrant, and chemotherapy were received by 85%, 80%, 72%, and 50% of the pts, respectively. 58 pts (62%) had detectable ESR1 mutations in liquid biopsies, including 10 (11%) and 19 pts (20%) who had clonal Y537S and clonal D538G mutation, respectively. As of January 29, 2021, grade (gr) 2 or higher adverse events (AE) reported in ≥10% were anemia (19%), fatigue (16%), nausea (17%), and diarrhea (12%). Laboratory gr 2 or higher abnormalities reported in ≥10% pts were creatinine clearance decrease (38%), hemoglobin decrease (37%), bilirubin increase (12%), ALT increase (14%), AST increase (13%), and creatinine increase (11%). AE of gr 1 sinus bradycardia (asymptomatic) was reported in 34% and gr 2 (symptomatic, no intervention needed) was reported in 5%. Gr 2 and 3 QTcF prolongation were reported in 2 and 3 pts, respectively. There were no treatment-related deaths. Efficacy estimates are presented in the table below. Responses were observed in heavily pretreated pts, pts with visceral metastases and in pts who received prior fulvestrant, CDK4/6 inhibitor, and/or chemotherapy in the metastatic setting. Conclusions: H3B-6545 has a manageable safety profile and demonstrated single-agent anti-tumor activity in heavily pretreated ER+, HER2- mBC patients. Clinical activity was observed in pts with ESR1 mutations. Clinical trial information: NCT03250676 .[Table: see text]

Phase 1b study of H3B-6545 in combination with palbociclib in women with metastatic estrogen receptor–positive (ER+), human epidermal growth factor receptor 2 (HER2)-negative breast cancer

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Background: H3B-6545, a highly Selective ERα Covalent Antagonist (SERCA), inactivates both wild-type and mutant ERα by targeting cysteine 530 and enforcing a unique antagonist conformation. At the dose of 450 mg daily, H3B-6545 has a manageable safety profile and demonstrated preliminary single-agent antitumor activity in heavily pretreated ER+, HER2- mBC patients (Hamilton et al, San Antonio Breast Cancer Symposium, 2020). Methods: The study evaluates the safety, pharmacokinetics (PK), and efficacy of H3B-6545 in combination with palbociclib in patients with ER+, HER2- metastatic breast cancer (MBC). The escalation phase enrolls patients with 2 or more prior therapies in the metastatic setting. Up to one prior chemotherapy and up to one prior CDK4/6 inhibitor were allowed. Results: As of January 31, 2021, 10 patients were enrolled; 7 in Cohort 1 (H3B-6545 300 mg QD and palbociclib 100 mg QD) and 3 in Cohort 2 (H3B-6545 300 mg QD and palbociclib 125 mg QD). One patient in Cohort 1 was not evaluable for dose limiting toxicity (DLT) assessment and no DLT was observed in the 6 evaluable patients. One patient discontinued study treatment because of progression and no patients discontinued study treatment due to adverse events (AE). Grade 3 or 4 neutropenia and thrombocytopenia were observed in 4 patients and 1 patient, respectively. One patient had grade 3 hypercalcemia, generalized muscle weakness, hypophosphatemia, fall, and anemia and one patient had grade 3 lipase increase. Four patients had grade 1 bradycardia or sinus bradycardia (asymptomatic) 1 patient had grade 2 sinus bradycardia (symptomatic, no intervention required). Preliminary PK analysis suggested no clinically relevant drug-drug interactions between H3B-6545 and palbociclib, to be confirmed with data from additional cohorts. Recruitment is currently ongoing in Cohort 2. Updated results will be presented. Conclusions: H3B-6545, in combination with palbociclib, was well-tolerated. Clinical trial information: NCT04288089.

Abstract PD1-06: Trilaciclib improves overall survival when given with gemcitabine/carboplatin in patients with metastatic triple-negative breast cancer: Final analysis of a randomized phase 2 trial

Background

Trilaciclib is an intravenous (IV) cyclin-dependent kinase 4/6 (CDK4/6) inhibitor. Preliminary data showed that adding trilaciclib prior to gemcitabine plus carboplatin (GCb) significantly increased overall survival (OS) compared with GCb alone among patients with metastatic triple-negative breast cancer (mTNBC) (Tan et al., Lancet Oncol. 2019;20:1587-1601). Here, final antitumor efficacy results (objective response rate [ORR], progression-free survival [PFS], and OS) are reported for the whole study population, and in cohorts according to CDK4/6 dependence and level of programmed death ligand-1 (PD-L1) expression.

Methods

This was a randomized, open-label, phase 2 study of patients with mTNBC who had received ≤2 previous lines of chemotherapy in the recurrent/metastatic setting (NCT02978716). Patients were randomized (1:1:1) to receive GCb on days 1 and 8 (group 1, n=34), trilaciclib prior to GCb on days 1 and 8 (group 2, n=33), or trilaciclib alone on days 1 and 8 and prior to GCb on days 2 and 9 (group 3, n=35), in 21-day cycles. PFS and OS (prespecified secondary endpoints) were assessed in the intention-to-treat (ITT) population, and ORR in response-evaluable patients.

Patient tumors were characterized as CDK4/6 independent (basal-like) or indeterminate (HER2-enriched, normal-like, luminal A/B) according to the established PAM50 signature, or CDK4/6 dependent (luminal androgen receptor) or indeterminate (basal-like 1/2, mesenchymal) according to the established Lehmann signature. PD-L1 expression was scored as negative or positive if &lt;1% or ≥1% of the total tumor area contained PD-L1-labelled immune cells, respectively, using the Ventana SP142 assay. Association of CDK4/6 dependence and PD-L1 expression with antitumor efficacy was assessed using proportional hazards regression.

Results

Median follow-up was 8.4 months (range: 0.1-25.7) for group 1, 14.0 months (1.3-33.6) for group 2, and 15.3 months (3.5-33.7) for group 3. The ORR among response-evaluable patients was 7/24 (29.2%) in group 1, 15/30 (50.0%) in group 2, and 12/31 (38.7%) in group 3. Median PFS (95% confidence interval [CI]) in the ITT population was 5.7 (3.3, 9.9) months in group 1, 9.4 (6.1, 11.9) months in group 2, and 7.3 (6.2, 13.9) months in group 3, with hazard ratios (HRs) of 0.62 (P = 0.2099) and 0.63 (P = 0.1816), for groups 2 and 3 versus group 1, respectively. Overall, 73.5%, 39.4%, and 57.1% of patients in groups 1, 2, and 3 had died. Median OS (95% CI) was 12.6 (6.3, 15.6) months in group 1, not reached (NR) (10.2, NR) in group 2 (HR = 0.31, P = 0.0016), and 17.8 (12.9, 32.7) months in group 3 (HR = 0.40, P = 0.0004). For groups 2 and 3 combined, median OS was 19.8 (14.0, NR) months (HR = 0.37, P &lt;0.0001 vs group 1). ORR, PFS, and OS were comparable in tumors categorized as CDK4/6 dependent, independent, or indeterminate. Antitumor efficacy by PD-L1 status is provided in the Table.

Conclusions

Mature data from this study confirm that administering trilaciclib prior to GCb enhances antitumor efficacy compared with GCb alone, with statistically significant improvements in OS. Subgroup analyses suggest that adding trilaciclib prior to GCb benefits patients regardless of CDK4/6 dependence status and PD-L1 expression. Additional immune subtyping analyses are ongoing and will be presented.

Group 1Group 2Group 3PD-L1 +vePD-L1 –vePD-L1 +vePD-L1 –vePD-L1 +vePD-L1 –vePatients, n171016101616ORR, n (%)4 (23.5)3 (30.0)8 (50.0)4 (40.0)7 (43.8)4 (25.0)Median PFS, months (95% CI)3.5 (2.2, NR)9.5 (5.2, NR)7.9 (4.3, NR)11.9 (8.8, NR)9.0 (6.2, NR)6.9 (6.4, NR)P value (Wald Test)––0.3470.6040.0690.766HR (95% CI)––0.70 (0.3, 1.5)0.76 (0.3, 2.2)0.46 (0.2, 1.1)1.16 (0.4, 3.1)Median OS, months (95% CI)10.5 (6.3, 18.8)13.9 (12.6, NR)20.1 (10.2, NR)NR (9.4, NR)32.7 (15.3, NR)17.8 (12.9, NR)P value (Wald Test)––0.0280.0830.020.239HR (95% CI)––0.35 (0.1, 0.9)0.34 (0.1, 1.2)0.33 (0.1, 0.8)0.57 (0.2, 1.5)HR and P values are for comparisons between group 2 versus group 1, and group 3 versus group 1.+ve, positive; –ve, negative; CI, confidence interval; HR, hazard ratio; NR, not reached; ORR, objective response rate; OS, overall survival; PD-L1, programmed death ligand-1; PFS, progression-free survival.

Citation Format: Joyce O'Shaughnessy, Gail S Wright, Anu R Thummala, Michael A Danso, Lazar Popovic, Timothy J Pluard, Hyo S Han, Željko Vojnović, Nikola Vasev, Ling Ma, Donald A Richards, Sharon T Wilks, Dušan Milenković, Jie Xiao, Jessica A Sorrentino, Janet Horton, Antoinette R Tan. Trilaciclib improves overall survival when given with gemcitabine/carboplatin in patients with metastatic triple-negative breast cancer: Final analysis of a randomized phase 2 trial [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 PD1-06.

Abstract PS12-13: Balixafortide (a CXCR4 antagonist) plus eribulin in HER2 negative metastatic breast cancer: Final analysis from the Phase 1 single arm trial

Background: Balixafortide (B) is a potent, selective antagonist of the chemokine receptor CXCR4. High CXCR4 levels correlate with aggressive metastatic phenotypes and poor prognosis in metastatic breast cancer (MBC). Efficacy and safety data were published recently from the Phase 1 trial investigating B + eribulin (E) in patients with HER2 negative MBC1. We report the final safety and efficacy analyses from this trial, including an assessment of dose-response and adverse events of particular interest (AEPIs) (e.g. neutropenia, peripheral neuropathy).

Methods: In this single-arm, dose escalation trial, patients (pts) received E + increasing doses of B using a 3+3 design in 3 parts: Part I cohorts received low B doses (0.5−1mg/kg) + increasing E doses (1.1−1.4mg/m2); Part II dose-escalation cohort for B (1−5.5mg/kg) + 1.4mg/m2 E; Expanded Cohort (EC) to confirm safety and efficacy of B 5.5mg/kg + 1.4mg/m2 E. Most cohorts received E on days 2 and 9, and B on days 1−3 and 8−10 of 21-day cycles.

Results: At entry, all 56 women (age range 33−82 years) were HER2 negative, CXCR4 positive. Most pts were Caucasian and heavily pretreated in the metastatic setting (line of chemotherapy on study: 29% 2nd line, 50% 3rd line, 21% 4th line). 75% were hormone receptor positive and 23% had triple negative breast cancer.

A linear dose-exposure was observed over the entire dose range tested for B. Cmax and AUC for E were within published ranges.

Safety findings (including AEPIs) remained similar to those reported previously1.

No dose-limiting toxicities were confirmed; therefore, the maximum tolerated dose of B was not reached. The highest B dose evaluated was 5.5mg/kg; pharmacokinetic evaluation showed that further protocolled dose increments of B would not have provided a sufficient increase in plasma levels. In addition, the objective response rate in Part II was 3-fold greater than published for eribulin alone which suggested that the anti-tumor activity of B was worthy of further exploration at 5.5mg/kg in the EC.

Efficacy data for the trial are shown in the table.

These data suggest a potential dose-response relationship for B across all efficacy endpoints, with efficacy being numerically greatest in the EC. While PFS and OS should be interpreted with caution in single arm trials, these data suggest potential benefit for this combination. Further analyses will be presented.

Responses were observed regardless of line of chemotherapy on study or extent of CXCR4 expression and were numerically higher in hormone receptor positive patients.

Conclusions: A consistent dose response effect for B + E was suggested across all efficacy endpoints for heavily pretreated pts with HER2 negative MBC. When these results are compared with published data for E monotherapy in similar populations, the EC consistently shows numerically greater benefit for all efficacy endpoints2, 3.

The safety and tolerability of B + E appear comparable to published data on E or B alone, particularly for neutropenia and peripheral neuropathy1.

These results suggest that B + E could potentially provide a new treatment option in heavily pretreated patients with HER2 negative MBC. A Phase 3 trial exploring efficacy and safety of B 5.5mg/kg + E is ongoing.

1. Pernas S et al. Lancet Oncol. 2018; 19: 812−242. Cortes J et al. Lancet. 2011; 377: 914−9233. Kaufman PA et al. J Clin Oncol. 2015; 33: 594−601

Part II(N=21)Expanded Cohort(N=24)Overall Efficacy Population(N=54)Objective Response Rate (95% CI)33% (15−57)38% (19−59)30% (18−44)median duration in months (IQR)2.8 (1.4−3.3)4.4 (3.1−5.3)3.2 (2.2−4.5)Clinical Benefit Rate (95% CI)43% (22−66)63% (41−81)44% (31−59)median duration in months (IQR)5.4 (4.2−6.7)8.1 (6.3−10.8)6.9 (5.4−10.3)median PFS in months (95% CI)4.2 (3−5.4)6.2 (2.9−8.1)4.6 (3.2–5.7)median OS in months (95% CI)10.4 (7.7−18.4)18 (12.2–27.2)16.8 (10.6–18.4)Landmark OS estimate12 months (95% CI)40% (19−60)75% (53−88)60% (45−72)18 months (95% CI)30% (12−50)50% (29−68)42% (29−55)24 months (95% CI)20% (6−39)33% (16−52)25% (14−37)CI: confidence interval; IQR: interquartile range; OS: overall survival; PFS: progression free survival

Citation Format: Peter A. Kaufman, Sonia Pernas, Miguel Martin, Marta Gil-Martin, Patricia Gomez Pardo, Sara Lopez-Tarruella, Luis Manso, Eva Ciruelos, Jose Alejandro Perez-Fidalgo, Cristina Hernando, Foluso O Ademuyiwa, Katherine Weilbaecher, Ingrid A Mayer, Timothy J. Pluard, Maria Martinez Garcia, Francois Ringeisen, Daniela Schmitter, Javier Cortes. Balixafortide (a CXCR4 antagonist) plus eribulin in HER2 negative metastatic breast cancer: Final analysis from the Phase 1 single arm trial [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 PS12-13.

Abstract PS13-16: Pharmacokinetic evaluation of an oral paclitaxel DHP107 (Liporaxel®) in patients with recurrent or metastatic breast cancer (MBC): Phase II study (OPERA, NCT03326102)

Background: Paclitaxel is a microtubule stabilizing anticancer therapy used to treat multiple cancers including breast cancer. DHP107 is an oral paclitaxel solubilized in lipid components using DaeHwa-Lipid bAsed Self-Emulsifying Drug delivery system (DH-LASED) technology. It demonstrated comparable efficacy and safety to IV paclitaxel in a phase 3 study for patients with advanced gastric cancer (Ann Oncol 2018) leading to regulatory approval in Korea, and also met the primary endpoint (ORR 54.5%) as first-line therapy (ESMO 2019) in the OPTIMAL Phase II study in patients with HER2 negative metastatic breast cancer (MBC). The confirmatory OPTIMAL Phase III study is ongoing in Asia and Europe. The OPERA Phase II study was designed as multinational, multicenter, randomized, open-label study to establish pharmacokinetic (PK) profile and efficacy of DHP107 in patients with MBC in the U.S. Method: A total of 72 patients with metastatic HER2 negative (HR+/HER2- or triple-negative breast cancer (TNBC)) will be randomized in a 2:1 fashion to receive DHP107 (200mg/m2 orally twice a day on Days 1, 8, and 15 in a 28-day cycle) or IV paclitaxel (80 mg/m2 on Days 1, 8, and 15 in a 28-day cycle) until disease progression or unacceptable toxicity. Tumor assessments are performed every 8 weeks. PK analyses were performed in a subset of patients receiving DHP107. A total of 103 blood samples were collected on Day 1 of Cycle 1 at predose and 1, 2, 3, 4, 6, and 10 hours post dose (before the 2nd dose administration on Day 1), and at predose on Day 8 of Cycle 1. All PK parameters were calculated by non-compartmental analysis using Phoenix WinNonlin version® 8.1. Results: A total of 13 subjects were enrolled in the PK substudy, All 13 patients were female and of Caucasian, non-Hispanic, ethnicity. Median Tmax was 2.17 h (range 1.92-4.08). Mean Cmax and AUC0-10h and their coefficient of variations (CV) were 330 ng/mL (31.1%) and 1233 ng·h/mL (30.3%), respectively (Table 1). The PK parameters of DHP107 were similar to those in a previous Phase I study in Korean cancer patients where Cmax and AUC0-48h were 235 ng/mL (43.9%) and 1348 ng·h/mL (19.7%) (Invest New Drugs 2012).

Conclusion: PK profiles were well characterized from plasma concentrations in 13 Caucasian patients with MBC up to 10 hours after oral 200mg/m2 BID administration. DHP107 was rapidly absorbed and eliminated and inter-individual variability in exposure such as Cmax and AUClast was considered low. Compared to previous phase I PK results in Korean patients, Cmax and AUC parameters were similar after dosing with DHP107, demonstrating no clinically significant differences between Asian and Caucasian patients. Safety and efficacy will be evaluated in the ongoing OPERA and OPTIMAL studies.

Table 1StatisticTmax(h)Cmax(ng/mL)AUClast, 0-10h(ngh/mL)AUCinf(ngh/mL)N13131311Mean(SD)330(103)1233(374)1462(411)CV%31.130.328.1Median[Min-Max]2.17[1.92-4.08]

Citation Format: Hope S Rugo, Timothy J Pluard, Priyanka Sharma, Michelle Melisko, Ghassan Al-Jazayrly, Neelima Vidula, Yan Ji, David Weng, Hyeong-Seok Lim, Koung Eun Yoon, Hyun Ju Cho. Pharmacokinetic evaluation of an oral paclitaxel DHP107 (Liporaxel®) in patients with recurrent or metastatic breast cancer (MBC): Phase II study (OPERA, NCT03326102) [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 PS13-16.

Balixafortide (a CXCR4 antagonist) plus eribulin in HER2 negative metastatic breast cancer: Dose-response analysis of efficacy from phase I single-arm trial

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Background: Balixafortide (B) is a potent, selective antagonist of the chemokine receptor CXCR4. High CXCR4 levels correlate with aggressive metastatic phenotypes and poor prognosis in metastatic breast cancer (MBC). Efficacy and safety data were published recently from the Phase 1 trial investigating B + eribulin (E) in patients with HER2 negative MBC1. We report the final efficacy analyses from this trial, including assessment of dose-response. Methods: In this single-arm, dose escalation trial, patients (pts) received E + increasing doses of B using a 3+3 design in 3 parts: Part I (cohorts received low E doses); Part II (dose-escalation cohort for B [1−5.5mg/kg] + 1.4mg/m2 E); Expanded Cohort (EC; 5.5mg/kg B + 1.4mg/m2 E) to confirm safety and efficacy. Results: At entry, all 56 women (age range 33−82 years) were HER2-negative (IHC and/or FISH), CXCR4 positive. The majority were Caucasian. Most pts were heavily pre-treated in the metastatic setting (line of chemotherapy on study: 29% 2nd line, 50% 3rd line, 21% 4th line). 75% were hormone receptor positive and 23% had triple negative breast cancer. Conclusions: A consistent dose response effect for B + E was suggested in heavily pretreated pts with HER2 negative MBC across all efficacy endpoints. A comparison of these efficacy results, and particularly response data, with single agent data for E in similar populations2, 3 showed that pts in the EC had a more profound benefit observed consistently throughout all efficacy endpoints. Further data and analysis will be forthcoming for presentation. 1. 3 patients from Part II also included in EC because they received the B dose selected for EC (5.5mg/kg). 2. Part I was an initial safety run-in with lower E doses, and so is not included in the table. 1. Pernas S et al. Lancet Oncol. 2018; 19: 812−24 2. Cortes J et al. Lancet. 2011; 377: 914−923 3. Kaufman PA et al. J Clin Oncol. 2015; 33: 594−601. Clinical trial information: NCT01837095 . [Table: see text]

Management of adverse events in patients with HER2+ metastatic breast cancer treated with tucatinib, trastuzumab, and capecitabine (HER2CLIMB)

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Background: Tucatinib (TUC) is an investigational TKI, highly selective for HER2 without significant inhibition of EGFR. HER2CLIMB is a randomized trial of TUC vs placebo in combination with trastuzumab and capecitabine in patients (pts) with HER2+ breast cancer (NCT02614794, Murthy NEJM 2019). The most common G ≥3 adverse events (AEs) with higher incidence on the TUC arm (diarrhea, palmar-plantar erythrodysesthesia syndrome [PPE], and elevated liver enzymes) are described herein. Methods: Given that pts on the TUC arm had a longer duration of tx than those on the control arm, time-at-risk exposure-adjusted incidence rates of diarrhea, AST, ALT, and PPE were calculated as the number of pts with an event divided by the total exposure time-at-risk of an initial occurrence of the event among pts in the tx group. Time-to-event analyses were conducted for AST/ALT/bilirubin (in aggregate), diarrhea, and PPE. Results: Diarrhea and elevated AST/ALT/bilirubin on both the TUC and control arms were primarily G1/2 and manageable with dose modifications, and in some cases of diarrhea, with antidiarrheal tx. Median time to diarrhea onset was shorter on the TUC arm compared to control. For AST/ALT/bilirubin and PPE, median time to first onset was Cycles 1 and 2. On the TUC arm, antidiarrheals were used in 49.7% of cycles in which diarrhea was reported (39.8% on the control arm), and when used, the median duration of use on each arm was 3 days per cycle. Prophylactic antidiarrheals were not required per protocol. When adjusted for exposure (time-at-risk exposure-adjusted incidence rate per 100 person-years), the difference in G ≥3 events between tx arms becomes similar for diarrhea and PPE (21 vs 17 and 21 vs 19). The difference in G ≥3 events between arms is reduced for AST and ALT (7 vs 1 and 8 vs 1). Conclusions: TUC with trastuzumab and capecitabine was well-tolerated. Rates of G ≥3 diarrhea and PPE were similar between tx arms. Elevated liver enzymes were higher on the TUC arm, but were transient and reversible. Discontinuation of TUC due to AEs was rare. Clinical trial information: NCT02614794 . [Table: see text]

Abstract P6-11-18: Medical, financial and insurance related concerns of metastatic breast cancer patients

Background: The medical, financial and insurance concerns of patients throughout the cancer trajectory are well documented. Over a quarter of patients report at least one financial problem. Due to the financial burden of cancer care, patients report that they delay filling prescriptions, have difficulty making ends meet, are concerned about their household’s financial situation and skip doses of medication. These are significant findings as consistent use of medication is necessary for treatment and those with increased financial problems also have lower scores on physical and mental health quality of life measures. While most providers agree that the burden of metastatic breast cancer (MBC) is also significant, little information is known about the specific medical, financial and insurance needs of those with MBC. Methods: Saint Luke’s Cancer Institute (SLCI) employs providers in the fields of medical and surgical oncology, gynecologic oncology, hematology and radiation oncology who subspecialize in every type of cancer. In October of 2016, the Koontz Center for Advanced Breast Cancer was established within the Saint Luke’s Cancer Institute. This center focuses exclusively on patients with MBC with a dual focus of improving outcomes and quality of life of those with MBC. In addition to a robust therapeutic research program, genomics, and immunotherapy, a comprehensive supportive/integrative team, including social worker, is imbedded in the center. Social workers see patients throughout the entirety of SLCI and the Koontz Center for Advanced Breast Cancer. As part of their patient interactions, social workers document the date of intervention, patients’ name, concern addressed, and length of every interaction. The following data compares the reported needs of those with MBC in the Koontz Center for Advanced Breast Cancer to the non-MBC patients within the SLCI population from September 1st of 2017 to August 31st of 2018. Results: In total, there were 2,072 interactions with non-MBC patients during this period. The top three reported concerns were medication assistance (n=335, 16.15%), being uninsured (n=298, 14.37%) and transportation (n=284, 13.69%). For those with MBC, there were a total of 476 interactions within the same time frame and the top three reported concerns were medication assistance (n=166, 34.87%), insurance issues (n=75, 15.76%) and financial distress (n=66, 13.87%). About 55% of non-MBC patients (n=334, 55.95%) have repeat appointments and meet with social work on average 5 times. Of MBC patients, 60.67% (n=54) have repeat appointments and meet with social work on average 7 times. For one time encounters with social work, those with non-MBC patients lasted 21 minutes and 9 seconds and encounters with MBC patients lasted 24 minutes and 34 seconds. Conclusion: Results indicate differences and similarities for MBC patients compared to non-MBC patients. This could be explained by the fact that both populations share several concerns such as financial barriers to medications, high insurance premiums and decreased ability to work. However, due to the nature of MBC, patients with MBC often deal with these concerns for longer periods of time and are often required to utilize expensive specialty medication. The top three concerns of MBC patients including medication assistance, insurance issues, and financial distress, are closely related to one another as it relates to gaps in healthcare coverage. The high cost of treatment for advanced disease, coupled with the specific and unique needs of those living with MBC, can directly impact patients’ ability to access necessary care. These potential causes, as well as how the Koontz Center for Advanced Breast Cancer works to mitigate these issues, will be addressed in further detail.

Citation Format: Savannah Joy Geske, Katie Ambrosier, Timothy J. Pluard. Medical, financial and insurance related concerns of metastatic breast cancer patients [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 P6-11-18.

Abstract OT1-05-02: A phase II study to evaluate the efficacy, safety and pharmacokinetics of DHP107 (Liporaxel®, oral paclitaxel) compared to IV paclitaxel in patients with recurrent or metastatic breast cancer: OPERA (NCT03326102)

Background: Paclitaxel is a commonly used anticancer drug worldwide for various cancers including breast cancer. DHP107 is a novel oral formulation of lipid based components and paclitaxel. DHP107 showed comparable efficacy and safety to IV paclitaxel in a phase 3 study for patients with advanced gastric cancer (DREAM study, Ann Oncol 2018). DHP107, Liporaxel® was approved as the first oral paclitaxel in 2016 for gastric cancer in Korea. Currently the OPTIMAL Phase III study is ongoing in Korea and China to evaluate the efficacy of Liporaxel® as first-line therapy in recurrent or metastatic breast cancer. The OPERA Phase II study aims to evaluate the efficacy, safety and pharmacokinetics of DHP107 compared to IV Paclitaxel in non-Asian American patients in U.S. with recurrent or metastatic breast cancer. Trial Design: The OPERA study is a multi-center, randomized, open-label phase II trial enrolling HER2 negative (HR+/HER2- or triple-negative breast cancer (TNBC)) recurrent or metastatic breast cancer patients. Seventy two eligible subjects are being randomized in a 2:1 fashion to receive DHP107(200mg/m2 orally twice daily) or IV paclitaxel 80 mg/m2 on Days 1, 8, and 15 in a 28-day cycle) until disease progression, intolerable toxicity, or withdrawal from this study. Stratification factors include ‘TNBC vs. non-TNBC’ and ‘disease-free interval (DFI) ≤ 12 months vs. DFI &gt; 12 months’. A subset of the first 12 eligible subjects receiving DHP107, blood samples for PK analysis are collected on Day 1 of Cycle 1 at predose(0) and 1, 2, 3, 4, 6, and 10 hours post dose (before the 2nd dose administration on Day 1), and on Day 8 of Cycle 1 at predose (before the 1st dose on Day 8). Tumor assessments are performed every 8 weeks ± 7 days from C1D1 until disease progression or initiation of subsequent chemotherapy. Eligibility Criteria: Subjects must have confirmed HER2 negative breast cancer by immunohistochemistry (IHC) or in situ hybridization (ISH). HR positive (&gt;1%) or negative patients are eligible. Subjects can have received up to 3 lines of therapy for advanced disease, without prior exposure to taxane in the advanced stage setting. Subjects must have performance status of ≤2 on the Eastern Cooperative Oncology Group (ECOG) scale and measurable disease according to the Response Evaluation Criteria in Solid Tumors Version 1.1 (by RECIST version 1.1). Subjects with treated CNS metastases that are documented to be stable by CT or MRI imaging ≥4 weeks after completion of radiation and who do not require systemic corticosteroids are eligible. Subjects with neuropathy grade ≥2 based on CTCAE v4.03 are excluded. Specific Aims: The primary endpoint is objective response rate (ORR). Secondary endpoints include progression free survival (PFS), overall survival (OS), time-to-treatment failure (TTF), duration of response (DOR), disease control rate (DCR), quality-of-life (QoL) and safety. Statistical Design: Seventy two subjects are being enrolled, with an estimated drop-out rate of 10%. This sample size is sufficient to ensure that the lower one-sided 95% confidence limit for the true difference in response rates extends no more than 20% from the observed difference; this calculation assumes that the observed ORR is 60% in both groups. Target Accrual: The first subject was enrolled in July 2018 and recruitment is ongoing. Enrollment of 72 evaluable subjects is expected to complete in Q2 2020.

Citation Format: Timothy J Pluard, Priyanka Sharma, Michelle E. Melisko, Neelima Vidula, David E Weng, Jane D Skelton, Koung Eun Yoon, Hyun Ju Cho, Hope S Rugo. A phase II study to evaluate the efficacy, safety and pharmacokinetics of DHP107 (Liporaxel®, oral paclitaxel) compared to IV paclitaxel in patients with recurrent or metastatic breast cancer: OPERA (NCT03326102) [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 OT1-05-02.

Trilaciclib plus chemotherapy versus chemotherapy alone in patients with metastatic triple-negative breast cancer: a multicentre, randomised, open-label, phase 2 trial

BACKGROUND

Trilaciclib is an intravenous cell-cycle inhibitor that transiently maintains immune cells and haemopoietic stem and progenitor cells in G1 arrest. By protecting the immune cells and bone marrow from chemotherapy-induced damage, trilaciclib has the potential to optimise antitumour activity while minimising myelotoxicity. We report safety and activity data for trilaciclib plus gemcitabine and carboplatin chemotherapy in patients with metastatic triple-negative breast cancer.

METHODS

In this randomised, open-label, multicentre, phase 2 study, adult patients (aged ≥18 years) with evaluable, biopsy-confirmed, locally recurrent or metastatic triple-negative breast cancer who had no more than two previous lines of chemotherapy were recruited from 26 sites in the USA, three in Serbia, two in North Macedonia, one in Croatia, and one in Bulgaria; sites were academic and community hospitals. Availability of diagnostic samples of tumour tissue confirming triple-negative breast cancer was a prerequisite for enrolment. Eligible patients were randomly assigned (1:1:1) by an interactive web-response system, stratified by number of previous lines of systemic therapy and the presence of liver metastases, to receive intravenous gemcitabine 1000 mg/m² and intravenous carboplatin (area under the concentration-time curve 2 μg × h/mL) on days 1 and 8 (group 1), gemcitabine and carboplatin plus intravenous trilaciclib 240 mg/m² on days 1 and 8 (group 2), or gemcitabine and carboplatin on days 2 and 9 plus trilaciclib on days 1, 2, 8, and 9 (group 3) of 21-day cycles. Patients continued treatment until disease progression, unacceptable toxicity, withdrawal of consent, or discontinuation by the investigator. The primary objective was to assess the safety and tolerability of combining trilaciclib with gemcitabine and carboplatin chemotherapy. The primary endpoints were duration of severe neutropenia during cycle 1 and the occurrence of severe neutropenia during the treatment period. Overall survival was included as a key secondary endpoint. Analyses were in the intention-to-treat population. Safety was assessed in all patients who received at least one dose of study treatment. This study is registered with EudraCT, 2016-004466-26, and ClinicalTrials.gov, NCT02978716, and is ongoing but closed to accrual.

FINDINGS

Between Feb 7, 2017, and May 15, 2018, 142 patients were assessed for eligibility and 102 were randomly assigned to group 1 (n=34), group 2 (n=33), or group 3 (n=35). Of all patients, 38 (37%) had received one or two lines of previous chemotherapy in the metastatic setting. Median follow-up was 8·4 months (IQR 3·8-13·6) for group 1, 12·7 months (5·5-17·4) for group 2, and 12·9 months (6·7-16·8) for group 3. Data cutoff for myelosuppression endpoints was July 30, 2018, and for antitumour activity endpoints was May 17, 2019. During cycle 1, mean duration of severe neutropenia was 0·8 day (SD 2·4) in group 1, 1·5 days (3·5) in group 2, and 1·0 day (2·6) in group 3 (group 3 vs group 1 one-sided adjusted p=0·70). Severe neutropenia occurred in nine (26%) of 34 patients in group 1, 12 (36%) of 33 patients in group 2, and eight (23%) of 35 patients in group 3 (p=0·70). Overall survival was 12·6 months (IQR 5·8-15·6) in group 1, 20·1 months (9·4-not reached) in group 2, and 17·8 months (8·8-not reached) in group 3 (group 3 vs group 1 two-sided p=0·0023). The most common treatment-emergent adverse events were anaemia (22 [73%] of 34), neutropenia (21 [70%]), and thrombocytopenia (18 [60%]) in group 1; neutropenia (27 [82%] of 33), thrombocytopenia (18 [55%]) and anaemia (17 [52%]) in group 2; and neutropenia (23 [66%] of 35), thrombocytopenia (22 [63%]), and nausea (17 [49%]) in group 3. There were no treatment-related deaths.

INTERPRETATION

No significant differences were observed in myelosuppression endpoints with trilaciclib plus gemcitabine and carboplatin in patients with metastatic triple-negative breast cancer; however, the regimen was generally well tolerated and overall survival results were encouraging. Further studies of trilaciclib in this setting are warranted.

FUNDING

G1 Therapeutics.

Matched Whole-Genome Sequencing (WGS) and Whole-Exome Sequencing (WES) of Tumor Tissue with Circulating Tumor DNA (ctDNA) Analysis: Complementary Modalities in Clinical Practice

Tumor heterogeneity, especially intratumoral heterogeneity, is a primary reason for treatment failure. A single biopsy may not reflect the complete genomic architecture of the tumor needed to make therapeutic decisions. Circulating tumor DNA (ctDNA) is believed to overcome these limitations. We analyzed concordance between ctDNA and whole-exome sequencing/whole-genome sequencing (WES/WGS) of tumor samples from patients with breast (n = 12), gastrointestinal (n = 20), lung (n = 19), and other tumor types (n = 13). Correlation in the driver, hotspot, and actionable alterations was studied. Three cases in which more-in-depth genomic analysis was required have been presented. A total 58% (37/64) of patients had at least one concordant mutation. Patients who had received systemic therapy before tissue next-generation sequencing (NGS) and ctDNA analysis showed high concordance (78% (21/27) vs. 43% (12/28) p = 0.01, respectively). Obtaining both NGS and ctDNA increased actionable alterations from 28% (18/64) to 52% (33/64) in our patients. Twenty-one patients had mutually exclusive actionable alterations seen only in either tissue NGS or ctDNA samples. Somatic hotspot mutation analysis showed significant discordance between tissue NGS and ctDNA analysis, denoting significant tumor heterogeneity in these malignancies. Increased tissue tumor mutation burden (TMB) positively correlated with the number of ctDNA mutations in patients who had received systemic therapy, but not in treatment-naïve patients. Prior systemic therapy and TMB may affect concordance and should be taken into consideration in future studies. Incorporating driver, actionable, and hotspot analysis may help to further refine the correlation between these two platforms. Tissue NGS and ctDNA are complimentary, and if done in conjunction, may increase the detection rate of actionable alterations and potentially therapeutic targets.

SGNLVA-002: Single-arm, open label phase Ib/II study of ladiratuzumab vedotin (LV) in combination with pembrolizumab for first-line treatment of patients with unresectable locally advanced or metastatic triple-negative breast cancer

TPS1110

Background: There are currently no curative treatments for patients with metastatic triple-negative breast cancer (mTNBC), and prognosis for this disease is very poor. Emerging treatment combinations of anti-programmed death ligand 1 (PD-L1) agents with chemotherapy have shown promise in mTNBC. SGN-LIV1A, or ladiratuzumab vedotin (LV), is a novel investigational humanized IgG1 antibody-drug conjugate (ADC) directed against LIV-1, which is highly expressed in breast cancer cells. LV mediates delivery of monomethyl auristatin E (MMAE), which drives antitumor activity through cytotoxic cell killing and induces immunogenic cell death (ICD). Preliminary results from an ongoing phase 1 study of LV monotherapy has shown LV to be well tolerated and to have encouraging antitumor activity in patients with mTNBC. Combining LV and pembrolizumab may result in complementary, as well as synergistic, activity through LV-induced ICD that creates a microenvironment favorable for enhanced anti-PD-L1 activity. Methods: This single-arm, open-label, phase 1b/2 study evaluates the safety and antitumor activity of LV in combination with pembrolizumab as first-line therapy for patients with unresectable locally advanced or mTNBC (NCT03310957, 2017-002289-35). Patients must have measureable disease per RECIST v1.1, an ECOG score of 0 or 1, and no prior cytotoxic or anti-PD-L1 treatment for advanced disease. This study has 2 parts that are enrolling sequentially: a dose-finding phase that starts at LV 2.5 mg/kg + pembrolizumab 200 mg intravenously every three weeks, and a dose expansion phase. The primary objectives are to evaluate the safety/tolerability and objective response rate of LV + pembrolizumab, and identify the recommended phase 2 dose of LV. The secondary objectives are to assess duration of response, disease control rate, progression-free survival, and overall survival. Additional objectives include assessing PD-L1 and LIV-1 expression-response relationship. Study enrollment is ongoing in the US and EU. Clinical trial information: NCT03310957.

Balixafortide (a CXCR4 antagonist) + eribulin in HER2-negative metastatic breast cancer (MBC): Survival outcomes of the phase I trial

2606

Background: Balixafortide (B) is a potent antagonist of the chemokine receptor CXCR4. Preclinical evidence suggests that disrupting CXCR4 dependent pathways prevents development of breast cancer metastases, enhances the cytotoxic effect of chemotherapy and immunotherapy, and counteracts tumor cell evasion of the immune system. Encouraging safety and efficacy data were published recently from the ongoing Phase 1 trial investigating B + eribulin (E) in patients with HER2 negative MBC (Pernas S. et al. Lancet Oncol. 2018; 19: 812−24). The objective response rate, median progression free survival and median overall survival (OS) for the expanded cohort (EC) and the overall efficacy population (OEP) were 37.5% and 29.6%, 6.2 months and 4.5 months, and 18 months and 16.8 months, respectively. Here we report the 18 and 24 months landmark OS data from this trial. Methods: This trial enrolled 56 patients with HER2-negative, CXCR4-positive MBC, previously treated with 1−3 chemotherapy regimens for MBC. A 3+3 dose escalation design was used, followed by an EC. All cohorts received E on days 2 and 9, and B on days 1−3 and 8−10 of 21 day cycles. The association between various baseline biomarkers and treatment outcomes including OS is currently being investigated in a multivariate analysis (MVA). Results: Landmark survival data for the trial are shown in the table. Clinical trial information: NCT01837095. Conclusions: Landmark 18 months and 24 months OS data are consistent with the positive trend of all efficacy read-outs observed in this study and safety information is consistent with what was previously reported. Although inter-trial comparisons should be interpreted with caution, these survival rates, especially for the EC, are higher than those reported for eribulin monotherapy in similar MBC populations. These promising results suggest that B + E could potentially provide a new treatment option in heavily pre-treated patients with HER2 negative MBC and this is currently being investigated in a pivotal, randomized trial.[Table: see text]

Abstract PD1-01: Trilaciclib (T), a CDK4/6 inhibitor, dosed with gemcitabine (G), carboplatin (C) in metastatic triple negative breast cancer (mTNBC) patients: Preliminary phase 2 results

Background: Cytotoxic chemotherapy-induced damage of hematopoietic stem and progenitor cells (HSPCs) results in acute toxicities consisting of multi-lineage myelosuppression, and late onset toxicities consisting of progressive bone marrow suppression with increased incidence of therapy-related myeloid neoplasms. T is an IV CDK4/6 inhibitor in development to preserve HSPC and immune system function during cytotoxic chemotherapy (myelopreservation). Proof of concept for myelopreservation with T was observed in a randomized, placebo-controlled Phase 2 trial in small-cell lung cancer patients receiving 1st-line chemotherapy. This trial in mTNBC patients (NCT02978716) was designed to explore the utility of T in combination with GC.

Methods: This Phase 2, randomized, open-label study enrolled patients in the US and EU with mTNBC who had received 0-2 prior systemic cytotoxic therapies in the locally recurrent or metastatic setting and had no symptomatic brain metastases. Patients were randomized (1:1:1) to GC alone (Group 1) or T plus GC (Group 2) using a standard schedule (D1, 8 every 21 days) or to an alternative schedule (T on D1, 2, 8 and 9 with GC on D2 and 9 every 21 days; Group 3). On those days when both T and GC were scheduled, T was administered iv prior to GC infusion. Prophylactic growth factors were not administered in cycle 1; otherwise supportive care was allowed as needed. Primary objectives were safety and tolerability; tumor response was evaluated using RECIST v1.1 and PFS and OS were assessed. Myelopreservation endpoints reflecting the potential effects of T on multiple cellular lineages include occurrence of Grade 4 neutropenia (primary), RBC and platelet transfusions (primary), and lymphocyte counts with immune profiling (secondary and exploratory). A signature of CDK4/6 independence developed from preclinical data will be used to evaluate archival tumor tissue samples and data analysis is ongoing.

Results: 95 patients were dosed; median age 57 years (range 32,86), ECOG PS 0 (53%) or 1 (47%), 25% had liver metastases at baseline, and approximately 50% had received no systemic therapy in the recurrent/metastatic setting. Fifty-five patients remain on treatment. Disease progression was the most common reason for drug discontinuation (22/40; 55%). Overall the most common (≥ 25%) TEAEs were anemia (47%), nausea (35%), fatigue (34%), neutropenia (32%), platelet count decreased (25%), and vomiting (25%). The most frequent (≥ 15%) Grade 3 or 4 TEAEs were hematologic toxicities, i.e. neutropenia (28%), anemia (21%), neutrophil count decreased (21%) and thrombocytopenia (16%). These were also the most frequent drug-related TEAEs observed. Tumor efficacy data are being evaluated.

Conclusions: This trial, assessing the myelopreservation effects of T when combined with GC in patients with mTNBC, has completed enrollment. Myelopreservation data, immune profiling, as well as ORR and preliminary PFS results will be presented by study arm at the meeting.

Citation Format: O'Shaughnessy J, Wright GS, Thummala AR, Danso MA, Popovic L, Pluard TJ, Cheung E, Han HS, Daniel BR, Vojnovic Z, Vasev N, Ling M, Richards DA, Wilks ST, Milenkovic D, Sorrentino JA, Roberts PJ, Bomar M, Yang Z, Antal JM, Malik RK, Morris SR, Tan A. Trilaciclib (T), a CDK4/6 inhibitor, dosed with gemcitabine (G), carboplatin (C) in metastatic triple negative breast cancer (mTNBC) patients: Preliminary phase 2 results [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr PD1-01.

Abstract P1-11-20: Patient reported supportive care needs in a dedicated advanced breast cancer center

Background: As of January 1st, 2017 nearly 154,794 women in the US will be living with metastatic breast cancer (MBC) and rates are expected to increase. Additionally, 58.3% of individuals with MBC, and their caregivers, believe that people with MBC have unique informational, emotional and physical needs that are unmet. However, there are still few research studies examining these needs.

Methods: In October of 2016, the Koontz Center for Advanced Breast Cancer was established in Kansas City, MO. Supportive services assume a large role in this center to assist in caring for the whole person and improving quality of life. During the initial consult, the patient meets with the medical oncologist, psychologist, social worker, nutritionist, exercise physiologist and chaplain. All patients complete forms assessing multiple domains that may influence the patient's treatment and outcomes. We use the PROMIS (Patient-Reported Outcome Measurement Information System) measures to assess sleep, physical function, fatigue and pain interference, the Daily Spiritual Experience Scale (DSES) to assess spiritual concerns, the DSM-5 Self-Rated Level 1 Cross-Cutting Symptom Measure-Adult to assess mental health concerns and Koontz Center forms to assess social work and nutritional concerns. The following data is from assessments collected through May of 2018.

Results: Eighty-two individuals were included in the analysis. The mean age was 60.1 (SD=10.6) and 98% (n=80) were female. A majority were white, non-Hispanic (88%; n=71). Sleep related impairment was mild for 27 (33.8%) individuals, moderate for 22 (27.5%) and severe for 3 (3.8%). For physical function, 12 (14.8%) individuals had mild, 32 (39.5%) moderate and 19 (23.5%) severe impairment. Twelve (15%) individuals had mild, 25 (31.3%) moderate and 6 (7.5%) severe symptoms of fatigue. For pain interference, 14 (17.3%) individuals had mild, 24 (29.6%) moderate and 9 (11.1%) severe symptoms. The average DSES score was 12.6 (SD=6.8) out of 36 with lower scores indicating stronger spiritual satisfaction. The top three mental health concerns were anxiety (n=47; 58.8%), depression (n=40; 50%) and somatic symptoms (n=38; 47.5%). Seventeen percent (n=14) reported concern over weight and 30% (n=24) reported losing weight over the past two weeks. The top three areas individuals reported needing assistance in were finding financial resources (n=16; 20.5%), help at home (n=11; 14.1%) and insurance questions (n=10; 12.8%). The top four areas individuals reported needing support in were information on support groups (n=20; 25.6%), managing stress (n=20; 25.6%), coping with cancer diagnosis (n=14; 17.9%) and communicating with children about cancer (n=14; 17.9%). Also, 38% (n=28) endorsed wanting information about an advanced directive. Changes across age and symptom complexes were also noted and will be presented.

Conclusion: The data indicate that there are a wide variety of physical, spiritual, nutritional, social and psychological concerns for those coping with a MBC diagnosis. Future treatment of those with MBC should integrate supportive services to address these symptoms.

Citation Format: Geske SJ, Pluard TJ, Amazu C, Holden R. Patient reported supportive care needs in a dedicated advanced breast cancer center [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P1-11-20.

Abstract P4-01-05: Cell free DNA analysis identifies actionable ERBB2 amplifications in patients with HER2 equivocal breast cancer

Background:

Determination of ERBB2 (HER2) expression or amplification informs eligibility of HER2-targeted therapies. ASCO and NCCN guidelines recommend evaluation of HER2 status on primary invasive breast cancers and on a metastatic site if stage IV, where possible, as treatment is based on the status of the metastasis. Reassessment of HER2 status should also be considered in patients with disease recurrence as initially HER2-negative tumors may acquire HER2 amplification at progression. HER2 status can be complicated by equivocal results from in situ hybridization (ISH) and/or immunohistochemistry (IHC). Clarification requires reflex testing on the same tissue specimen or repeat testing on a new specimen, however some patients' tissue status remains equivocal. Furthermore, metastases to bone, lung, or brain may be difficult to re-biopsy or of low DNA quality. Rapid and non-invasive blood-based cell-free DNA (cfDNA) NGS may facilitate identification of HER2 targetable disease in advanced breast cancer.

Methods:

We assessed the frequency of ERBB2 amplification detectable by a blood-based cell-free DNA (cfDNA) assay among patients with metastatic breast cancer with equivocal HER2 results in tissue. cfDNA samples were ordered as part of routine clinical care using an assay validated for the detection of copy number amplification in ERBB2 (tests run between 03/2014-04/2017 by Guardant Health, Redwood City, CA). Submitted pathology reports were reviewed for HER2 status which was categorized as positive, negative, or equivocal based on the interpretation issued by the reading pathologist at the time the test was ordered. Patients were included if they had an equivocal result on IHC and/or ISH unless both assays were performed on the same specimen and one provided a definitive negative or positive HER2 result. Additionally, 4 patients with equivocal IHC or ISH results were excluded as biopsy of another tumor site revealed a positive HER2 result around the same time as the equivocal test. For the 349 patients with multiple cfDNA samples, the earliest pathology report was referenced.

Results:

Tissue HER2 status was available for 1,853 unique patients (98.8% female, median age at testing was 58y, range 26-91y). 141 patients (7.6%) had equivocal HER2 results in tissue; 99 by IHC alone, 14 by ISH alone, and 28 were equivocal by both assays. Among these, 126 patients (89.4%) had at least one sample with ctDNA detected. 12/126 (9.5%) had amplification of ERBB2 detected in at least one cfDNA sample. Samples were drawn a median of 267 days after tissue collection (range 4 days – 11.5 years). Frequency of ERBB2 amplification was similar regardless of time between tissue and blood collection but was higher among patients with ISH results alone (4/14, 36.4%) compared to those with IHC alone (6/89, 6.7%) or both assays (6/26, 7.6%; p=0.006).

Conclusion:

cfDNA testing identifies a significant number of patients with HER2-targetable advanced breast cancer whose tissue was HER2 equivocal. cfDNA testing may supplement tissue-based methods to help clarify HER2 status in metastatic disease as well as identify patients who may acquire HER2 amplification subsequent to their initial biopsy.

Citation Format: Rich TA, Raymond VM, Ahn ER, Banks KC, Brufsky A, Lee C, Lippman M, Pluard TJ, Schwab RB, Lanman RB. Cell free DNA analysis identifies actionable ERBB2 amplifications in patients with HER2 equivocal breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P4-01-05.

Abstract PD1-02: Withdrawn

This abstract was withdrawn by the authors.

Citation Format: Cortes J, Martin M, Pernas S, Gomez Pardo P, Lopez-Tarruella S, Gil-Martin M, Manso L, Ciruelos E, Perez-Fidalgo JA, Hernando C, Ademuyiwa FO, Weilbaecher K, Mayer I, Pluard TJ, Martinez Garcia M, Vahdat L, Wach A, Barker D, Romagnoli B, Kaufman PA. Withdrawn [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr PD1-02.

First results on survival from a large Phase 3 clinical trial of an autologous dendritic cell vaccine in newly diagnosed glioblastoma

Background

Standard therapy for glioblastoma includes surgery, radiotherapy, and temozolomide. This Phase 3 trial evaluates the addition of an autologous tumor lysate-pulsed dendritic cell vaccine (DCVax^®-L) to standard therapy for newly diagnosed glioblastoma.

Methods

After surgery and chemoradiotherapy, patients were randomized (2:1) to receive temozolomide plus DCVax-L (n = 232) or temozolomide and placebo (n = 99). Following recurrence, all patients were allowed to receive DCVax-L, without unblinding. The primary endpoint was progression free survival (PFS); the secondary endpoint was overall survival (OS).

Results

For the intent-to-treat (ITT) population (n = 331), median OS (mOS) was 23.1 months from surgery. Because of the cross-over trial design, nearly 90% of the ITT population received DCVax-L. For patients with methylated MGMT (n = 131), mOS was 34.7 months from surgery, with a 3-year survival of 46.4%. As of this analysis, 223 patients are ≥ 30 months past their surgery date; 67 of these (30.0%) have lived ≥ 30 months and have a Kaplan-Meier (KM)-derived mOS of 46.5 months. 182 patients are ≥ 36 months past surgery; 44 of these (24.2%) have lived ≥ 36 months and have a KM-derived mOS of 88.2 months. A population of extended survivors (n = 100) with mOS of 40.5 months, not explained by known prognostic factors, will be analyzed further. Only 2.1% of ITT patients (n = 7) had a grade 3 or 4 adverse event that was deemed at least possibly related to the vaccine. Overall adverse events with DCVax were comparable to standard therapy alone.

Conclusions

Addition of DCVax-L to standard therapy is feasible and safe in glioblastoma patients, and may extend survival.

Trial registration Funded by Northwest Biotherapeutics; Clinicaltrials.gov number: NCT00045968; https://clinicaltrials.gov/ct2/show/NCT00045968?term=NCT00045968&rank=1; initially registered 19 September 2002

Correlation of Somatic Genomic Alterations Between Tissue Genomics and ctDNA Employing Next-Generation Sequencing: Analysis of Lung and Gastrointestinal Cancers

Next-generation Sequencing (NGS) of cancer tissues is increasingly being carried out to identify somatic genomic alterations that may guide physicians to make therapeutic decisions. However, a single tissue biopsy may not reflect complete genomic architecture due to the heterogeneous nature of tumors. Circulating tumor DNA (ctDNA) analysis is a robust noninvasive method to detect and monitor genomic alterations in blood in real time. We analyzed 28 matched tissue NGS and ctDNA from gastrointestinal and lung cancers for concordance of somatic genomic alterations, driver, and actionable alterations. Six patients (21%) had at least one concordant mutation between tissue and ctDNA sequencing. At the gene level, among all the mutations (n = 104) detected by tissue and blood sequencing, 7.7% (n = 8) of mutations were concordant. Tissue and ctDNA sequencing identified driver mutations in 60% and 64% of the tested samples, respectively. We found high discordance between tissue and ctDNA testing, especially with respect to the driver and actionable alterations. Both tissue and ctDNA NGS detected actionable alterations in 25% of patients. When somatic alterations identified by each test were combined, the total number of patients with actionable mutations increased to 32%. Our data show significant discordance between tissue NGS and ctDNA analysis. These results suggest tissue NGS and ctDNA NGS are complementary approaches rather than exclusive of each other. When performed in isolation, tissue and ctDNA NGS can each potentially miss driver and targetable alterations, suggesting that both approaches should be incorporated to enhance mutation detection rates. Larger prospective studies are needed to better clarify this emerging precision oncology landscape. Mol Cancer Ther; 17(5); 1123-32. ©2018 AACR.

Ral signaling pathway in health and cancer

The Ral (Ras‐Like) signaling pathway plays an important role in the biology of cells. A plethora of effects is regulated by this signaling pathway and its prooncogenic effectors. Our team has demonstrated the overactivation of the RalA signaling pathway in a number of human malignancies including cancers of the liver, ovary, lung, brain, and malignant peripheral nerve sheath tumors. Additionally, we have shown that the activation of RalA in cancer stem cells is higher in comparison with differentiated cancer cells. In this article, we review the role of Ral signaling in health and disease with a focus on the role of this multifunctional protein in the generation of therapies for cancer. An improved understanding of this pathway can lead to development of a novel class of anticancer therapies that functions on the basis of intervention with RalA or its downstream effectors.

Neratinib Efficacy and Circulating Tumor DNA Detection of HER2 Mutations in HER2 Nonamplified Metastatic Breast Cancer

Purpose: Based on promising preclinical data, we conducted a single-arm phase II trial to assess the clinical benefit rate (CBR) of neratinib, defined as complete/partial response (CR/PR) or stable disease (SD) ≥24 weeks, in HER2^mut nonamplified metastatic breast cancer (MBC). Secondary endpoints included progression-free survival (PFS), toxicity, and circulating tumor DNA (ctDNA) HER2^mut detection.Experimental Design: Tumor tissue positive for HER2^mut was required for eligibility. Neratinib was administered 240 mg daily with prophylactic loperamide. ctDNA sequencing was performed retrospectively for 54 patients (14 positive and 40 negative for tumor HER2^mut).Results: Nine of 381 tumors (2.4%) sequenced centrally harbored HER2^mut (lobular 7.8% vs. ductal 1.6%; P = 0.026). Thirteen additional HER2^mut cases were identified locally. Twenty-one of these 22 HER2^mut cases were estrogen receptor positive. Sixteen patients [median age 58 (31-74) years and three (2-10) prior metastatic regimens] received neratinib. The CBR was 31% [90% confidence interval (CI), 13%-55%], including one CR, one PR, and three SD ≥24 weeks. Median PFS was 16 (90% CI, 8-31) weeks. Diarrhea (grade 2, 44%; grade 3, 25%) was the most common adverse event. Baseline ctDNA sequencing identified the same HER2^mut in 11 of 14 tumor-positive cases (sensitivity, 79%; 90% CI, 53%-94%) and correctly assigned 32 of 32 informative negative cases (specificity, 100%; 90% CI, 91%-100%). In addition, ctDNA HER2^mut variant allele frequency decreased in nine of 11 paired samples at week 4, followed by an increase upon progression.Conclusions: Neratinib is active in HER2^mut, nonamplified MBC. ctDNA sequencing offers a noninvasive strategy to identify patients with HER2^mut cancers for clinical trial participation. Clin Cancer Res; 23(19); 5687-95. ©2017 AACR.

Phase I study of the combination of balixafortide (CXCR4 inhibitor) and eribulin in HER2-negative metastatic breast cancer (MBC) patients (pts)

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Background: Balixafortide (POL6326) is a cyclic peptide and a potent, selective antagonist of the chemokine receptor CXCR4. Evidence suggests that CXCR4 inhibition interferes with the tumor-protective microenvironment and sensitizes tumor cells to chemotherapy. The combination of balixafortide (B) and eribulin (E) was safe with early signs of efficacy in the dose escalation part of this study. Methods: The expanded cohort of thisopen label phase I study was designed to assess the anti-tumor activity, safety and pharmacokinetics of the addition of the recommended phase 2 dose (RP2D) of B to E in pts with MBC and with any CXCR4 expression level at the tumor site. Patients received E (1.4 mg/m2) on days 2 and 9, flanked by B (5.5 mg/kg) on days 1-3, and 8-10 of 21-day cycles. Results: 24 pts with relapsed MBC (median age 59 [33-82]) were enrolled in the expanded cohort. Median number of prior chemotherapies for MBC was 2 (range 1-3). 20/24 (83%) pts were ER and/or PR positive; 3/24 (13%) pts had TNBC. Objective response rate (ORR) was 33%. 8/24 (33%) pts achieved a partial response and 4/24 (17%) pts had meaningful (≥ 6 months) stable disease for a Clinical Benefit Ratio of 50%. Median duration of treatment was 15.3 weeks (range 5-40) with 11 pts still on treatment. The most common Gr 3-4 adverse events were neutropenia (9/24, 38%) and leucopenia (3/24, 13%); 2 pts had febrile neutropenia and 1 patient died from sepsis. 15/24 (63%) pts experienced histamine-like infusion reactions related to B that were manageable with anti-histamines. Conclusions: The therapeutic activity of this treatment regimen appears promising with an ORR of 33% in patients with advanced MBC. B (5.5 mg/kg) can be combined safely with E (1.4 mg/m2) and the safety profile resembles E monotherapy as previously reported. This is the first study of the treatment combination of E with B in relapsed MBC pts. Further confirmatory studies are being considered. Clinical trial information: NCT01837095.

Abstract P6-12-15: Efficacy results of a phase 1/2 study of glucocorticoid receptor (GR) antagonist mifepristone (MIFE) in combination with eribulin in GR-positive triple-negative breast cancer (TNBC)

Background: GR is variably expressed in TNBC and high expression is associated with poor prognosis in estrogen receptor-negative (ER-) early stage breast cancer. Treatment with mifepristone (MIFE) potentiates the effectiveness of chemotherapy in GR+ TNBC xenografts. Enrollment is complete in this study of patients with GR+ TNBC treated at the recommended Phase 2 dose (RP2D) of MIFE in combination with eribulin. Objectives: To determine the safety, tolerability, pharmacokinetics (PK) and clinical activity of the MIFE plus eribulin combination in pts with GR+ TNBC at the RP2D. Methods: Eligibility: In Part 1 (dose finding), pts with solid tumors; in Part 2 (expansion phase), pts with TNBC (GR result required at time of screening in Part 1, but could be pending at time of screening in Part 2). Up to 5 prior chemotherapy regimens for advanced disease; ECOG PS 0-1; adequate end-organ function. Design: 3 + 3 dose escalation scheme. After a 7-day lead-in of oral daily MIFE alone, MIFE was continued daily and eribulin was given on days 1 and 8 of a 21-day cycle. GR+ was defined as &gt;10% of tumor cells with any intensity of GR staining. Results: 16 pts with metastatic breast cancer were treated in Part 1, and 21 pts with TNBC were treated in Part 2. Median age was 54 (range 30-81). MTD/RP2D was MIFE 300 mg/day + eribulin 1.1 mg/m2. Safety: DLT in Part 1 was neutropenia. Neutropenia occurred in 23/36 total patients (2 Grade [G] 1, 10 G3, 11 G4); 2 instances included neutropenic fever. Recovery of WBC was brisk with growth factor support. Neuropathy was observed in 8 pts (5 G1, 1 G2, 2 G3). Other most common AEs (fatigue, hypokalemia, nausea, alopecia) were mainly G1 or G2; among these, G3/G4 events were limited to fatigue (4 G3), hypokalemia (3 G3 and 1 G4) and nausea (1 G3). There were 2 instances of G1 vaginal bleeding. There was no impact of MIFE on eribulin PK. Efficacy: There were 23 evaluable pts with TNBC across Parts 1 and 2 treated at the RP2D: 21 GR+, 2 GR status unknown; median of 3 prior chemotherapy regimens; 1 patient had received prior eribulin. Responses were: 3 PR, 8 SD, 11 PD and one too early to assess. Median PFS was 9 weeks. Conclusions: MIFE plus eribulin was well tolerated and appears to be an active treatment regimen. Five TNBC patients had a PFS longer than the upper 95% CI for PFS (i.e., &gt;15 wks) reported by Aogi et al. for TNBC treated with eribulin (Annals of Oncology 2012?23:144148). Clinical trial information: NCT02014337.

Citation Format: Han HS, Wilks S, Paplomata E, Modiano MR, Becerra C, Braiteh FS, Spira AI, Pluard TJ, Richards DA, Conzen SD, Baker G, Fishman RS, Marcantonio A, O'Shaughnessy J, Nanda R. Efficacy results of a phase 1/2 study of glucocorticoid receptor (GR) antagonist mifepristone (MIFE) in combination with eribulin in GR-positive triple-negative breast cancer (TNBC) [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P6-12-15.

Prevention of everolimus/exemestane (EVE/EXE) stomatitis in postmenopausal (PM) women with hormone receptor-positive (HR+) metastatic breast cancer (MBC) using a dexamethasone-based mouthwash (MW): Results of the SWISH trial

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Background: Stomatitis is a frequent adverse event (AE) associated with mTOR inhibition. In BOLERO-2 patients (pts) receiving EVE/EXE, all grade (Gr) stomatitis was 67%; 33% had Gr ≥ 2 and 8% Gr 3. Median time to ≥ Gr 2 onset was 15.5 days; incidence of new stomatitis (Gr ≥ 2) plateaued at 6 wks. In a meta-analysis, 89% of first stomatitis events occurred within 8 wks. Topical steroids are used to treat aphthous ulcers; anecdotal use as prophylaxis has been reported. Methods: Eligibility included PM women with HR+ MBC prescribed EVE/EXE. Treatment included EVE 10 mg and EXE 25 mg QD, with 10 mL of commercially available 0.5 mg/5 mL dexamethasone oral solution to swish x 2 min and spit QID for 8 wks starting day 1. Pts completed a daily adherence log, including an oral pain (range 0-10) and normalcy of diet score. The primary endpoint was to compare the incidence of Gr ≥ 2 stomatitis at 8 wks with BOLERO-2 results. Secondary endpoints included MW use by average times/day, EVE/EXE dose intensity, incidence of all Gr stomatitis and time to resolution to Gr ≤ 1. Results: 92 women were enrolled; 86 were evaluable for efficacy. Median age was 61 yrs (range 34-87); median dose intensity was 10 (range 3-10) and 25 mg (range 8-25) for EVE and EXE, respectively. 95% of pts used the MW 3-4 times/day (median MW use/day = 3.95, range 1.9-4). At 8 wks, the rate of ≥ Gr 2 stomatitis was 2.4% (2 pts) with a Gr 1 rate of 18.8%. A comparison of stomatitis incidence by grade between BOLERO-2 and SWISH is shown in the table. In the 75 patients with complete ECOG scores, 88% maintained/improved ECOG status. Mean pain scale score was < 1 at all visits; 88% of pts reported a normal diet at 8 wks. 13% discontinued EVE/EXE due to suspected related AEs (most common: rash, 2%; hyperglycemia, 2%; stomatitis, 2%; and pneumonitis, 1%). Conclusions: Prophylactic use of 0.5 mg/5 mL dexamethasone oral solution markedly decreases the incidence and severity of stomatitis in patients receiving EVE/EXE for MBC and should be considered a new standard of oral care in this setting. Clinical trial information: NCT02069093. [Table: see text]