Miller, Kathy D.

PURPOSE The PALLAS study investigated whether the addition of palbociclib, an oral CDK4/6 inhibitor, to adjuvant endocrine therapy (ET) improves invasive disease-free survival (iDFS) in early hormone receptor-positive (HR+), human epidermal growth factor receptor 2-negative (HER2–) breast cancer. In this analysis, we evaluated palbociclib exposure and discontinuation in PALLAS. METHODS Patients with stage II-III HR+, HER2– disease were randomly assigned to 2 years of palbociclib with adjuvant ET versus ET alone. The primary objective was to compare iDFS between arms. Continuous monitoring of toxicity, dose modifications, and early discontinuation was performed. Association of baseline covariates with time to palbociclib reduction and discontinuation was analyzed with multivariable competing risk models. Landmark and inverse probability weighted per-protocol analyses were performed to assess the impact of drug persistence and exposure on iDFS. RESULTS Of the 5,743 patient analysis population (2,840 initiating palbociclib), 1,199 (42.2%) stopped palbociclib before 2 years, the majority (772, 27.2%) for adverse effects, most commonly neutropenia and fatigue. Discontinuation of ET did not differ between arms. Discontinuations for non–protocol-defined reasons were greater in the first 3 months of palbociclib, and in the first calendar year of accrual, and declined over time. No significant relationship was seen between longer palbociclib duration or ≥ 70% exposure intensity and improved iDFS. In the weighted per-protocol analysis, no improvement in iDFS was observed in patients receiving palbociclib versus not (hazard ratio 0.89; 95% CI, 0.72 to 1.11). CONCLUSION Despite observed rates of discontinuation in PALLAS, analyses suggest that the lack of significant iDFS difference between arms was not directly related to inadequate palbociclib exposure. However, the discontinuation rate illustrates the challenge of introducing novel adjuvant treatments, and the need for interventions to improve persistence with oral cancer therapies.

PURPOSE Palbociclib is a cyclin-dependent kinase 4 and 6 inhibitor approved for advanced breast cancer. In the adjuvant setting, the potential value of adding palbociclib to endocrine therapy for hormone receptor–positive breast cancer has not been confirmed. PATIENTS AND METHODS In the prospective, randomized, phase III PALLAS trial, patients with hormone receptor–positive, human epidermal growth factor receptor 2–negative early breast cancer were randomly assigned to receive 2 years of palbociclib (125 mg orally once daily, days 1-21 of a 28-day cycle) with adjuvant endocrine therapy or adjuvant endocrine therapy alone (for at least 5 years). The primary end point of the study was invasive disease-free survival (iDFS); secondary end points were invasive breast cancer–free survival, distant recurrence-free survival, locoregional cancer-free survival, and overall survival. RESULTS Among 5,796 patients enrolled at 406 centers in 21 countries worldwide over 3 years, 5,761 were included in the intention-to-treat population. At the final protocol-defined analysis, at a median follow-up of 31 months, iDFS events occurred in 253 of 2,884 (8.8%) patients who received palbociclib plus endocrine therapy and in 263 of 2,877 (9.1%) patients who received endocrine therapy alone, with similar results between the two treatment groups (iDFS at 4 years: 84.2% v 84.5%; hazard ratio, 0.96; CI, 0.81 to 1.14; P = .65). No significant differences were observed for secondary time-to-event end points, and subgroup analyses did not show any differences by subgroup. There were no new safety signals for palbociclib in this trial. CONCLUSION At this final analysis of the PALLAS trial, the addition of adjuvant palbociclib to standard endocrine therapy did not improve outcomes over endocrine therapy alone in patients with early hormone receptor–positive breast cancer.

TPS1111 Background: Chest wall recurrence is a subtype of breast cancer that is challenging to treat, and associated with a short duration of response to treatment and an increased risk of development of distant metastases. Given the inflammatory nature of this disease and the association of chest wall disease with lymphovascular invasion, which is correlated with higher programmed cell death 1 (PD-1) expression, we hypothesized that immunotherapy may be beneficial as treatment. Combinations of immunotherapy and chemotherapy have a synergistic effect and demonstrated efficacy in the treatment of metastatic triple negative breast cancer (TNBC). This study is evaluating the efficacy of pembrolizumab, an anti-PD-1 antibody, in combination with carboplatin, in patients with chest wall infiltration from breast cancer. This drug combination has shown efficacy in advanced lung cancer. Methods: This is a multicenter, 2:1 randomized phase II study of pembrolizumab/carboplatin (Arm A, 56 patients) vs. carboplatin (Arm B, 28 patients) in 84 patients with chest wall disease from breast cancer, with or without distant metastases. Patients may have TNBC, hormone receptor positive/HER2 negative (following receipt of 2 prior hormone therapies), or HER2 positive breast cancer (with option to continue trastuzumab on study). Pembrolizumab is administered as 200 mg IV every 3 weeks, and carboplatin as AUC 5 IV every 3 weeks. Patients on Arm A may continue pembrolizumab +/- carboplatin (Arm Ax) after completion of 6 cycles of treatment, while patients in Arm B can cross-over to pembrolizumab (+/- carboplatin) on progression (Arm Bx). Patients must have adequate organ function, performance status ≤ 2, and may have received any number of lines of prior chemotherapy. Patients undergo serial chest wall photography and imaging (CT chest, abdomen, and pelvis, and bone scan) at baseline and every 6 weeks, as well as blood collection for correlative studies and chest wall biopsies at baseline and after 2 cycles of treatment. The primary endpoint is disease control rate (RECIST 1.1) at 18 weeks of treatment, and the study is powered to determine a 20% difference in disease control rates between arms (HR 0.52, a = 0.10, ß = 0.20). An interim analysis will occur for Arm B after 18 patients are enrolled, with a stopping rule for futility. Secondary endpoints include progression-free survival, toxicity (NCI CTCAE), and response based on irRECIST and tumor programmed death ligand 1 (PD-L1) expression. Exploratory objectives include evaluating changes in soluble PD-L1, tumor and peripheral blood immune composition, circulating tumor cells and cell-free DNA, and MYC oncogene expression. This study (NCT03095352) is open at 7 sites in the Translational Breast Cancer Research Consortium (TBCRC). 52 patients are enrolled. Grant funding is provided by Merck and UCSF. Clinical trial information: NCT03095352 .

520 Background: Systemic inflammation may contribute to cancer progression (PMC2803035), including recurrence of early breast cancer (PMC4828958). We hypothesized that inflammatory cytokines and/or chemokines may be associated with distant recurrence (DR). Methods: We performed a case:control study in women with stage II-III Her2-negative breast cancer, all of whom had surgery and adjuvant chemotherapy (doxorubicin/cyclophosphamide, then weekly paclitaxel) with/without bevacizumab, plus endocrine therapy if ER-positive (PMC6118403). Propensity score matching was used to identify approximately 250 case:control pairs (with/without DR). Serum samples obtained before adjuvant chemotherapy were analyzed using the MSD V-Plex Human Cytokine 36-Plex Kit for detection of human cytokines and chemokines involved in the Th1/Th2 pathway, chemotaxis, the Th17 pathway, angiogenesis, and immune system regulation. Conditional logistic regression analysis, with models fit via maximum likelihood, were used to estimate hazard ratios (HRs) and test for associations. Due to skewed nature of cytokines, HRs are reported on log base 2 scale. If adjusted for multiple testing including 36 markers, a p value of < 0.0014 would be required for statistical significance. Results: A total 249 matched pairs (498 patients) were identified. Covariates used for propensity score matching included age, menopausal status (post 54% vs. pre/peri 46%), ER/PR status (one/both pos 64% vs. both neg 36%) tumor size ( < = 2cm 17%, > 2-5cm 67%, > 5cm 16%) nodal status (neg 15%,1-3+ 32%, 4+ 53%), and grade (low 3%, int. 31%, high 66%). The only biomarker associated with a significantly increased DR risk when adjusted for multiple testing was the proinflammatory cytokine IL-6 (HR 1.37, 95% confidence intervals [CI] 1.15, 1.65, p = 0.0006). Others associated with a 2-sided p value < 0.05 included the chemokine MDC(macrophage-derived chemokine/CCL22) (1.90, 95% CI 1.17, 3.1, p = 0.0098), the T helper cell inflammatory cytokine IL-17A (HR 1.36, 95% CI 1.10, 1.67, p = 0.0052), and the cytokine VEGF-A (HR 1.13 for, 95% CI 1.01, 1.27, p = 0.037). There was no statistical interaction between VEGF-A and bevacizumab benefit. The median and mean value for IL-6 was 0.95 and 7.5 pg/ml (range 0.04-2761.24 pg/ml). Conclusions: This analysis provides level 1B evidence indicating that higher levels of the cytokine IL-6 at diagnosis are associated with a significantly higher DR risk in high-risk stage II-III breast cancer despite optimal adjuvant systemic therapy. This provides a foundation for confirmatory validation of IL-6 as a prognostic biomarker, and potentially as a predictive biomarker for testing therapeutic interventions targeting the IL-6/JAK/STAT3 pathway. Supported by NCI U10CA180820,180794,180821; UG1CA189859,232760,233290, 233196; Komen Foundation; Breast Cancer Research Foundation. Clinical trial information: NCT00433511.

Abstract Background: Chest wall recurrence may occur in up to 30% of patients with breast cancer, and is associated with a high morbidity and mortality. We hypothesized that immunotherapy may be beneficial in this setting because of the inflammatory nature of this disease, and the association of chest wall disease with lymphovascular invasion. Combination immunotherapy and chemotherapy may have a synergistic effect. In this study, we combined pembrolizumab, an anti-programmed cell death 1 (PD-1) antibody with carboplatin, in patients with chest wall disease. This combination has previously been shown to be effective in advanced lung cancer. Trial design: This is a 2:1 randomized phase II study of pembrolizumab and carboplatin (Arm A) versus carboplatin alone (Arm B) in patients with chest wall involvement from breast cancer. Pembrolizumab is dosed at 200 mg IV every 3 weeks, and carboplatin is dosed at AUC 5 IV every 3 weeks. Patients on Arm A have the option to continue on pembrolizumab alone after 6 cycles of combination treatment (Arm Ax). Patients on Arm B have the option to cross-over to pembrolizumab (+/- carboplatin) after 6 cycles of carboplatin alone (Arm Bx). Patients with HER2 positive disease may continue trastuzumab in addition to the study treatment. Patients undergo chest wall biopsies and peripheral blood collection for correlative studies at enrollment and after 2 cycles of treatment, and also imaging with CT chest, abdomen, and pelvis, and bone scan every 3 cycles. Eligibility criteria: Patients must have chest wall involvement from breast cancer, with or without distant metastases. Patients may have triple-negative breast cancer, hormone receptor positive, HER2- disease (after two prior lines of hormone therapy), or refractory HER2 positive disease. Patients may have received any number of lines of prior chemotherapy. A prior platinum is allowed as long as there was not disease progression on this agent. Specific Aims: 1. (Primary aim) Disease control rate in the chest wall and other distant sites at 18 weeks of treatment using RECIST 1.1 criteria, 2. progression-free survival, 3. toxicity, 4. response based on tumor PD-L1 expression, and 5. response based on irRECIST. Exploratory aims include evaluating: 1. Soluble PD-L1 expression, 2. changes in tumor and peripheral blood immune composition, 3. peripheral blood circulating tumor cells, 4. peripheral blood cell-free DNA, and 5. the association of MYC with PD-1 and TIM-3 on tumor cells, based on preclinical data to suggest that MYC may upregulate these inflammatory markers. Statistical Methods: 84 patients (56 in Arm A and 28 in Arm B) are being enrolled at 7 sites in the Translational Breast Cancer Research Consortium. The study is powered to determine a 20% difference in disease control rates between arms (HR 0.52, α= 0.10, ß=0.20). A futility analysis was originally planned to occur for Arm B after 18 patients are enrolled, but a subsequent amendment has enabled an earlier assessment after 14 patients were enrolled. Accrual: Present accrual is 40 patients. (NCT03095352). This trial is funded in part by Merck and a Development Program Grant from the University of California San Francisco. Contact information: Neelima Vidula, MD, Massachusetts General Hospital, nvidula@mgh.harvard.edu Citation Format: Neelima Vidula, Rita Nanda, Kathy Miller, Paula Pohlmann, Vandana Abramson, Leisha A. Emens, Ben H. Park, Minetta C. Liu, Andrei Goga, Hope S. Rugo. Translational breast cancer research consortium 044 trial: Randomized phase 2 study of pembrolizumab and carboplatin versus carboplatin alone for chest wall recurrence of breast cancer [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr OT-13-09.

e19132 Background: The Functional Assessment of Cancer Therapy–General has an item about patient tolerability of treatment: “I am bothered by side effects of treatment” (GP5). We examined the predictive value of this single item for early treatment discontinuation in clinical trials. Methods: GP5 level prior to protocol therapy (rated using a 5-point Likert scale) and treatment start/end dates and off treatment reason data at each treatment phase were drawn from five phase III clinical trials conducted by ECOG-ACRIN. In the present analysis, GP5 was dichotomized as 0 = “Not at all”/“A little bit” and 1 = “Somewhat”/“Quite a bit”/“Very Much”. Early treatment discontinuation was defined either as receiving less than protocol specified cycles of treatment when maximum cycles specified in the protocol (E1A06 induction, E1912 induction, E1609 induction, E1105 induction, E5103 adjuvant), analyzed using logistic regression via odds ratio [OR]), or treatment cessation for reasons other than progressive disease or death when treatment continued until progression or intolerability (E1A06 maintenance, E1912 maintenance, E1609 maintenance, E1105 maintenance), analyzed using Cox proportional hazard model via hazard ratio [HR]. Results: GP5 prior to treatment was significantly associated with early discontinuation of E1A06 maintenance, E1609 maintenance, E1912 maintenance, and E1912 induction. No significant association was found for other therapies examined in the study. Conclusions: High GP5 level prior to treatment is associated with higher likelihood of early treatment discontinuation in patients who have received previous treatment. The limited predictive value of GP5 for treatment naïve patients is more limited, serial on-treatment assessment should be considered in this setting. Clinical trial information: NCT00602641 . [Table: see text]

TPS1114 Background: Immunotherapy combined with chemotherapy is being studied in metastatic breast cancer, and may have durable outcomes. Chest wall recurrence represents a difficult to treat subtype of breast cancer with a poor prognosis, with lymphovascular invasion in the primary tumor a significant risk factor. Given the inflammatory nature of this disease and the association of programmed cell death 1 (PD-1) expression with lymphovascular invasion, we hypothesized that the combination of pembrolizumab, an anti-PD-1 antibody, with carboplatin may be effective as treatment for breast cancer chest wall recurrences. Methods: This randomized phase II study is enrolling 84 patients with breast cancer involving the chest wall, who may also have distant metastases. Patients receive treatment with pembrolizumab 200 mg and carboplatin AUC 5 every 3 weeks for 6 cycles (Arm A, n = 56) followed by maintenance pembrolizumab +/- carboplatin (Arm Ax), or carboplatin AUC 5 every 3 weeks for 6 cycles (Arm B, n = 28) with an option to cross-over to pembrolizumab +/- carboplatin on progression (Arm Bx). Patients with all disease subtypes, triple-negative, hormone receptor positive/HER2- after 2 prior lines of hormone therapy, and HER2+ disease (with the option to continue trastuzumab) are eligible, with no limit on the number of prior therapies. Prior platinum chemotherapy is allowed in the absence of overt disease progression. Patients undergo clinical assessment with every cycle of treatment including chest wall photography, scans (CT chest, abdomen, and pelvis) every 2 cycles, and have peripheral blood and chest wall biopsies collected at baseline and the start of cycle 3 for correlative studies. The primary endpoint is the disease control rate in the chest wall and distant sites at 18 weeks of treatment based on RECIST 1.1. The study is powered to determine a 20% difference in disease control between arms (hazard ratio 0.52, α = 0.10, β = 0.20). Additional endpoints include response by tumor programmed death ligand 1 (PD-L1) status and irRECIST, progression-free survival, and toxicity. Chest wall tumor samples will be analyzed for changes in tumor immune composition, and PD-L1 and MYC oncogene expression, based on preclinical data to suggest that PD-L1 may be upregulated by MYC. Peripheral blood samples will be evaluated for changes in PD-L1 expression, cell-free DNA, and circulating tumor cells with treatment. The study is enrolling patients at 7 sites within the Translational Breast Cancer Research Consortium (TBCRC), with current enrollment of 38/84 patients. Clinical trial information: NCT03095352 .

Abstract Background: Chest wall recurrence can occur as a complication of breast cancer. This type of breast cancer is difficult to treat with short-lived responses to therapy, and associated with the development of distant metastases. Better therapies are needed in this setting. Immune checkpoint inhibition is being explored in breast cancer, with an immunotherapy agent currently approved for triple-negative breast cancer (TNBC). We hypothesize that pembrolizumab, an anti-programmed cell death 1 (PD-1) antibody, may be effective in treating chest wall recurrence of breast cancer given the inflammatory nature of this disease and high expression of PD-1 seen in tumors with lymphovascular invasion that may predispose patients to chest wall recurrence. Platinum chemotherapy may augment anti-tumor immunity, with the combination of pembrolizumab and carboplatin shown to be effective in advanced lung cancer. This study is evaluating the efficacy of pembrolizumab and carboplatin for breast cancer patients with chest wall disease. Methods: In this phase II study, 84 patients are being randomized 2:1 to treatment with pembrolizumab in combination with carboplatin (Arm A) versus carboplatin alone (Arm B) with an option to cross over to pembrolizumab alone (Arm Bx) on progression. Pembrolizumab is dosed at 200 mg IV every 3 weeks, and carboplatin is dosed at AUC 5 IV every 3 weeks. Patients may have TNBC, hormone receptor positive (HR)+/HER2- breast cancer that has progressed on 2 prior lines of hormone therapy, or refractory HER2+ breast cancer (may continue herceptin). Patients may have distant metastases, but must have surgically unresectable disease. Prior chest wall radiation is allowed. The primary endpoint is to determine the disease control rate (chest wall and distant sites) at 18 weeks of treatment. Patients undergo chest wall assessments with photography of skin lesions with every cycle of treatment, and imaging (CT chest, abdomen, and pelvis, and bone scan) every 2 cycles to evaluate for progression. The study is powered to determine a 20% difference in disease control rates between arms A and B (hazard ratio of 0.52, α= 0.10, β= 0.20). Secondary endpoints include response stratified by tumor programmed death ligand 1 (PD-L1) expression, progression free survival, response by irRECIST, and toxicity. The study incorporates many translational studies using chest wall biopsy tissue collected at baseline and after 2 cycles of treatment, as well as correlative blood tests, including assessing changes in tumor and blood PD-L1 expression, circulating cell-free DNA, circulating tumor cells, soluble PD-L1 expression, and changes in the expression of MYC, an oncogene that may upregulate the expression of PD-1. Patients are currently being enrolled at 7 sites in the TBCRC. As of July 2019, 30 patients are enrolled. This study is supported by Merck and the TBCRC. (NCT03095352). Citation Format: Neelima Vidula, Rita Nanda, Kathy Miller, Vandana Abramson, Paula Pohlmann, Adam Brufsky, Ben Park, Minetta Liu, Andrei Goga, Hope S. Rugo. Pembrolizumab in combination with carboplatin versus carboplatin alone in breast cancer patients with chest wall disease: Translational Breast Cancer Research Consortium (TBCRC) 44 trial [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 OT2-04-05.

9508 Background: Chemotherapy-related amenorrhea (CRA) is associated with infertility and may impact treatment decision-making. We investigated whether anti-mullerian hormone (AMH) levels before chemotherapy predict likelihood of CRA. Methods: 591 patients enrolled on the quality of life substudy of ECOG5103, which randomized breast cancer patients to doxorubicin-cyclophosphamide followed by paclitaxel: 1) alone; 2) with concurrent bevacizumab; or 3) with prolonged bevacizumab. 144 of the 195 women who reported a period <12 months before enrollment consented to serum collection prior to chemotherapy. AMH was measured in 143 with available serum. Participants self-reported menstrual frequency at 12 and 18 months after enrollment. 12-month CRA was defined as no menses for 6 months before the 12-month survey, and 18-month CRA as no menses for 6 months before the 18-month survey. Fisher’s exact test was used to identify associations with CRA. Results: Of the 143, 16 were excluded due to bilateral oophorectomy or initiation of ovarian function suppression within 12 months, and 2 due to missing data at 12 months. In the remaining 125, median age at enrollment was 45 (range 25-55). 103 (82%) had CRA at 12 months, including 68% of patients </= 45 (43/63) and 97% of patients >45 (60/62). Median pre-chemotherapy AMH was 0.11 (range 0.01-8.63). 12-month CRA was more likely in women who received bevacizumab (p<0.01), were >45 (p<0.01), and had AMH </=0.11 (p<0.01) pre-treatment. Hormonal tx was not associated with 12-month CRA (p=0.63). 100 patients were eligible for 18-month CRA analysis: 81 (81%) had CRA, including 63% of patients </= 45 (33/52) and 100% (48/48) of patients >45. 18-month CRA was more likely in women >45 (p<0.01) and with AMH </=0.11 (p<0.01) pre-treatment. Bevacizumab (p=0.15) and hormonal tx (p=0.07) were not statistically significant predictors of 18-month CRA. Conclusions: Pre-chemotherapy AMH predicts risk of CRA at 12 and 18 months, and is a promising biomarker of ovarian reserve in young breast cancer survivors. Longer studies will be needed to ascertain whether lower pre-treatment AMH is associated with increased risk of later infertility. Clinical trial information: NCT00433511.

6527 Background: Biomarker information can risk stratify patients based on potential for benefits/toxicity from therapy. Ideally, a biomarker will identify those who benefit with limited toxicity. However, the impact of biomarkers is unclear when indicting individuals with greatest benefit are also at increased risk for toxicity. Methods: We surveyed participants at 18 month follow-up in the Decision-Making/Quality of Life (DM-QOL) component of ECOG5103, a RCT where patients were randomized to receive adjuvant chemotherapy for breast cancer with either placebo or bevacizumab (in 2 schedules). We asked patients for the preferred treatment in two hypothetical scenarios: 1) preference for chemo A or chemo A + B without biomarker information; 2) preference for chemo A or chemo A+B when participants tested positive for a “B-receptor” which increased both the benefit and toxicity of chemo A+B. McNemar’s test was used to examine changes in preferences. Results: 439 patients completed both scenarios on 18-month survey. The Table shows the treatment preferences in each scenario. The positive biomarker information in scenario 2 led 60/439 (14%) participants to switch their preference. The main reason for treatment preference in scenario 2 was greater benefits of chemo A+B (64%), the lower risks with chemo A (20%) and positive biomarker (10%). Among participants who changed preference, those randomized to receive bevacizumab were more likely to switch to chemo A in scenario 2. Conclusions: Information about a positive biomarker, indicating increased benefit and increased risk from additional chemo, did not significantly change participants’ preferred treatment. All participants were involved in a large placebo controlled double blind trial and the majority (70%) preferred the most aggressive course of treatment in both scenarios. Whether patients not enrolled in the trial would be more sensitive to the increased risk information is unclear. [Table: see text]