Abemaciclib in combination with pembrolizumab for HR+, HER2- metastatic breast cancer: Phase 1b study.

This nonrandomized, open-label, multi-cohort Phase 1b study (NCT02779751) investigated the safety and efficacy of abemaciclib plus pembrolizumab with/without anastrozole in patients with hormone receptor-positive (HR+), human epidermal growth factor receptor 2-negative (HER2-) metastatic breast cancer (MBC) without prior CDK4 and 6 inhibitor exposure. Patients were divided into two cohorts: treatment naïve (cohort 1) and pretreated (cohort 2). Patients received abemaciclib plus pembrolizumab with (cohort 1) or without (cohort 2) anastrozole over 21-day cycles. The primary objective was safety, and secondary objectives included efficacy and pharmacokinetics (PK). Cohort 1/2 enrolled 26/28 patients, respectively. Neutropenia (30.8/28.6%), AST increase (34.6/17.9%), ALT increase (42.3/10.7%), and diarrhea (3.8/10.7%) were the most frequent grade ≥3 adverse events in cohort 1/2, respectively. A total of two deaths occurred, which investigators attributed to treatment-related adverse events (AEs), both in cohort 1. Higher rates of all grade and grade ≥3 interstitial lung disease (ILD)/pneumonitis were observed compared to previously reported with abemaciclib and pembrolizumab monotherapy. The PK profiles were consistent between cohorts and with previous monotherapy studies. In cohorts 1/2, the overall response rate and disease control rate were 23.1/28.6% and 84.6/82.1%, respectively. Median progression-free survival and overall survivals were 8.9 (95% CI: 3.9-11.1) and 26.3 months (95% CI: 20.0-31.0) for cohort 2; cohort 1 data are immature. Abemaciclib plus pembrolizumab demonstrated antitumor activity, but high rates of ILD/pneumonitis and severe transaminase elevations occurred with/without anastrozole compared to the previous reporting. Benefit/risk analysis does not support further evaluation of this combination in the treatment of HR+, HER2- MBC.We thank the patients and families who participated in this study, caregivers, the study investigators, and their staff, and the JPCE (NCT02779751) clinical trial team. Pembrolizumab was provided by Merck & Co., Inc., Kenilworth, NJ, USA. We thank Anne Chain from the Department of Quantitative Pharmacology & PharmacometricsImmune/Oncology, Merck & Co., Inc., Kenilworth, NJ, USA for her contributions to this work, which included pembrolizumab PK and ADA analysis. This work and medical writing support was funded by Eli Lilly and Company.S

Survival, pathologic response, and genomics in CALGB 40601 (Alliance), a neoadjuvant Phase III trial of paclitaxel-trastuzumab with or without lapatinib in HER2-positive breast cancer

PURPOSE CALGB 40601 assessed whether dual versus single human epidermal growth factor receptor 2 (HER2) -targeting drugs added to neoadjuvant chemotherapy increased pathologic complete response (pCR). Here, we report relapse-free survival (RFS), overall survival (OS), and gene expression signatures that predict pCR and survival. PATIENTS AND METHODS Three hundred five women with untreated stage II and III HER2-positive breast cancer were randomly assigned to receive weekly paclitaxel combined with trastuzumab plus lapatinib (THL), trastuzumab (TH), or lapatinib (TL). The primary end point was pCR, and secondary end points included RFS, OS, and gene expression analyses. mRNA sequencing was performed on 264 pretreatment samples. RESULTS One hundred eighteen patients were randomly allocated to THL, 120 to TH, and 67 to TL. At more than 7 years of follow-up, THL had significantly better RFS and OS than did TH (RFS hazard ratio, 0.32; 95% CI, 0.14 to 0.71; P 5.005; OS hazard ratio, 0.34; 95% CI, 0.12 to 0.94; P 5.037), with no difference between TH and TL. Of 688 previously described gene expression signatures, significant associations were found in 215 with pCR, 45 with RFS, and only 22 with both pCR and RFS (3.2%). Specifically, eight immune signatures were significantly correlated with a higher pCR rate and better RFS. Among patients with residual disease, the immunoglobulin G signature was an independent, good prognostic factor, whereas the HER2-enriched signature, which was associated with a higher pCR rate, showed a significantly shorter RFS. CONCLUSION In CALGB 40601, dual HER2-targeting resulted in significant RFS and OS benefits. Integration of intrinsic subtype and immune signatures allowed for the prediction of pCR and RFS, both overall and within the residual disease group. These approaches may provide means for rational escalation and de-escalation treatment strategies in HER2-positive breast cancer

Integrated analysis of RNA and DNA from the phase III trial CALGB 40601 identifies predictors of response to trastuzumab-based neoadjuvant chemotherapy in HER2-positive breast cancer

Purpose: Response to a complex trastuzumab-based regimen is affected by multiple features of the tumor and its microenvironment. Developing a predictive algorithm is key to optimizing HER2-targeting therapy. Experimental Design: We analyzed 137 pretreatment tumors with mRNA-seq and DNA exome sequencing from CALGB 40601, a neoadjuvant phase III trial of paclitaxel plus trastuzumab with or without lapatinib in stage II to III HER2-positive breast cancer. We adopted an Elastic Net regularized regression approach that controls for covarying features within high-dimensional data. First, we applied 517 known gene expression signatures to develop an Elastic Net model to predict pCR, which we validated on 143 samples from four independent trials. Next, we performed integrative analyses incorporating clinicopathologic information with somatic mutation status, DNA copy number alterations (CNA), and gene signatures. Results: The Elastic Net model using only gene signatures predicted pCR in the validation sets (AUC ¼ 0.76). Integrative analyses showed that models containing gene signatures, clinical features, and DNA information were better pCR predictors than models containing a single data type. Frequently selected variables from the multiplatform models included amplifications of chromosome 6p, TP53 mutation, HER2-enriched subtype, and immune signatures. Variables predicting resistance included Luminal/ERþ features. Conclusions: Models using RNA only, as well as integrated RNA and DNA models, can predict pCR with improved accuracy over clinical variables. Somatic DNA alterations (mutation, CNAs), tumor molecular subtype (HER2E, Luminal), and the microenvironment (immune cells) were independent predictors of response to trastuzumab and paclitaxel-based regimens. This highlights the complexity of predicting response in HER2-positive breast cancer

Local-regional recurrence in women with small node-negative, HER2-positive breast cancer: results from a prospective multi-institutional study (the APT trial).

PurposeWomen with HER2-positive breast cancer treated prior to effective anti-HER2 therapy have higher rates of local-regional recurrence (LRR) than those with HER2-negative disease. Effective systemic therapy, however, has been shown to decrease LRR. This study examines LRR in women with HER2-positive breast cancer treated on a single-arm prospective multicenter trial of adjuvant trastuzumab (H) and paclitaxel (T).MethodsPatients with HER2-positive tumors ≤ 3.0 cm with negative axillary nodes or micrometastatic disease were eligible. Systemic therapy included weekly T and H for 12 weeks followed by continuation of H to complete 1 year. Radiation therapy (RT) was required following breast-conserving surgery (BCS), but dose and fields were not specified. Disease-free survival (DFS) and LRR-free survival were calculated using the Kaplan-Meier method.ResultsOf the 410 patients enrolled from September 2007 to September 2010, 406 initiated protocol therapy and formed the basis of this analysis. A total of 272 (67%) had hormone receptor-positive tumors. Of 162 patients undergoing mastectomy, local therapy records were unavailable for two. None of the 160 for whom records were available received RT. Among 244 BCS patients, detailed RT records were available for 217 (89%). With a median follow-up of 6.5 years, 7-year DFS was 93.3% (95% CI 90.4-96.2), and LRR-free survival was 98.6% (95% CI 97.4-99.8).ConclusionLRR in this select group of early-stage patients with HER2-positive disease receiving effective anti-HER2 therapy is extremely low. If confirmed in additional studies, future investigational efforts should focus on de-escalating local therapy

Updated standardized definitions for efficacy endpoints in adjuvant breast cancer clinical trials: STEEP Version 2.0

Purpose The Standardized Definitions for Efficacy End Points (STEEP) criteria, established in 2007, provide standardized definitions of adjuvant breast cancer clinical trial end points. Given the evolution of breast cancer clinical trials and improvements in outcomes, a panel of experts reviewed the STEEP criteria to determine whether modifications are needed.Methods We conducted systematic searches of ClinicalTrials.gov for adjuvant systemic and local-regional therapy trials for breast cancer to investigate if the primary end points reported met STEEP criteria. On the basis of common STEEP deviations, we performed a series of simulations to evaluate the effect of excluding non-breast cancer deaths and new nonbreast primary cancers from the invasive disease-free survival end point.Results Among 11 phase III breast cancer trials with primary efficacy end points, three had primary end points that followed STEEP criteria, four used STEEP definitions but not the corresponding end point names, and four used end points that were not included in the original STEEP manuscript. Simulation modeling demonstrated that inclusion of second nonbreast primary cancer can increase the probability of incorrect inferences, can decrease power to detect clinically relevant efficacy effects, and may mask differences in recurrence rates, especially when recurrence rates are low.Conclusion We recommend an additional end point, invasive breast cancer-free survival, which includes all invasive disease-free survival events except second nonbreast primary cancers. This end point should be considered for trials in which the toxicities of agents are well-known and where the risk of second primary cancer is small. Additionally, we provide end point recommendations for local therapy trials, low-risk populations, noninferiority trials, and trials incorporating patient-reported outcomes

Endocrine Therapy Synergizes with SMAC Mimetics to Potentiate Antigen Presentation and Tumor Regression in Hormone Receptor-Positive Breast Cancer.

UNLABELLED: Immunotherapies have yet to demonstrate significant efficacy in the treatment of hormone receptor-positive (HR+) breast cancer. Given that endocrine therapy (ET) is the primary approach for treating HR+ breast cancer, we investigated the effects of ET on the tumor immune microenvironment (TME) in HR+ breast cancer. Spatial proteomics of primary HR+ breast cancer samples obtained at baseline and after ET from patients enrolled in a neoadjuvant clinical trial (NCT02764541) indicated that ET upregulated β2-microglobulin and influenced the TME in a manner that promotes enhanced immunogenicity. To gain a deeper understanding of the underlying mechanisms, the intrinsic effects of ET on cancer cells were explored, which revealed that ET plays a crucial role in facilitating the chromatin binding of RelA, a key component of the NF-κB complex. Consequently, heightened NF-κB signaling enhanced the response to interferon-gamma, leading to the upregulation of β2-microglobulin and other antigen presentation-related genes. Further, modulation of NF-κB signaling using a SMAC mimetic in conjunction with ET augmented T-cell migration and enhanced MHC-I-specific T-cell-mediated cytotoxicity. Remarkably, the combination of ET and SMAC mimetics, which also blocks prosurvival effects of NF-κB signaling through the degradation of inhibitors of apoptosis proteins, elicited tumor regression through cell autonomous mechanisms, providing additional support for their combined use in HR+ breast cancer. SIGNIFICANCE: Adding SMAC mimetics to endocrine therapy enhances tumor regression in a cell autonomous manner while increasing tumor immunogenicity, indicating that this combination could be an effective treatment for HR+ patients with breast cancer

Impact of the Addition of Carboplatin and/or Bevacizumab to Neoadjuvant Once-per-Week Paclitaxel Followed by Dose-Dense Doxorubicin and Cyclophosphamide on Pathologic Complete Response Rates in Stage II to III Triple-Negative Breast Cancer: CALGB 40603 (Alliance)

Purpose: One third of patients with triple-negative breast cancer (TNBC) achieve pathologic complete response (pCR) with standard neoadjuvant chemotherapy (NACT). CALGB 40603 (Alliance), a 2 x 2 factorial, open-label, randomized phase II trial, evaluated the impact of adding carboplatin and/or bevacizumab. Patients and Methods: Patients (N = 443) with stage II to III TNBC received paclitaxel 80 mg/m2 once per week (wP) for 12 weeks, followed by doxorubicin plus cyclophosphamide once every 2 weeks (ddAC) for four cycles, and were randomly assigned to concurrent carboplatin (area under curve 6) once every 3 weeks for four cycles and/or bevacizumab 10 mg/kg once every 2 weeks for nine cycles. Effects of adding these agents on pCR breast (ypT0/is), pCR breast/axilla (ypT0/isN0), treatment delivery, and toxicities were analyzed. Results: Patients assigned to either carboplatin or bevacizumab were less likely to complete wP and ddAC without skipped doses, dose modification, or early discontinuation resulting from toxicity. Grade 3 neutropenia and thrombocytopenia were more common with carboplatin, as were hypertension, infection, thromboembolic events, bleeding, and postoperative complications with bevacizumab. Employing one-sided P values, addition of either carboplatin (60% v 44%; P � .0018) or bevacizumab (59% v 48%; P =.0089) significantly increased pCR breast, whereas only carboplatin (54% v 41%; P = .0029) significantly raised pCR breast/axilla. More-than-additive interactions between the two agents could not be demonstrated. Conclusion: In stage II to III TNBC, addition of either carboplatin or bevacizumab to NACT increased pCR rates, but whether this will improve relapse-free or overall survival is unknown. Given results from recently reported adjuvant trials, further investigation of bevacizumab in this setting is unlikely, but the role of carboplatin could be evaluated in definitive studies, ideally limited to biologically defined patient subsets most likely to benefit from this agent

Impact of the Addition of Carboplatin and/or Bevacizumab to Neoadjuvant Once-per-Week Paclitaxel Followed by Dose-Dense Doxorubicin and Cyclophosphamide on Pathologic Complete Response Rates in Stage II to III Triple-Negative Breast Cancer: CALGB 40603 (Alliance)

One third of patients with triple-negative breast cancer (TNBC) achieve pathologic complete response (pCR) with standard neoadjuvant chemotherapy (NACT). CALGB 40603 (Alliance), a 2 × 2 factorial, open-label, randomized phase II trial, evaluated the impact of adding carboplatin and/or bevacizumab

Biomarker analyses in the phase III ASCENT study of sacituzumab govitecan versus chemotherapy in patients with metastatic triple-negative breast cancer

Background: The pivotal phase III ASCENT trial demonstrated improved survival outcomes associated with sacituzumab govitecan (SG), an anti-trophoblast cell-surface antigen 2 (anti-Trop-2) antibody-drug conjugate linked with the topoisomerase-inhibitor SN-38, over single-agent chemotherapy treatment of physician's choice (TPC) in previously treated metastatic triple-negative breast cancer (mTNBC). This prespecified, exploratory biomarker analysis from the ASCENT trial evaluates the association between tumor Trop-2 expression and germline BRCA1/2 mutation status with clinical outcomes. Patients and methods: Patients with mTNBC refractory to or progressing after two or more prior chemotherapies, with one or more in the metastatic setting, were randomized to receive SG (10 mg/kg intravenously days 1 and 8, every 21 days) or TPC (capecitabine, eribulin, vinorelbine, or gemcitabine) until disease progression/unacceptable toxicity. Biopsy or surgical specimens were collected at study entry to determine Trop-2 expression level using a validated immunohistochemistry assay and histochemical scoring. Germline BRCA1/2 mutation status was collected at baseline. Results: Of 468 assessable patients, 290 had Trop-2 expression data [64% (n = 151 SG) versus 60% (n = 139 TPC)] and 292 had known BRCA1/2 mutation status [63% (n = 149 SG) versus 61% (n = 143 TPC)]. Median progression-free survival in SG- versus TPC-treated patients was 6.9, 5.6, and 2.7 months versus 2.5, 2.2, and 1.6 months for high, medium, and low Trop-2 expression, respectively. Median overall survival (14.2, 14.9, and 9.3 months versus 6.9, 6.9, and 7.6 months) and objective response rates (44%, 38%, and 22% versus 1%, 11%, and 6%) were numerically higher with SG versus TPC in patients with high, medium, and low Trop-2 expression, respectively. Efficacy outcomes were numerically higher with SG versus TPC in patients with and without germline BRCA1/2 mutations. Conclusions: SG benefits patients with previously treated mTNBC expressing high/medium Trop-2 compared with standard-of-care chemotherapy and regardless of germline BRCA1/2 mutation status. The small number of patients with low Trop-2 expression precludes definitive conclusions on the benefit of SG in this subgroup

Adjuvant Paclitaxel and Trastuzumab for Node-Negative, HER2-Positive Breast Cancer

No single standard treatment exists for patients with small, node-negative, human epidermal growth factor receptor type 2 (HER2)–positive breast cancers, because most of these patients have been ineligible for the pivotal trials of adjuvant trastuzumab