Luciana Molinero

Abstract 2859: Inhibition of PD-L1 by MPDL3280A leads to clinical activity in patients with metastatic triple-negative breast cancer (TNBC)

Proceedings: AACR 106th Annual Meeting 2015; April 18-22, 2015; Philadelphia, PA Introduction: TNBC is a mutationally complex breast cancer subtype with poor prognosis and no current targeted therapy options. Compared with other intrinsic breast cancer subtypes, TNBC has higher programmed death-ligand 1 (PD-L1) expression levels, which may hinder antitumor T-cell responses. MPDL3280A is a monoclonal anti-PDL1 antibody, engineered for optimized efficacy and safety, that blocks signaling through the PD-L1/PD-1 and PD-L1/B7.1 pathways. Methods: MPDL3280A was tested in a metastatic TNBC expansion cohort as part of a multicenter Phase Ia study. Pts received MPDL3280A at 15 mg/kg, 20 mg/kg or 1200 mg flat dose IV q3w. AEs were summarized for the safety follow-up duration from the first dose to 30 days after the last dose before the clinical cutoff on Sept 2, 2014. Responses were assessed by RECIST v1.1 criteria in pts who received MPDL3280A by Jul 21, 2014, evaluable for efficacy (≥ 6-wk follow-up). PD-L1 expression on tumor-infiltrating immune cells (ICs) at baseline was centrally evaluated by IHC in archival or fresh biopsies, and pts were scored as PD-L1 IHC (IC) 0, 1, 2 or 3. Peripheral biomarkers were assayed using FACS and multiplex immunoassays. Results: In the TNBC cohort, 27 pts were selectively enrolled. These pts had a median age of 48 y (29-82 y) and were evaluable for safety; 52% had ECOG PS 0 and 44% had ECOG PS 1. Visceral and bone metastases were present at baseline in 59% and 11% of pts, respectively. In addition, 85% received ≥ 4 prior systemic regimens (neoadjuvant, adjuvant or metastatic), including anthracyclines (78%), taxanes (82%) and platinum agents (15% cisplatin, 41% carboplatin). All-grade treatment-related AEs occurred in 67% of pts, most frequently fatigue (22%), pyrexia (15%), neutropenia (15%) and nausea (15%). 11% of pts experienced a Grade 3-5 related AE (5 Grade 3 events: adrenal insufficiency, neutropenia, nausea, vomiting, decreased WBC count; 1 Grade 5 pulmonary hypertension event in a pt with an atrial septal defect). Among 21 efficacy-evaluable PD-L1 IHC 2 or 3 pts (13 IHC 2 and 8 IHC 3), the unconfirmed RECIST ORR was 24% (95% CI, 8% to 47%); 3 PRs and 2 CRs were observed. Response duration ranged from 0.1+ to 41.6+ wks, with the median not yet reached. Pts with evidence of durable nonclassical responses suggestive of pseudoprogression were also observed. Overall, the 24-wk PFS rate was 33% (95% CI, 12% to 53%). Biomarker analysis revealed transient elevation of plasma cytokines and proliferating CD8 cells following MPDL3280A treatment. Updated clinical data, including PD-L1-negative pts, will be presented. Conclusions: MPDL3280A was generally well tolerated and demonstrated promising efficacy in pretreated metastatic PD-L1 IHC 2 or 3 TNBC pts. Furthermore, circulating biomarker analyses revealed pharmacodynamic responses to MPDL3280A. Clinical evaluation of MPDL3280A in metastatic PD-L1 IHC 0 or 1 TNBC is ongoing ([NCT01375842][1]). Citation Format: Leisha A. Emens, Fadi S. Braiteh, Philippe Cassier, Jean-Pierre Delord, Joseph Paul Eder, Marcella Fasso, Yuanyuan Xiao, Yan Wang, Luciana Molinero, Daniel S. Chen, Ian Krop. Inhibition of PD-L1 by MPDL3280A leads to clinical activity in patients with metastatic triple-negative breast cancer (TNBC). [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2859. doi:10.1158/1538-7445.AM2015-2859 [1]: /lookup/external-ref?link_type=CLINTRIALGOV&access_num=NCT01375842&atom=%2Fcanres%2F75%2F15_Supplement%2F2859.atom

Abstract 2986: Atezolizumab in metastatic TNBC (mTNBC): Long-term clinical outcomes and biomarker analyses

Introduction. Triple negative breast cancer (TNBC) has a poor prognosis and limited treatment options. Atezolizumab (atezo) is a humanized mAb that inhibits the binding of PD-L1 to PD-1 and B7.1, thus restoring tumor-specific T-cell immunity. Atezo was evaluated in an expansion cohort of mTNBC patients (pts) in a Phase Ia study (NCT01375842). Methods. Enrollment was initially limited to TNBC pts with PD-L1 on ≥5% of tumor-infiltrating immune cells (IC2/3), then opened to pts regardless of PD-L1 status. Pts received atezo IV in 1L or 2L+ q3w at 15 or 20 mg/kg or 1200 mg for 1 y with option to be retreated at PD, or until loss of clinical benefit. ORR was assessed by RECIST v1.1 and irRC, to capture non-conventional responses. Baseline PD-L1 expression on IC was centrally scored as IC0/1/2/3 (VENTANA SP142 assay). Pretreatment tumors and on-therapy biopsies were evaluated for TILs, CD8 T cells and macrophages by IHC. Results. As of Mar 31, 2016, 115 mTNBC pts were safety evaluable; atezo was generally well tolerated. There were no additional safety signals from prior report (Emens AACR 2015). 112 pts with FU ≥12 wk were evaluable for response. Based on irRC, ORR in 1L and 2L+ pts were 26% and 11%, respectively. ORR for PD-L1 IC2/3 pts were 17% vs 8% in IC0/1. mDoR was 21.1 mo (3 to 34+). mOS of responders (n=15) was not reached (4+ to 37+ mo) with no deaths as of data cutoff. mOS of non-responders who lived ≥ 6 wk (n=87) was 9 mo (1+ to 19+ mo). OS rates in all pts at 1, 2, and 3 y were 41%, 22% and 22%, respectively. OS rates at 1, 2, and 3 y for PD-L1 IC2/3 were 45%, 28% and 28%, respectively. Pts whose tumors had >10% TILs or ≥1.35% CD8 in the tumor center trended toward higher ORR and longer OS. Atezo increased intratumoral TILs, CD8, macrophages and IC PD-L1 expression, but no response association was observed. Conclusions. In mTNBC, atezo was well tolerated. Responders showed durable clinical benefit. Response rates were higher in 1L or PD-L1 IC2/3 pts. Baseline TILs and CD8 were associated with greater clinical benefit. Citation Format: Peter Schmid, Cristina Cruz, Fadi S. Braiteh, Joseph Paul Eder, Sara Tolaney, Irene Kuter, Rita Nanda, Cathie Chung, Philippe Cassier, Jean-Pierre Delord, Michael Gordon, Yijin Li, Bo Liu, Carol O’Hear, Marcella Fasso, Luciana Molinero, Leisha A. Emens. Atezolizumab in metastatic TNBC (mTNBC): Long-term clinical outcomes and biomarker analyses [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2986. doi:10.1158/1538-7445.AM2017-2986

Abstract P2-11-06: Safety and clinical activity of atezolizumab (anti-PDL1) in combination with nab-paclitaxel in patients with metastatic triple-negative breast cancer

Background: Metastatic triple-negative breast cancer (mTNBC) is associated with poor prognosis, and chemotherapy remains the mainstay of treatment. Cancer immunotherapy represents a promising treatment approach for mTNBC, which is characterized by a high mutation rate, increased levels of tumor-infiltrating lymphocytes and high programmed death ligand-1 (PD-L1) expression levels. Atezolizumab (atezo; MPDL3280A) is a humanized monoclonal antibody that can restore tumor-specific T-cell immunity by inhibiting the binding of PD-L1 to PD-1. Atezo has demonstrated durable responses as monotherapy in mTNBC (Emens et al, AACR 2015). In addition, high objective response rates (ORRs) and durable responses have been observed with atezo plus chemotherapy in patients with non-small cell lung cancer (Liu et al, ASCO 2015). This study is the first combination trial of a checkpoint inhibitor with chemotherapy in patients with mTNBC. Methods: This arm of a multicenter, multi-arm Phase Ib study (NCT01633970) evaluated atezo in combination with weekly nab-paclitaxel in patients with mTNBC. Primary endpoints were safety and tolerability, with secondary endpoints of PK and clinical activity. Key eligibility criteria included measurable disease, ECOG PS 0/1 and ≤ 2 prior cytotoxic regimens. Patients received atezo 800 mg q2w (days 1 and 15) with nab-paclitaxel 125 mg/m2 q1w (days 1, 8 and 15) for 3 weeks in 4-week cycles, continued until loss of clinical benefit. If nab-paclitaxel was discontinued due to toxicity, atezo could be continued as monotherapy. ORR was assessed by RECIST v1.1. PD-L1 expression was scored at 4 diagnostic levels based on PD-L1 staining on tumor cells and tumor-infiltrating immune cells with the SP142 immunohistochemistry assay. Results: As of February 10, 2015, 11 patients were evaluable for safety. All patients were women with a median age of 58 y (range, 32-75 y). No unexpected or dose-limiting toxicities were observed. The median duration of safety follow-up was 79 days (range, 27-182 days). The efficacy-evaluable population consisted of 5 patients who had ≥ 1 scan and ≥ 3 months follow-up. Four PRs and 1 SD were observed. By the next data cutoff of June 15, 2015, 21 patients will have been enrolled (7 in the safety cohort and 14 in the expansion cohort). All patients in the expansion cohort were required to undergo serial biopsies for correlative analyses. Approximately 21 and 19 patients will be evaluable for safety and efficacy, respectively. Updated safety, efficacy and biomarker data will be presented. Conclusions: Preliminary results indicate that the combination of atezo plus nab-paclitaxel is tolerable with promising activity in patients with mTNBC. Based on these results and the observed activity of single-agent atezo in these patients, the combination of atezo and nab-paclitaxel is being evaluated in a Phase III study (NCT02425891) of patients with previously untreated mTNBC. Sponsor: Genentech, Inc. ClinicalTrials.gov: NCT01633970. Citation Format: Adams S, Diamond J, Hamilton E, Pohlmann P, Tolaney S, Molinero L, Zou W, Liu B, Waterkamp D, Funke R, Powderly J. Safety and clinical activity of atezolizumab (anti-PDL1) in combination with nab-paclitaxel in patients with metastatic triple-negative breast cancer. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P2-11-06.

T cell-NF-κB activation is required for tumor control in vivo

BackgroundT cells have the capacity to eliminate tumors but the signaling pathways by which they do so are incompletely understood. T cell priming requires activation of the transcription factors AP-1, NFAT and NF-κB downstream of the TCR, but whether activation of T cell-NF-κB in vivo is required for tumor control has not been addressed. In humans and mice with progressively growing tumors, the activity of T cell-intrinsic NF-κB is often reduced. However, it is not clear if this is causal for an inability to reject transformed cells, or if it is a consequence of tumor growth. T cell-NF-κB is important for T cell survival and effector differentiation and plays an important role in enabling T cells to reject cardiac and islet allografts, suggesting the possibility that it may also be required for tumor elimination. In this study, we tested whether normal T cell-NF-κB activation is necessary for the rejection of tumors whose growth is normally controlled by the immune system.MethodsMice with genetically impaired T cell-NF-κB activity were subcutaneously injected with MC57-SIY tumor cells. Tumor growth was measured over time, and the anti-tumor immune response was evaluated using flow cytometry and cytokine detection assays.ResultsMice with impaired T cell-NF-κB activity were unable to reject tumors that were otherwise eliminated by wildtype mice, despite equal accumulation of tumor-reactive T cells. In addition, specific impairment of NF-κB signaling downstream of the TCR was sufficient to prevent tumor rejection. Tumor antigen-specific T cell-IFN-γ and TNF-α production, as well as cytotoxic ability, were all reduced in mice with impaired T cell-NF-κB, suggesting an important role for this transcription factor in the effector differentiation of tumor-specific effector T cells.ConclusionsOur results have identified the NF-κB pathway as an important signaling axis in T cells, required for the elimination of growing tumors in vivo. Maintaining or enhancing T cell-NF-κB activity may be a promising avenue for anti-tumor immunotherapy.

Gene expression profiling in BRAF-mutated melanoma reveals patient subgroups with poor outcomes to vemurafenib that may be overcome by cobimetinib plus vemurafenib

Purpose: The association of tumor gene expression profiles with progression-free survival (PFS) outcomes in patients with BRAFV600-mutated melanoma treated with vemurafenib or cobimetinib combined with vemurafenib was evaluated. Experimental Design: Gene expression of archival tumor samples from patients in four trials (BRIM-2, BRIM-3, BRIM-7, and coBRIM) was evaluated. Genes significantly associated with PFS (P < 0.05) were identified by univariate Cox proportional hazards modeling, then subjected to unsupervised hierarchical clustering, principal component analysis, and recursive partitioning to develop optimized gene signatures. Results: Forty-six genes were identified as significantly associated with PFS in both BRIM-2 (n = 63) and the vemurafenib arm of BRIM-3 (n = 160). Two distinct signatures were identified: cell cycle and immune. Among vemurafenib-treated patients, the cell-cycle signature was associated with shortened PFS compared with the immune signature in the BRIM-2/BRIM-3 training set [hazard ratio (HR) 1.8; 95% confidence interval (CI), 1.3–2.6, P = 0.0001] and in the coBRIM validation set (n = 101; HR, 1.6; 95% CI, 1.0–2.5; P = 0.08). The adverse impact of the cell-cycle signature on PFS was not observed in patients treated with cobimetinib combined with vemurafenib (n = 99; HR, 1.1; 95% CI, 0.7–1.8; P = 0.66). Conclusions: In vemurafenib-treated patients, the cell-cycle gene signature was associated with shorter PFS. However, in cobimetinib combined with vemurafenib-treated patients, both cell cycle and immune signature subgroups had comparable PFS. Cobimetinib combined with vemurafenib may abrogate the adverse impact of the cell-cycle signature. Clin Cancer Res; 23(17); 5238–45. ©2017 AACR.

Atezolizumab Plus nab-Paclitaxel in the Treatment of Metastatic Triple-Negative Breast Cancer With 2-Year Survival Follow-up: A Phase 1b Clinical Trial

Importance The humanized monoclonal antibody atezolizumab targets programmed death-ligand 1 and has demonstrated durable single-agent activity in a subset of metastatic triple-negative breast cancers. To extend the observed activity, combinatorial approaches are being tested with standard cytotoxic chemotherapies known to induce immunogenic tumor cell death. Objective To examine the safety, tolerability, and preliminary clinical activity of atezolizumab plus nab-paclitaxel in metastatic triple-negative breast cancers. Design, Setting, and Participants This phase 1b multicohort study enrolled 33 women with stage IV or locally recurrent triple-negative breast cancers and 0 to 2 lines of prior chemotherapy in the metastatic setting from December 8, 2014, to April 30, 2017, at 11 sites in the United States. The median follow-up was 24.4 months (95% CI, 22.1-28.8 months). Interventions Patients received concurrent intravenous atezolizumab and intravenous nab-paclitaxel (minimum 4 cycles). Main Outcomes and Measures The primary end point was safety and tolerability. Secondary end points included best overall response rate by Response Evaluation Criteria in Solid Tumors, version 1.1; objective response rate; duration of response; disease control rate; progression-free survival; overall survival; and biomarker analyses. Results The 33 women had a median age of 55 years (range, 32-84 years) and received 1 or more doses of atezolizumab. All patients (100%) experienced at least 1 treatment-related adverse event, 24 patients (73%) experienced grade 3/4 adverse events, and 7 patients (21%) had grade 3/4 adverse events of special interest. No deaths were related to study treatment. The objective response rate was 39.4% (95% CI, 22.9%-57.9%), and the median duration of response was 9.1 months (95% CI, 2.0-20.9 months). The disease control rate was 51.5% (95% CI, 33.5%-69.2%). Median progression-free survival and overall survival were 5.5 months (95% CI, 5.1-7.7 months) and 14.7 months (95% CI, 10.1-not estimable), respectively. Concurrent nab-paclitaxel neither significantly changed biomarkers of the tumor immune microenvironment (programmed death-ligand 1, tumor-infiltrating lymphocytes, CD8) nor impaired atezolizumab systemic immune activation (expansion of proliferating CD8+ T cells, increase of CXCL10 chemokine). Conclusions and Relevance In this phase 1b trial for metastatic triple-negative breast cancers, the combination of atezolizumab plus nab-paclitaxel had a manageable safety profile. Antitumor responses were observed, including in patients previously treated with a taxane. Trial Registration ClinicalTrials.gov identifier: NCT01633970

Long-term Clinical Outcomes and Biomarker Analyses of Atezolizumab Therapy for Patients With Metastatic Triple-Negative Breast Cancer: A Phase 1 Study

Importance Atezolizumab (anti–programmed cell death ligand 1 [PD-L1]) is well tolerated and clinically active in multiple cancer types. Its safety and clinical activity in metastatic triple-negative breast cancer (mTNBC) has not been reported. Objective To evaluate the safety, clinical activity, and biomarkers associated with the use of single-agent atezolizumab in patients with mTNBC. Design, Setting, and Participants Women with mTNBC (defined by investigator assessment) were enrolled between January 2013 and February 2016 in a multicohort open-label, phase 1 study at US and European academic medical centers. Median follow-up was 25.3 months (range, 0.4-45.6 months). Eligible patients regardless of line of therapy had measurable disease by Response Evaluation Criteria in Solid Tumors, version 1.1; Eastern Cooperative Oncology Group performance status of 0 to 1; and a representative tumor sample for assessment of immune cell (IC) PD-L1 expression. Interventions Atezolizumab was given intravenously every 3 weeks until unacceptable toxic effects or loss of clinical benefit. Main Outcomes and Measures Primary outcome was safety and tolerability. Activity and exploratory outcomes included objective response rate (ORR), duration of response, progression-free survival (PFS), and overall survival (OS). Outcomes were assessed in all patients and in key patient subgroups. Results Among 116 evaluable patients (median age, 53 years [range, 29-82 years]), treatment-related adverse events occurred in 73 (63%); 58 (79%) were grade 1 to 2. Most adverse events occurred within the first treatment year. The ORRs were numerically higher in first-line (5 of 21 [24%]) than in second-line or greater patients (6 of 94 [6%]). Median duration of response was 21 months (range, 3 to ≥38 months). Median PFS was 1.4 (95% CI, 1.3-1.6) months by RECIST and 1.9 (95% CI, 1.4-2.5) months by irRC. In first-line patients, median OS was 17.6 months (95% CI, 10.2 months to not estimable). Patients with PD-L1 expression of at least 1% tumor-infiltrating ICs had higher ORRs and longer OS (12% [11 of 91]; 10.1 [95% CI, 7.0-13.8] months, respectively) than those with less than 1% ICs (0 of 21; 6.0 [95% CI, 2.6-12.6] months, respectively). High levels of ICs (>10%) were independently associated with higher ORRs and longer OS. Conclusions and Relevance Single-agent atezolizumab was well tolerated and provided durable clinical benefit in patients with mTNBC with stable or responding disease and in earlier lines of treatment. Trial Registration ClinicalTrials.gov identifier: NCT01375842

A PK/PD Analysis of Circulating Biomarkers and Their Relationship to Tumor Response in Atezolizumab‐Treated non‐small Cell Lung Cancer Patients

To assess circulating biomarkers as predictors of antitumor response to atezolizumab (anti‐programmed death‐ligand 1 (PD‐L1), Tecentriq) serum pharmacokinetic (PK) and 95 plasma biomarkers were analyzed in 88 patients with relapsed/refractory non‐small cell lung cancer (NSCLC) receiving atezolizumab i.v. q3w (10–20 mg/kg) in the PCD4989g phase I clinical trial. Following exploratory analyses, two plasma biomarkers were chosen for further study and correlation with change in tumor size (the sum of the longest diameter) was assessed in a pharmacokinetic/pharmacodynamic (PK/PD) tumor modeling framework. When longitudinal kinetics of biomarkers and tumor size were modeled, tumor shrinkage was found to significantly correlate with area under the curve (AUC), baseline factors (metastatic sites, liver metastases, and smoking status), and relative change in interleukin (IL)‐18 level from baseline at day 21 (RCFBIL‐18,d21). Although AUC was a major predictor of tumor shrinkage, the effect was estimated to dissipate with an average half‐life of 80 days, whereas RCFBIL‐18,d21 seemed relevant to the duration of the response.

Abstract PD6-01: Prevalence of PDL1 and tumor infiltrating lymphocytes (TILs) in primary and metastatic TNBC

Background: Metastatic Triple Negative Breast Cancer (TNBC) is an aggressive breast cancer subtype with a high unmet medical need and limited therapeutic options. PDL1 on immune cells (IC) and TILs were associated with activity to the anti-PDL1 mAB atezolizumab in mTNBC (Schmid AACR 2017). PDL1 IC >=1% is the diagnostic hypothesis for TNBC atezolizumab studies. The goal of the current project was to evaluate the prevalence of PDL1 and TILs in primary and metastatic TNBC samples. Methods: FFPE tumor tissue from pathology documented TNBC tissues were centrally tested for PDL1 IHC on tumor cells (TC) and infiltrating immune cells (IC) (VENTANA SP142 assay) and quantified as percentage of tumor area. TILs were evaluated as a percentage of tumor area and PD-L1 gene (CD274) expression was quantified by Fluidigm. Results: 669 tumors were evaluable for PD-L1 by IHC and TILs. 280 samples were annotated as primary tumors and 179 as metastases with 210 denoted as unknown. PDL1 IC and TC immunostaining was correlated to PD-L1 transcript expression (r = 0.55 and r = 0.51, respectively). 84% of samples had no tumor cells expressing PDL1 and 16% had at least 1% of PDL1 in TC. 44% of the samples had no PDL1 in the immune cells, 35% expressed PDL1 IC [31% to Conclusions: Prevalence of PDL1 IHC is similar between primary and metastatic TNBC samples. Although PDL1 IC and TILs are highly correlated, TILs are less prevalent in metastases compared to primary tissue. Anatomical location may influence prevalence of both PDL1 IC and TILs. Concordance of PDL1 in matched pairs is high, suggesting PDL1 IC may be a stable biomarker. Citation Format: Li Y, Chang C-W, Tran D, Denker M, Hegde P, Molinero L. Prevalence of PDL1 and tumor infiltrating lymphocytes (TILs) in primary and metastatic TNBC [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr PD6-01.