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Grade 3 or 4 adverse events possibly related to refametinib or sorafenib, occurring in {greater than or equal to}2 patients in either cohort

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Overview of dose-limiting toxicities and adverse events leading to discontinuation and relationship to study treatment

Refametinib geometric mean (% coefficient of variation) multiple-dose pharmacokinetic data on day 1 of course 2

Incidence of treatment-emergent adverse events, all grades, occurring in {greater than or equal to}20% of patients in either cohort

CTC enumeration and pERK analysis in course 1

pERK levels in hair follicles by dose level and course

Purpose:To assess the response to pexidartinib treatment in six cohorts of adult patients with advanced, incurable solid tumors associated with colony-stimulating factor 1 receptor (CSF1R) and/or KIT proto-oncogene receptor tyrosine kinase activity.Patients and Methods:From this two-part phase I, multicenter study, pexidartinib, a small-molecule tyrosine kinase inhibitor that targets CSF1R, KIT, and FMS-like tyrosine kinase 3 (FLT3), was evaluated in six adult patient cohorts (part 2, extension) with advanced solid tumors associated with dysregulated CSF1R. Adverse events, pharmacokinetics, and tumor responses were assessed for all patients; patients with tenosynovial giant cell tumor (TGCT) were also evaluated for tumor volume score (TVS) and patient-reported outcomes (PRO). CSF1 transcripts and gene expression were explored in TGCT biopsies.Results:Ninety-one patients were treated: TGCT patients (n = 39) had a median treatment duration of 511 days, while other solid tumor patients (n = 52) had a median treatment duration of 56 days. TGCT patients had response rates of 62% (RECIST 1.1) and 56% (TVS) for the full analysis set. PRO assessments for pain showed improvement in patient symptoms, and 76% (19/25) of TGCT tissue biopsy specimens showed evidence of abnormal CSF1 transcripts. Pexidartinib treatment of TGCT resulted in tumor regression and symptomatic benefit in most patients. Pexidartinib toxicity was manageable over the entire study.Conclusions:These results offer insight into outcome patterns in cancers whose biology suggests use of a CSF1R inhibitor. Pexidartinib results in tumor regression in TGCT patients, providing prolonged control with an acceptable safety profile.

Supplemental Figure 1. Distribution of EGFR extracellular domain (ECD) mutations in ctDNA samples from patients with CRC. Supplemental Figure 2. Response to crizotinib in a patient with small bowel adenocarcinoma and GOPC-ROS1 fusion. Supplemental Figure 3. Detection of copy number amplification is associated with increased ctDNA fraction. Supplemental Table 1. List of 62 genes sequenced in this study using the FoundationACT ctDNA assay. Supplemental Table 2. Genomic alterations detected in temporally matched ctDNA and tissue samples.

Supplementary Data from Results from Phase I Extension Study Assessing Pexidartinib Treatment in Six Cohorts with Solid Tumors including TGCT, and Abnormal CSF1 Transcripts in TGCT

Figure S1. shows total epirubicin concentrations (mean {plus minus} SD) at the end of infusion of 170 mg/m2 NC-6300 across cycles.

Table S1. shows progression Free Survival in individual subjects. Table S2. show exposures to epirubicinol in subjects who received infusion of NC-6300. Figure S1. shows total epirubicin concentrations (mean {plus minus} SD) at the end of infusion of 170 mg/m2 NC-6300 across cycles. Figure S2. shows mean Change in EORTC QLQ-C30 Score from Baseline.

Refametinib geometric mean (% coefficient of variation) single-dose pharmacokinetic data on day 1 of course 1

Sorafenib geometric mean (% coefficient of variation) multiple-dose pharmacokinetic data on day 1 of course 2

Purpose:Atezolizumab [anti–programmed death-ligand 1 (anti-PD-L1)] is well tolerated and efficacious in multiple cancers, but has not been previously evaluated in metastatic castration-resistant prostate cancer (mCRPC). This study examined the safety, efficacy, and biomarkers of atezolizumab monotherapy for mCRPC.Patients and Methods:This phase Ia, open-label, dose-escalation and dose-expansion study (PCD4989g) enrolled patients with mCRPC who had progressed on sipuleucel-T or enzalutamide. Atezolizumab was given intravenously every 3 weeks until confirmed disease progression or loss of clinical benefit. Prespecified endpoints included safety, efficacy, biomarker analyses, and radiographic assessments.Results:All 35 evaluable patients [median age, 68 years (range, 45–83 years)] received atezolizumab after ≥1 prior line of therapy; 62.9% of patients had received ≥3 prior lines. Treatment-related adverse events occurred in 21 patients (60.0%), with no deaths. One patient had a confirmed partial response (PR) per RECIST 1.1, and 1 patient had a PR per immune-related response criteria. The confirmed 50% PSA response rate was 8.6% (3 patients). Median overall survival (OS) was 14.7 months [95% confidence interval (CI): 5.9–not evaluable], with a 1-year OS rate of 52.3% (95% CI: 34–70); 2-year OS was 35.9% (95% CI: 13–59). Median follow-up was 13.0 months (range, 1.2–28.1 months). Biomarker analyses showed that atezolizumab activated immune responses; however, a composite biomarker failed to reveal consistent correlations with efficacy.Conclusions:Atezolizumab was generally well tolerated in patients with mCRPC, with a safety profile consistent with other tumor types. In heavily pretreated patients, atezolizumab monotherapy demonstrated evidence of disease control; however, its limited efficacy suggests a combination approach may be needed.

Purpose:NC-6300 is a novel nanoparticle formulation of epirubicin that has a pH-sensitive linker conjugated to epirubicin. It exhibits selective tumor accumulation owing to enhanced permeability and retention effect. We conducted a phase 1b trial to determine MTD and recommended phase II dose (RP2D) of NC-6300 monotherapy in advanced, metastatic, or unresectable solid tumors, including soft-tissue sarcomas.Patients and Methods:This phase 1b dose-escalation trial of NC-6300 monotherapy employed a Bayesian continuous reassessment method design. NC-6300 was administered on day 1 of every 21-day cycle, with epirubicin-equivalent dose increments from 125 to 215 mg/m2. Safety, efficacy, quality of life, and pharmacokinetic profile of NC-6300 monotherapy were evaluated.Results:Twenty-nine subjects (16 male) were enrolled: 17 with soft-tissue sarcoma, one with osteosarcoma, and 11 with other solid tumors. Observed dose-limiting toxicities included thrombocytopenia, stomatitis, lung infection, and febrile neutropenia. The most common grade 3/4 adverse events were neutropenia (59%), anemia (24%), thrombocytopenia (24%), and febrile neutropenia (21%). MTD and RP2D were determined to be 185 mg/m2 and 150 mg/m2, respectively. The objective response rate in the evaluable population was 11%. Partial response was observed in angiosarcoma and endometrial stromal sarcoma. A dose-dependent increase was observed in both total and released epirubicin concentrations.Conclusions:NC-6300 was well tolerated with a manageable side effect profile, despite the MTD and RP2D being higher than conventional epirubicin doses. A signal of preliminary activity was observed in angiosarcoma. NC-6300 warrants further investigation in patients with advanced solid tumors, including sarcoma.

Purpose: Genomic profiling of tumor biopsies from advanced gastrointestinal and anal cancers is increasingly used to inform treatment. In some cases, tissue biopsy can be prohibitive, and we sought to investigate whether analysis of blood-derived circulating tumor DNA (ctDNA) may provide a minimally invasive alternative.Experimental Design: Hybrid capture–based genomic profiling of 62 genes was performed on blood-based ctDNA from 417 patients with gastrointestinal carcinomas to assess the presence of genomic alterations (GA) and compare with matched tissue samples.Results: Evidence of ctDNA was detected in 344 of 417 samples (82%), and of these, ≥1 reportable GA was detected in 89% (306/344) of samples. Frequently altered genes were TP53 (72%), KRAS (35%), PIK3CA (14%), BRAF (8%), and EGFR (7%). In temporally matched ctDNA and tissue samples available from 25 patients, 86% of alterations detected in tissue were also detected in ctDNA, including 95% of short variants, but only 50% of amplifications. Conversely, 63% of alterations detected in ctDNA were also detected in matched tissue. Examples demonstrating clinical utility are presented.Conclusions: Genomic profiling of ctDNA detected potentially clinically relevant GAs in a significant subset of patients with gastrointestinal carcinomas. In these tumor types, most alterations detected in matched tissue were also detected in ctDNA, and with the exception of amplifications, ctDNA sequencing routinely detected additional alterations not found in matched tissue, consistent with tumor heterogeneity. These results suggest feasibility and utility of ctDNA testing in advanced gastrointestinal cancers as a complementary approach to tissue testing, and further investigation is warranted. Clin Cancer Res; 24(8); 1881–90. ©2018 AACR.

Background Sasanlimab is a monoclonal antibody that binds to the programmed cell death receptor 1 (PD-1). Anti-PD-1 monoclonal antibodies have improved patient clinical outcomes; however, not all treated patients derive clinical benefit. Further insights on potential biomarkers beyond PD-L1 expression levels would help to identify the patients most likely to respond to treatment. Objective This study evaluated tumor biopsies from patients treated with intravenous or subcutaneous sasanlimab to identify biomarkers of response and characterize pharmacodynamic activity. Methods Anti-PD-1/PD-ligand 1 (PD-L1)-naive patients with advanced solid tumors received sasanlimab intravenously at 1, 3, or 10 mg/kg every 3 weeks (n = 23) or subcutaneously at 300 mg every 4 weeks (n = 15). Best tumor percentage change from baseline was determined by RECIST. Whole-exome DNA and RNA sequencing were performed in tumor samples collected from treated patients at protocol-defined timepoints. PD-L1 and CD8 protein expression were evaluated in tumor biopsies by immunohistochemistry. Associations with response were assessed by linear regression analysis. Results Baseline tumor mutational burden (TMB), as well as PD-L1 and CD8 expression, were significantly associated with response to sasanlimab across the multiple dose levels, routes of administration, and range of tumor types evaluated. TMB is an independent biomarker from the various tumor inflammatory genes and signatures evaluated. Gene set enrichment analysis showed that higher baseline expression levels of genes related to the interferon-γ and PD-1 signaling pathways and the cell cycle were significantly associated with response to sasanlimab across tumor types. No differences were observed between routes of administration with regard to response to sasanlimab for the biomarkers of interest (TMB, PD-L1, CD8, and interferon-γ signature). Evaluation of pharmacodynamic changes showed increased tumor expression of genes enriched in adaptive immune response pathways. Conclusions Our findings indicate an active, immunomodulatory mechanism for the anti-PD-1 antibody sasanlimab across different tumor types and routes of administration. Trial Registration ClinicalTrials.gov identifier NCT02573259; registered October 2015. Supplementary Information The online version contains supplementary material available at 10.1007/s11523-021-00833-2.

Purpose: Atezolizumab [anti–programmed death-ligand 1 (anti-PD-L1)] is well tolerated and efficacious in multiple cancers, but has not been previously evaluated in metastatic castration-resistant prostate cancer (mCRPC). This study examined the safety, efficacy, and biomarkers of atezolizumab monotherapy for mCRPC. Patients and Methods: This phase Ia, open-label, dose-escalation and dose-expansion study (PCD4989g) enrolled patients with mCRPC who had progressed on sipuleucel-T or enzalutamide. Atezolizumab was given intravenously every 3 weeks until confirmed disease progression or loss of clinical benefit. Prespecified endpoints included safety, efficacy, biomarker analyses, and radiographic assessments. Results: All 35 evaluable patients [median age, 68 years (range, 45–83 years)] received atezolizumab after ≥1 prior line of therapy; 62.9% of patients had received ≥3 prior lines. Treatment-related adverse events occurred in 21 patients (60.0%), with no deaths. One patient had a confirmed partial response (PR) per RECIST 1.1, and 1 patient had a PR per immune-related response criteria. The confirmed 50% PSA response rate was 8.6% (3 patients). Median overall survival (OS) was 14.7 months [95% confidence interval (CI): 5.9–not evaluable], with a 1-year OS rate of 52.3% (95% CI: 34–70); 2-year OS was 35.9% (95% CI: 13–59). Median follow-up was 13.0 months (range, 1.2–28.1 months). Biomarker analyses showed that atezolizumab activated immune responses; however, a composite biomarker failed to reveal consistent correlations with efficacy. Conclusions: Atezolizumab was generally well tolerated in patients with mCRPC, with a safety profile consistent with other tumor types. In heavily pretreated patients, atezolizumab monotherapy demonstrated evidence of disease control; however, its limited efficacy suggests a combination approach may be needed.

Introduction/Background* The accelerated US Food and Drug Administration approval of pembrolizumab validated the efficacy of anti-PD-(L)1 therapy for patients with recurrent/metastatic cervical cancer; however, the objective response rate (ORR) with pembrolizumab was 14.3% in patients with PD-L1–expressing tumours. Human papillomavirus infection is implicated in >95% of cervical cancers and is linked to upregulation of TGF-β signalling. Bintrafusp alfa is a first-in-class bifunctional fusion protein composed of the extracellular domain of the TGF-βRII receptor (a TGF-β ‘trap’) fused to a human immunoglobulin G1 monoclonal antibody blocking PD-L1. We report pooled safety and efficacy in patients with pretreated, immune checkpoint inhibitor-naive, recurrent/metastatic cervical cancer treated with bintrafusp alfa in phase 1 (INTR@PID 001; NCT02517398) and phase 2 (study 012; NCT03427411) studies. Methodology Patients received bintrafusp alfa 0.3-30 mg/kg (phase 1 dose escalation) or 1200 mg every 2 weeks (phase 1 dose expansion and phase 2) until progressive disease, unacceptable toxicity, or withdrawal. Treatment past progression was allowed. Primary endpoints were safety (phase 1 dose escalation) and best overall response per RECIST 1.1 (phase 1 dose expansion and phase 2). Result(s)* As of May 15, 2020 (phase 1) and December 22, 2020 (phase 2), 39 patients had received bintrafusp alfa for a median duration of 2.8 months (range, 0.5-19.3). The median follow-up to data cutoff was 35.0 months and 24.1 months for the phase 1 and phase 2 studies, respectively. All patients had received prior anticancer therapy; 16 (41.0%) had received ≥3 regimens. Confirmed ORR was 28.2% (table 1); responses occurred irrespective of Moore criteria (phase 1), tumour histology, prior bevacizumab treatment, or radiation treatment. Median overall survival was 13.4 months. No new safety signals and no treatment-related deaths were observed; side effects were manageable. Conclusion* Bintrafusp alfa had a manageable safety profile and demonstrated clinical activity in patients with heavily pretreated, immune checkpoint inhibitor-naive recurrent/metastatic cervical cancer. © 2021 American Society of Clinical Oncology, Inc. Reused with permission. This abstract was accepted and previously presented at the 2021 ASCO Annual Meeting. All rights reserved.

Purpose: To assess the response to pexidartinib treatment in six cohorts of adult patients with advanced, incurable solid tumors associated with colony-stimulating factor 1 receptor (CSF1R) and/or KIT proto-oncogene receptor tyrosine kinase activity. Patients and Methods: From this two-part phase I, multicenter study, pexidartinib, a small-molecule tyrosine kinase inhibitor that targets CSF1R, KIT, and FMS-like tyrosine kinase 3 (FLT3), was evaluated in six adult patient cohorts (part 2, extension) with advanced solid tumors associated with dysregulated CSF1R. Adverse events, pharmacokinetics, and tumor responses were assessed for all patients; patients with tenosynovial giant cell tumor (TGCT) were also evaluated for tumor volume score (TVS) and patient-reported outcomes (PRO). CSF1 transcripts and gene expression were explored in TGCT biopsies. Results: Ninety-one patients were treated: TGCT patients (n = 39) had a median treatment duration of 511 days, while other solid tumor patients (n = 52) had a median treatment duration of 56 days. TGCT patients had response rates of 62% (RECIST 1.1) and 56% (TVS) for the full analysis set. PRO assessments for pain showed improvement in patient symptoms, and 76% (19/25) of TGCT tissue biopsy specimens showed evidence of abnormal CSF1 transcripts. Pexidartinib treatment of TGCT resulted in tumor regression and symptomatic benefit in most patients. Pexidartinib toxicity was manageable over the entire study. Conclusions: These results offer insight into outcome patterns in cancers whose biology suggests use of a CSF1R inhibitor. Pexidartinib results in tumor regression in TGCT patients, providing prolonged control with an acceptable safety profile.

PF-06647263, a novel antibody-drug conjugate consisting of an anti-EFNA4 antibody linked to a calicheamicin payload, has shown potent antitumor activity in human xenograft tumor models, including triple-negative breast cancer (TNBC). In the dose-escalation part 1 of this multicenter, open-label, phase I study (NCT02078752), successive cohorts of patients (n, 48) with advanced solid tumors and no available standard therapy received PF-06647263 every 3 weeks (Q3W) or every week (QW), following a modified toxicity probability interval (mTPI) method (initial dosing: 0.015 mg/kg Q3W). Primary objective in part 1 was to estimate the maximum tolerated dose (MTD) and select the recommended phase 2 dose (RP2D). In part 2 (dose-expansion cohort), 12 patients with pretreated, metastatic TNBC received PF-06647263 at the RP2D to further evaluate tumor response and overall safety. PF-06647263 QW administration (n, 23) was better tolerated than the Q3W regimen (n, 25) with only 1 DLT reported (thrombocytopenia). The most common AEs with the QW regimen (fatigue, nausea, vomiting, mucosal inflammation, thrombocytopenia, and diarrhea) were mostly mild to moderate in severity. The MTD was not estimated. PF-06647263 exposures increased in a dose-related manner across the doses evaluated. The RP2D was determined to be 0.015 mg/kg QW. Six (10%) patients achieved a confirmed partial response and 22 (36.7%) patients had stable disease. No correlations were observed between tumor responses and EFNA4 expression levels. Study findings showed manageable safety and favorable PK for PF-06647263 administered QW at the RP2D, with preliminary evidence of limited antitumor activity in patients with TNBC and ovarian cancer.

Purpose Metastatic cancers of unknown primary or with unclear diagnoses pose diagnostic and management challenges, often leading to poor outcomes. Studies of the 92-gene assay have demonstrated improved diagnostic accuracy compared with standard pathology techniques and improved survival in patients treated on the basis of assay results. The current study assessed the clinical impact of the 92-gene assay on diagnostic and treatment decisions for patients with unknown or uncertain diagnoses. Methods Patients in this prospective, multi-institutional, decision-impact study included those for whom the 92-gene assay was ordered as part of routine care. Participating physicians completed electronic case report forms that contained standardized, specialty-specific questionnaires. Data collection included patient and tumor characteristics and clinical history. The key study objective of clinical impact was calculated on the basis of changes in final diagnosis and treatment after testing. Results Data collection included 444 patients, 107 physicians (73 oncologists and 34 pathologists), and 28 sites. Molecular diagnoses from 22 different tumor types and subtypes across all cases were provided in 95.5% of patients with a reportable result (n = 397). Physicians reported that the 92-gene assay was used broadly for diagnostic dilemmas that ranged from single suspected tumor type (29%) to a differential diagnosis of two or more suspected tumor types (30%) or cancers of unknown primary (41%). Integration of 92-gene assay results led to a change in the recommended treatment in 47% of patients. Conclusion Findings from this clinical utility study demonstrate that the 92-gene assay led to a change in treatment decisions in every other patient case. These data additionally define the role of this assay in clinical practice and strongly support the consideration of molecular tumor typing in the diagnosis and treatment planning of patients with metastatic cancer with unknown or uncertain diagnosis.

Purpose: NC-6300 is a novel nanoparticle formulation of epirubicin that has a pH-sensitive linker conjugated to epirubicin. It exhibits selective tumor accumulation owing to enhanced permeability and retention effect. We conducted a phase 1b trial to determine MTD and recommended phase II dose (RP2D) of NC-6300 monotherapy in advanced, metastatic, or unresectable solid tumors, including soft-tissue sarcomas. Patients and Methods: This phase 1b dose-escalation trial of NC-6300 monotherapy employed a Bayesian continuous reassessment method design. NC-6300 was administered on day 1 of every 21-day cycle, with epirubicin-equivalent dose increments from 125 to 215 mg/m2. Safety, efficacy, quality of life, and pharmacokinetic profile of NC-6300 monotherapy were evaluated. Results: Twenty-nine subjects (16 male) were enrolled: 17 with soft-tissue sarcoma, one with osteosarcoma, and 11 with other solid tumors. Observed dose-limiting toxicities included thrombocytopenia, stomatitis, lung infection, and febrile neutropenia. The most common grade 3/4 adverse events were neutropenia (59%), anemia (24%), thrombocytopenia (24%), and febrile neutropenia (21%). MTD and RP2D were determined to be 185 mg/m2 and 150 mg/m2, respectively. The objective response rate in the evaluable population was 11%. Partial response was observed in angiosarcoma and endometrial stromal sarcoma. A dose-dependent increase was observed in both total and released epirubicin concentrations. Conclusions: NC-6300 was well tolerated with a manageable side effect profile, despite the MTD and RP2D being higher than conventional epirubicin doses. A signal of preliminary activity was observed in angiosarcoma. NC-6300 warrants further investigation in patients with advanced solid tumors, including sarcoma.

Investigating targeted therapies can be challenging due to diverse tumor mutations and slow patient accrual for clinical studies. The Signature Program is a series of 8 phase 2, agent-specific basket protocols using a rapid study start-up approach involving no predetermined study sites. Each protocol evaluated 1 agent (buparlisib, dovitinib, binimetinib, encorafenib, sonidegib, BGJ398, ceritinib, or ribociclib) in patients with solid or hematologic malignancies and an actionable mutation. The primary endpoint of each study was the clinical benefit rate (ie, complete or partial response, or stable disease) at 16 weeks. A total of 192 individual sites were opened in the United States, with a median start-up time of 3.6 weeks. The most common tumor types among the 595 treated patients were colorectal (9.2%), non-small cell lung adenocarcinoma (9.1%), and ovarian (8.4%). Frequent genetic alterations were in PIK3CA, RAS, p16, and PTEN. Overall, 30 partial or complete responses were observed with 6 compounds in 16 tumor types. The Signature Program presents a unique and successful approach for rapid signal finding across multiple tumors and allowed various agents to be evaluated in patients with rare alterations. Incorporating these program features in conventional studies could lead to improved trial efficiencies and patient outcomes.

Purpose: Genomic profiling of tumor biopsies from advanced gastrointestinal and anal cancers is increasingly used to inform treatment. In some cases, tissue biopsy can be prohibitive, and we sought to investigate whether analysis of blood-derived circulating tumor DNA (ctDNA) may provide a minimally invasive alternative. Experimental Design: Hybrid capture–based genomic profiling of 62 genes was performed on blood-based ctDNA from 417 patients with gastrointestinal carcinomas to assess the presence of genomic alterations (GA) and compare with matched tissue samples. Results: Evidence of ctDNA was detected in 344 of 417 samples (82%), and of these, ≥1 reportable GA was detected in 89% (306/344) of samples. Frequently altered genes were TP53 (72%), KRAS (35%), PIK3CA (14%), BRAF (8%), and EGFR (7%). In temporally matched ctDNA and tissue samples available from 25 patients, 86% of alterations detected in tissue were also detected in ctDNA, including 95% of short variants, but only 50% of amplifications. Conversely, 63% of alterations detected in ctDNA were also detected in matched tissue. Examples demonstrating clinical utility are presented. Conclusions: Genomic profiling of ctDNA detected potentially clinically relevant GAs in a significant subset of patients with gastrointestinal carcinomas. In these tumor types, most alterations detected in matched tissue were also detected in ctDNA, and with the exception of amplifications, ctDNA sequencing routinely detected additional alterations not found in matched tissue, consistent with tumor heterogeneity. These results suggest feasibility and utility of ctDNA testing in advanced gastrointestinal cancers as a complementary approach to tissue testing, and further investigation is warranted. Clin Cancer Res; 24(8); 1881–90. ©2018 AACR.

TPS3144 Background: The extracellular matrix (ECM) plays an important role in solid tumor pathogenesis and is a major focus of research and therapeutic targeting. Integrin beta-6 is a cell surface receptor that interacts with the ECM to mediate cellular adhesion. Integrin beta-6 is overexpressed in numerous solid tumors and its expression is a negative prognostic marker in cancers including colorectal, non-small cell lung, gastric, and cervical cancers. SGN-B6A is an investigational vedotin, an antibody-drug conjugate directed against integrin beta-6 to selectively deliver the cytotoxic agent monomethyl auristatin E, which binds tubulin and induces apoptosis. In multiple xenograft models, treatment with SGN-B6A resulted in tumor growth delay and regression in tumor volume when compared to non-binding control. Methods: SGNB6A-001 (NCT04389632) is a phase 1, first-in-human, open-label, multicenter study designed to evaluate the safety, tolerability, pharmacokinetics (PK), and antitumor activity of SGN-B6A in adults with select advanced solid tumors. Primary objectives are to evaluate the safety and tolerability of SGN-B6A in patients with advanced solid tumors, identify the maximum tolerated dose, and identify a recommended dose and schedule. The study has 2 parts: dose escalation (Part A) and dose expansion with multiple disease-specific cohorts and a biology cohort (Part B). SGN-B6A will initially be given by intravenous infusion on Days 1, 8, and 15 of 21-day cycles. The dose escalation (Part A) will be conducted using the modified toxicity probability interval method to determine a dose that demonstrates a dose-limiting toxicity rate of 25% with a 5% margin. The dose and schedule for Part B will be determined based on evaluation of safety, PK, and pharmacodynamic biomarkers. Response evaluations will be based on RECIST v1.1. Patients must be ≥18 years old and have histologically or cytologically confirmed metastatic or unresectable solid malignancy within one of the following tumor types: non-small cell lung cancer, head and neck squamous cell cancer, breast cancer, esophageal cancer, ovarian cancer, cutaneous squamous cell cancer, exocrine pancreatic adenocarcinoma, bladder cancer, cervical cancer, or gastric cancer. After an appropriate dose and schedule are determined in Part A, safety and preliminary antitumor efficacy of SGN-B6A will be evaluated in indication-specific cohorts (Part B). This study is ongoing in sites across North America and Europe. Clinical trial information: NCT04389632.

3523 Background: Small bowel adenocarcinoma (SBA) is a rare malignancy, with lower incidence, later stage at diagnosis, and worse overall survival compared to other intestinal cancers, such as colorectal cancer (CRC). Since the majority of small bowel tumors are not accessible to endoscopic biopsy, comprehensive genomic profiling using circulating tumor DNA (ctDNA) may enable non-invasive detection of targetable genomic alterations (GA) in SBA patients. In this study, we characterize the ctDNA GA landscape in SBA. Methods: Analysis of 299 ctDNA samples prospectively collected from 265 SBA patients between 2017 to 2020 was performed using a 73 gene next generation sequencing panel (Guardant360). A subset of patients underwent longitudinal analysis of changes in GA associated with systemic therapy. Results: Of the 265 patients, 160 (60.3%) were male; the median age was 66 (range: 21-93 years). The most common GA identified in SBA patients included TP53 [58%], KRAS [44%], and APC [40%]. MSI was detected in 3.4% of SBA patients. When stratified by primary tumor location, APC, KRAS, TP53, PIK3CA, and ARID1A were the most common GA identified in both duodenal and jejunal adenocarcinomas. ERBB2, BRCA2 and CDK6 alterations were enriched in duodenal adenocarcinoma, while NOTCH and BRAF alterations were enriched in jejunal adenocarcinoma. The most common currently-targetable GA identified were ATM [18%], PIK3CA [17%], EGFR [15%], CDK4/6 [11%], BRAF [10%], and ERBB2 [10%]. Unique differences in GA between SBA and CRC were identified: i) the majority of ERBB2 alterations are mutations (89%) in the extracellular domain and kinase domain, not amplifications (11%); ii) the majority of BRAF alterations are non V600E mutations (69%) and amplifications (28%); iii) there is a significantly lower rate of APC mutations (40%). Alterations in DNA damage response pathway proteins, including ATM and BRCA 1/2, were identified in 30% of SBA patients. ATM alterations were more common in patients ³65 years old. The most common mutations predicted to be related to clonal hematopoiesis of indeterminate potential were TP53, KRAS and GNAS. Longitudinal ctDNA analysis in 4 SBA patients revealed loss of mutations associated with therapeutic response (TP53 R342*, MAPK3 R189Q) and acquired mutations associated with therapeutic resistance (NF1 R1968*, MET S170N, RAF1 L613V). Conclusions: This study represents the first large-scale blood-based ctDNA genomic profiling of SBA. SBA represents a unique molecular entity with differences in frequency and types of GA compared to CRC. Variations in GA were noted based on anatomic origin within the small intestine. Longitudinal ctDNA monitoring revealed novel GA associated with therapeutic resistance. Identification of multiple targetable GA may facilitate clinical decision making and improve patient outcomes in SBA, especially when a tissue biopsy is not feasible or sufficient for comprehensive genomic profiling.

5509 Background: The accelerated FDA approval of pembrolizumab validated the efficacy of anti–PD-(L)1 therapy for pts with recurrent/metastatic cervical cancer; however, the objective response rate (ORR) with pembrolizumab was 14.3% in pts with PD-L1 expressing tumors. HPV infection is implicated in > 95% of cervical cancers and is linked to upregulation of TGF-β signaling. Bintrafusp alfa is a first-in-class bifunctional fusion protein composed of the extracellular domain of the TGF-βRII receptor (a TGF-β “trap”) fused to a human IgG1 mAb blocking PD-L1. We report pooled safety and efficacy in pts with immune checkpoint inhibitor–naive, recurrent/metastatic cervical cancer treated with bintrafusp alfa in phase 1 (INTR@PID 001; NCT02517398) and phase 2 (study 012; NCT03427411) studies. Methods: Pts with pretreated, immune checkpoint inhibitor–naive, recurrent/metastatic cervical cancer received bintrafusp alfa 0.3-30 mg/kg (phase 1 dose escalation) or 1200 mg Q2W (phase 1 expansion/phase 2) until progressive disease, unacceptable toxicity, or withdrawal. Treatment past progression was allowed. Primary endpoints were safety for the dose-escalation part of the phase 1 study and best overall response per RECIST 1.1 for the expansion part of phase 1 and phase 2 studies. Secondary endpoints for the expansion part of the phase 1 and 2 studies included safety. Results: As of May 15, 2020 (phase 1) and December 22, 2020 (phase 2), 39 pts had received bintrafusp alfa for a median duration of 2.8 months (range, 0.5-19.3). The median follow-up to data cutoff was 35.0 months and 24.1 months for the phase 1 and phase 2 studies, respectively. All pts had received prior anticancer therapy; 16 pts (41.0%) had received ≥3 prior anticancer regimens. There were 2 complete responses and 9 partial responses (PRs; ORR per RECIST 1.1, 28.2%). Median duration of response was 11.7 months (range, 1.4-41.2), and 5 pts (45.5%) had ongoing responses (duration 1.5-41.2 months). An additional delayed PR was observed (duration 23.7 months). Reponses occurred irrespective of tumor histology or prior bevacizumab or radiation treatment. Median overall survival (mOS) was 13.4 months (95% CI, 5.5 to not reached); 24-month OS rate was 33.2%. Any-grade treatment-related adverse events (TRAEs) occurred in 33 pts (84.6%). Grade 3 TRAEs occurred in 8 pts (20.5%; anemia, colitis, gastroparesis, upper gastrointestinal hemorrhage, keratoacanthoma, cystitis noninfective, hematuria, pneumonitis, rash macular [n = 1 each]); 1 patient (2.6%) had a grade 4 TRAE (asymptomatic hypokalemia related to the above grade 3 gastroparesis). No treatment-related deaths occurred. Conclusions: Bintrafusp alfa had a manageable safety profile and demonstrated clinical activity in pts with heavily pretreated, immune checkpoint inhibitor–naive recurrent/metastatic cervical cancer. Clinical trial information: NCT02517398 , NCT03427411.

5550 Background: STRO-002-GM1 is a Phase 1, open-label study in patients (pts) with advanced, platinum resistant or refractory EOC. STRO-002 is a novel FRα-targeting ADC with a precise DAR of 4 using site-specific conjugation technology to circumvent limitations of current ADCs. STRO-002 induces immunogenic cell death and contains the tubulin-targeting 3-aminophenyl hemiasterlin warhead SC209, a potent cytotoxin that is a weak substrate for P-gp. Methods: STRO-002 is given IV on Day 1 of each 21-day cycle until disease progression. Ocular exams are performed at baseline and every other cycle. Prophylactic corticosteroid eyedrops are not administered. FRα expression was not required for eligibility and retrospective analysis of FRα expression in archival tumor tissue is ongoing. Results: Enrollment has been completed with 39 pts treated at 9 dose levels (0.5 to 6.4 mg/kg). Data cut-off is Jan 30, 2021. Median age was 61 years (range 48-79). Median number of prior systemic therapies was 6 (range 2-11). 86% of treatment emergent adverse events (AEs) were Grade 1-2. The most common treatment related Grade 3 and 4 AEs were reversible neutrophil count decreased (36%) and neutropenia (33%), Grade 3 arthralgia (12.8%) and neuropathy (7.7%). Two pts developed neutropenic fever that resolved with antibiotic therapy. 34 pts were treated at clinically active doses (≥ 2.9 mg/kg) and 31/34 are evaluable for RECIST 1.1 response. Objective responses were seen in 10/31 pts - 1 CR, 4 confirmed PR, and 5 unconfirmed PR (imaging studies under review in 1 pt with uPR). Disease control rate (CR+PR+SD) is 74% at ≥ 12 weeks and 61% at ≥ 16 weeks. 5 pts remain on treatment with 3 ongoing at > 74 weeks. FRα-expression results are available in 14 pts treated at ≥ 2.9 mg/kg with 50% low, 21% medium and 29% high FRα-expressing tumors per PS2+ scoring algorithm. 12/13 pts with H-scores of ≥ 105 achieved disease control with PR or SD. Maximum plasma concentrations of STRO-002 were achieved at the end of the 1 hour infusion and exposure increased in an apparent dose proportionate/linear manner. Conclusions: STRO-002 is a novel FRα-targeting ADC with an encouraging emerging safety and efficacy profile in heavily pretreated relapsed/refractory EOC. No ocular toxicity signals have been observed. Durable responses and anti-tumor activity have been demonstrated across a broad range of FRα expression levels in evaluable pts treated at ≥ 2.9 mg/kg. 48% (15/31) of pts were on treatment without disease progression for ≥ 24 weeks and 13% (4/31) remain on treatment for over a year, suggesting that STRO-002 is well tolerated in long-term responding patients. A randomized expansion cohort comparing STRO-002 at 4.3 mg/kg vs 5.2 mg/kg dose levels in less heavily pretreated EOC pts is ongoing. Clinical trial information: NCT03748186.

ALK rearrangements have been observed in 0.05%-2.5% of patients with colorectal cancers (CRCs) and are predicted to be oncogenic drivers largely mutually exclusive of KRAS, NRAS, or BRAF alterations. Here we present the case of a patient with metastatic CRC who was treatment naive at the time of molecular testing. Initial ALK immunohistochemistry (IHC) staining was negative, but parallel genomic profiling of both circulating tumor DNA (ctDNA) and tissue using similar hybrid capture-based assays each identified an identical STRN-ALK fusion. Subsequent ALK IHC staining of the same specimens was positive, suggesting that the initial result was a false negative. This report is the first instance of an ALK fusion in CRC detected using a ctDNA assay. Key points Current guidelines for colorectal cancer (CRC) only recommend genomic assessment of KRAS, NRAS, BRAF, and microsatellite instability (MSI) status.ALK rearrangements are rare in CRC, but patients with activating ALK fusions have responded to targeted therapiesALK rearrangements can be detected by genomic profiling of ctDNA from blood or tissue, and this methodology may be informative in cases where immunohistochemistry (IHC) or other standard testing is negative.

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 >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., >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.

Background Onartuzumab is a monovalent monoclonal antibody that binds with the extracellular domain of the MET receptor. Given the role of MET in non–small-cell lung cancer (NSCLC), we investigated whether onartuzumab added to first-line chemotherapy efficacy in non-squamous NSCLC. Methods Patients with untreated stage IIIB/IV non-squamous NSCLC, stratified by MET diagnostic status, were randomized to receive onartuzumab (15 mg/kg intravenously every 3 weeks) or placebo in combination with either paclitaxel/platinum/bevacizumab (bevacizumab cohort), or in combination with platinum/pemetrexed (pemetrexed cohort) with maintenance bevacizumab or pemetrexed and onartuzumab/placebo as appropriate. Co-primary endpoints of this phase II study were progression-free survival (PFS) in all patients and in MET+ patients (2+/3+), defined by the Ventana immunohistochemistry assay; secondary endpoints included overall survival (OS), objective response rate (ORR), safety, and pharmacokinetics. Results Efficacy data were available for 139 and 120 patients in the bevacizumab and pemetrexed cohorts, respectively. No benefit was seen in the PFS endpoint in the intent-to treat population of either cohort, but was numerically worse in the onartuzumab arm of the MET+ subgroup of the bevacizumab cohort. The onartuzumab and placebo arms had similar ORR and OS results in both cohorts. A higher incidence of some adverse events was observed with onartuzumab versus placebo, including peripheral edema (30% vs. 3%, bevacizumab cohort; 48% vs. 14%, pemetrexed cohort) and venous thromboembolic events (bevacizumab cohort only, 15% vs. 6%). Conclusion Onartuzumab does not appear to provide any additional clinical benefit when given in combination with current first-line standard-of-care chemotherapy for non-squamous NSCLC.

Background FGFR2 gene aberrations (GA) include fusions and mutations/amplifications, with an estimated prevalence of approximately 15% and 5% in iCCA, respectively. While FGFR2 fusions are acknowledged oncogenic drivers, the oncogenic potential of FGFR2 mutations and amplifications is less well defined, due to ambiguous available preclinical and clinical data. In a non-comparative Phase 2a study (NCT01752920), the potent pan-FGFR inhibitor DZB was administered to iCCA pts expressing either FGFR2-fusion (N=29), FGFR2 mutations/amplifications (N=6) or no FGFR gene aberration (N=9). Here, we present a post-hoc analysis of outcomes of iCCA pts expressing FGFR mutations/amplifications (N=6) or no FGFR GA (N=9) as compared to previously reported data of iCCA pts (N=29) expressing FGFR2 fusions (Mazzaferro et al. 2018 BJC). Methods Pts received 300mg DZB QD PO. Eligibility criteria included a locally confirmed (FISH or NGS) testing of FGFR2 GA (fusions vs mutations/amplifications or no aberrations). Objective responses were determined per RECIST 1.1. Disease control rate (DCR) was defined by the summation of CR, PR and SD, and PFS, calculated from treatment initiation until disease progression or death. Results The table shows the efficacy outcomes in the 3 patient groups. Types of drug-related adverse events were similar across groups. No new safety signals were identified.Table721PTableiCCA patient groupFGFR2 fusion N=29FGFR2 mutation/ amplification N=6No FGFR2 genomic aberration N=9Objective response rate (RECIST 1.1)6 (21%)0 (0%)0 (0%)DCR (PR or SD)24 (83%)4 (67%)2 (22%)Any target lesion diameter reduction18 (62%)4 (67%)0 (0%)Median (95% CI) Progression free survival (PFS), months5.76.71.5(4.0-9.2)(1.0-14.7)(0.7 – NA)% PFS at 3 months83%67%0%% PFS at 6 months47%50%0% Conclusions Anti-tumor efficacy of DZB as measured by DCR and PFS in iCCA patients harboring an FGFR2 GA seems to be similar for patients with FGFR2 fusions and FGFR2 mutations/amplifications, while patients without any detectable FGFR GA appear to derive no benefit from DZB treatment. While the influence of prognostic variables still has to be confirmed, the anti-tumor efficacy of DZB seen in pts with FGFR2 GA other than fusions warrant further clinical investigation. Legal entity responsible for the study Basilea Pharmaceutica International Ltd. Funding Basilea Pharmaceutica International Ltd. Disclosure S. Braun: Full / Part-time employment: Basilea Pharmaceutica Int. Ltd.; Shareholder / Stockholder / Stock options: Ipsen. B. El-Rayes: Advisory / Consultancy: Merrimack; Advisory / Consultancy: BTG; Honoraria (self), Advisory / Consultancy: Bayer; Advisory / Consultancy: Loxo; Honoraria (self), Advisory / Consultancy: RTI Health Solutions; Honoraria (self), Speaker Bureau / Expert testimony: Lexicon; Speaker Bureau / Expert testimony, Research grant / Funding (institution): Bristol-Myers Squibb; Research grant / Funding (institution): Taiho Pharmaceutical; Research grant / Funding (institution): Boston Biomedical; Research grant / Funding (institution): Cleave Biosciences; Research grant / Funding (institution): Genentech; Research grant / Funding (institution): AVEO; Research grant / Funding (institution): Pfizer; Research grant / Funding (institution): Novartis; Research grant / Funding (institution): Hoosier Cancer Research Network; Research grant / Funding (institution): Five Prime Therapeutics; Research grant / Funding (institution): PPD; Research grant / Funding (institution): Merck; Research grant / Funding (institution): ICON Clinical Research. W.P. Harris: Advisory / Consultancy: Neo Therma; Advisory / Consultancy, Research grant / Funding (institution): Bayer; Advisory / Consultancy, Research grant / Funding (institution), Travel / Accommodation / Expenses: Eisai; Advisory / Consultancy, Research grant / Funding (institution): Exelixis; Advisory / Consultancy, Research grant / Funding (institution): Bristol-Myers Squibb; Research grant / Funding (institution): ArQule; Research grant / Funding (institution): Halozyme; Research grant / Funding (institution): Nordion; Research grant / Funding (institution): MedImmune; Research grant / Funding (institution): Agios. N. Damjanov: Advisory / Consultancy: Bayer; Advisory / Consultancy: Amgen; Advisory / Consultancy: Celgene; Honoraria (self): Sirtex Medical. L. Rimassa: Advisory / Consultancy: Bayer; Advisory / Consultancy: Sirtex Medical; Advisory / Consultancy: Italfarmaco; Advisory / Consultancy: Sanofi; Advisory / Consultancy, Travel / Accommodation / Expenses: ArQule; Advisory / Consultancy: Baxter; Advisory / Consultancy, Travel / Accommodation / Expenses: Ipsen; Advisory / Consultancy: Exelixis; Advisory / Consultancy: Amgen; Advisory / Consultancy: Incyte; Advisory / Consultancy: Celgene; Advisory / Consultancy: Eisai; Advisory / Consultancy: Lilly; Honoraria (self): AstraZeneca; Honoraria (self): AbbVie; Honoraria (self): Gilead Sciences; Honoraria (self): Roche. F. Braiteh: Honoraria (self), Advisory / Consultancy, Speaker Bureau / Expert testimony, Travel / Accommodation / Expenses: Amgen; Honoraria (self), Advisory / Consultancy, Speaker Bureau / Expert testimony, Travel / Accommodation / Expenses, Shareholder / Stockholder / Stock options: Bristol-Myers Squibb; Advisory / Consultancy, Travel / Accommodation / Expenses, Shareholder / Stockholder / Stock options: Clovis Oncology; Shareholder / Stockholder / Stock options: Agios; Honoraria (self), Advisory / Consultancy, Speaker Bureau / Expert testimony, Travel / Accommodation / Expenses: Ipsen; Honoraria (self), Advisory / Consultancy, Speaker Bureau / Expert testimony, Travel / Accommodation / Expenses, Shareholder / Stockholder / Stock options: Insys Therapeutics; Travel / Accommodation / Expenses, Shareholder / Stockholder / Stock options: Tesaro; Honoraria (self), Advisory / Consultancy, Speaker Bureau / Expert testimony, Travel / Accommodation / Expenses: Genentech/Roche; Honoraria (self), Advisory / Consultancy, Speaker Bureau / Expert testimony: Lilly; Advisory / Consultancy, Speaker Bureau / Expert testimony, Travel / Accommodation / Expenses: Incyte; Honoraria (self), Advisory / Consultancy, Travel / Accommodation / Expenses: Bayer; Advisory / Consultancy, Travel / Accommodation / Expenses: Sanofi; Advisory / Consultancy, Travel / Accommodation / Expenses: Regeneron; Honoraria (self), Advisory / Consultancy, Speaker Bureau / Expert testimony, Travel / Accommodation / Expenses: AstraZeneca; Advisory / Consultancy, Speaker Bureau / Expert testimony: Merck; Honoraria (self), Advisory / Consultancy, Speaker Bureau / Expert testimony, Travel / Accommodation / Expenses: Celgene; Honoraria (self), Advisory / Consultancy, Travel / Accommodation / Expenses: Lexicon; Advisory / Consultancy, Speaker Bureau / Expert testimony, Travel / Accommodation / Expenses: Pfizer; Travel / Accommodation / Expenses: Novartis; Honoraria (self), Advisory / Consultancy, Speaker Bureau / Expert testimony, Travel / Accommodation / Expenses: Boehringer Ingelheim; Honoraria (self), Speaker Bureau / Expert testimony, Travel / Accommodation / Expenses: Taiho Pharmaceutical; Travel / Accommodation / Expenses: Heron. S. Lonardi: Advisory / Consultancy, Research grant / Funding (self): Amgen; Advisory / Consultancy, Speaker Bureau / Expert testimony, Research grant / Funding (self): Merck Serono; Advisory / Consultancy, Speaker Bureau / Expert testimony: Lilly; Speaker Bureau / Expert testimony: Roche; Speaker Bureau / Expert testimony: Bristol-Myers Squibb; Speaker Bureau / Expert testimony: Servier. M. Engelhardt: Full / Part-time employment: Basilea Pharmaceutica Int. Ltd. M. Saulay: Full / Part-time employment: Basilea Pharmaceutica Int. Ltd. B. Schwartz: Leadership role, Shareholder / Stockholder / Stock options, Full / Part-time employment: ArQule; Advisory / Consultancy: CIRM. W.L. Shaib: Research grant / Funding (institution): ArQule; Research grant / Funding (institution): Lilly. V. Mazzaferro: Advisory / Consultancy: Terumo Europe NV; Speaker Bureau / Expert testimony: Ipsen AB. K.P. Papadopoulos: Advisory / Consultancy: Bayer; Advisory / Consultancy, Research grant / Funding (institution): ArQule; Research grant / Funding (institution): AbbVie; Research grant / Funding (institution): MedImmune; Research grant / Funding (institution): Daiichi Sankyo; Research grant / Funding (institution): Regeneron; Research grant / Funding (institution): Sanofi; Research grant / Funding (institution): ARMO BioSciences; Research grant / Funding (institution): Amgen; Research grant / Funding (institution): Calithera Biosciences; Research grant / Funding (institution): Curegenix; Research grant / Funding (institution): Incyte; Research grant / Funding (institution): Merck; Research grant / Funding (institution): Peloton Therapeutics; Research grant / Funding (institution): ADC Therapeutics; Research grant / Funding (institution): 3D Medicines; Research grant / Funding (institution): Formation Biologics; Research grant / Funding (institution): EMD Serono; Research grant / Funding (institution): Syros Pharmaceuticals; Research grant / Funding (institution): Mersana; Research grant / Funding (institution): OncoMed. All other authors have declared no conflicts of interest.

Objective Patients with advanced/recurrent epithelial ovarian and uterine cancers have limited treatment options beyond platinum chemotherapy. Both tumor types can express programmed death-ligand 1 (PD-L1), providing a potential therapeutic target for these patients. Here we present data from the ovarian and uterine cancer cohorts of the Phase I atezolizumab monotherapy study (PCD4989g). Methods This Phase I, multi-center, first-in-human, open-label, dose-escalation/expansion clinical trial investigated single-agent atezolizumab in cohorts of patients with recurrent epithelial ovarian or uterine cancer. The primary objective was to evaluate the safety and tolerability of single-agent atezolizumab. Anti-tumor activity and preliminary assessment of potential biomarkers were evaluated as secondary and exploratory objectives, respectively. Results The ovarian and uterine cancer cohorts enrolled 12 and 15 patients, respectively (10 [83%] and 5 [33%], respectively, had PD-L1 ≥ 5% on tumor-infiltrating immune cells). Atezolizumab was generally well tolerated with no new safety signals identified. The safety profiles in both cohorts were consistent with the known profile of atezolizumab monotherapy. Treatment-related adverse events (AEs) were mostly Grade ≤ 2, with no treatment-related Grade ≥ 4 AEs reported. Preliminary anti-tumor activity, with long durations of response, was observed in 2 patients from each cohort (ovarian cancer, 8.1 and 30.6+ months; uterine cancer, 7.3 and 16.6+ months). High microsatellite instability and tumor mutational burden were noted in the responders from the uterine cancer cohort. Conclusions Atezolizumab monotherapy was well tolerated in patients with epithelial ovarian or uterine cancer and may have clinical activity warranting further investigation. Trial registration ClinicalTrials.gov identifier: NCT01375842

Background Next-generation sequencing has identified actionable genetic aberrations in intrahepatic cholangiocarcinomas (iCCA), including the fibroblast growth factor receptor 2 (FGFR2) fusions. Derazantinib (ARQ 087), an orally bioavailable, multi-kinase inhibitor with potent pan-FGFR activity, has shown preliminary therapeutic activity against FGFR2 fusion-positive iCCA. Methods This multicentre, phase 1/2, open-label study enrolled adult patients with unresectable iCCA with FGFR2 fusion, who progressed, were intolerant or not eligible to first-line chemotherapy (NCT01752920). Subjects received derazantinib in continuous daily doses. Tumour response was assessed according to RECIST 1.1 every 8 weeks. Results Twenty-nine patients (18 women/11 men; median age, 58.7 years), 2 treatment-naive and 27 who progressed after at least one prior systemic therapy, were enrolled. Overall response rate was 20.7%, disease control rate was 82.8%. Estimated median progression-free survival was 5.7 months (95% CI: 4.04–9.2 months). Treatment-related adverse events (AE) were observed in 27 patients (93.1%, all grades), including asthenia/fatigue (69.0%), eye toxicity (41.4%), and hyperphosphatemia (75.9%). Grade ≥ 3 AEs occurred in 8 patients (27.6%). Conclusion Derazantinib demonstrated encouraging anti-tumour activity and a manageable safety profile in patients with advanced, unresectable iCCA with FGFR2 fusion who progressed after chemotherapy. A pivotal trial of derazantinib in iCCA is ongoing (NCT03230318).

The objective of this phase II study was to evaluate the potential of pharmacokinetic (PK) drug–drug interactions between ramucirumab and irinotecan or its metabolite, SN-38, when administered with folinic acid and 5-fluorouracil (FOLFIRI). Patients received intravenous infusions of FOLFIRI and ramucirumab 8 mg/kg on Day 1 of a 2-week cycle. FOLFIRI was administered alone in Cycle 1; ramucirumab followed by FOLFIRI was administered in all subsequent cycles. Blood was collected at regular intervals after infusions in Cycles 1 and 2 to determine irinotecan, SN-38, and ramucirumab concentrations. PK parameters were derived by noncompartmental analysis. Twenty-nine patients received treatment. The dose-normalized area under the concentration versus time curve from zero to infinity [AUC(0–∞)] and the maximum observed concentration (C max) of irinotecan and SN-38 were comparable between Cycle 1 (FOLFIRI alone) and Cycle 2 (ramucirumab + FOLFIRI). The ratios of geometric least squares (LS) means for irinotecan were 0.93 (90 % CI 0.83–1.05) for AUC(0–∞) and 1.04 (90 % CI 0.97–1.12) for C max. The ratios of geometric LS means for SN-38 were 0.95 (90 % CI 0.88–1.04) for AUC(0–∞) and 0.97 (90 % CI 0.85–1.12) for C max. The most common treatment-emergent adverse events, regardless of grade, were fatigue (19 patients, 65.5 %), diarrhea, (16 patients, 55.2 %), and neutropenia (15 patients, 51.7 %). Grade ≥3 neutropenia was reported in 7 (24.1 %) patients. There was no PK drug–drug interaction between ramucirumab and irinotecan or its metabolite, SN-38. Ramucirumab with FOLFIRI was well tolerated in this study, with no new safety concerns.

Background: The release of ATP from dying cancer cells in response to platinum-based chemotherapy increases extracellular immunosuppressive adenosine (A), which binds to and activates the A2a and A2b receptors on immune cells resulting in an ineffective anti-tumor immune response. Concomitant adenosine receptor blockade may therefore enhance the therapeutic efficacy of some chemotherapeutic agents. AB928, the first clinical-stage small molecule dual adenosine receptor antagonist, is highly potent, pharmacodynamically active, and has been well tolerated in dose escalation studies as a single agent or in combination with chemo/immunotherapy. Methods: ARC-3 (NCT03720678) is a Phase 1/1b, open-label study in participants (pts) with advanced CRC. Phase 1 escalation identified AB928 150 mg orally once daily as the recommended dose in combination with standard mFOLFOX-6. Phase 1b expansion is ongoing and includes at least 15 and up to 40 pts. Eligible pts must have unresectable or mCRC, ECOG performance status 0-1, and at least one RECIST measurable lesion. Phase 1 eligibility included up to 5 lines of prior therapy; Phase 1b is similarly scoped. Exploratory biomarker analyses include immunohistochemistry of the adenosine axis, tumoral next gene sequencing, and tumor/blood immune correlates. Results: As of 27Dec19, 21 pts received AB928 150 mg + mFOLFOX-6: 7 in Phase 1 and 14 in Phase 1b. All previously treated pts (n=12) were FOLFOX- and/or FOLFIRI-experienced. Prior metastatic therapies range from 3 to 5 in Phase 1 escalation and 0 to 3 in Phase 1b expansion. Adverse events (AEs) reported in >30% of pts included fatigue, diarrhea, and thrombocytopenia. AEs related to AB928 occurred in 13 pts and were mostly mild to moderate. AB928-related Grade 3 AEs reported by 3 pts were diarrhea, AST increase, and neutropenia; there were no Grade 4-5 AB928-related AEs. Out of 15 evaluable pts, by investigator assessment, the disease control rate was 100% with 2 partial responses (13%; 1 confirmed, 1 pending confirmation) and 13 stable disease (87%). Of pts with stable disease, 6/13 (46%) had tumor shrinkage >15%. Median time on treatment was 15.4 (range: 1.7 - 40.6+) and 11.9 (range: 2.7 - 15.7+) weeks for Phase 1 and Phase 1b, respectively, with initiation of Phase 1b dosing on 09Sep19. Enrollment up to 40 pts is proceeding based on early efficacy gates; 15 pts are currently receiving study treatment. Conclusions: AB928 with mFOLFOX-6 has been well tolerated without significant evidence of additive toxicity in pts with mCRC. Combination treatment was associated with disease control in all evaluable pts, including those with microsatellite stable and RAS/BRAF mutated mCRC. Additional updates on the safety, clinical activity, and correlative biomarker results for all escalation/expansion pts will be presented. Citation Format: Michael Cecchini, Manuel Modiano, Fadi Braiteh, Olivia S. Gardner, Houston N. Gilbert, Daniel DiRenzo, Lisa Seitz, Matt J. Walters, Fangfang Yin, Rachel Woloski, Melissa C. Paoloni, Ki Y. Chung. Efficacy and safety of AB928 plus modified FOLFOX-6 (mFOLFOX-6) in participants with metastatic colorectal cancer (mCRC): Initial results at the recommended dose for expansion (ARC-3) [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr LB-387.

Introduction: Insulin-like growth factor (IGF) signaling and the cyclin D-cyclin-dependent kinase (CDK) 4 & 6-retinoblastoma pathway are implicated in cancer progression and treatment resistance. Activation of the IGF receptor results in upregulation of cyclin D1 and progression through the cell cycle. Dual inhibition of IGF and CDK 4 & 6 should lead to decreased cell proliferation through disruption of cell-cycle progression. This phase Ib trial assessed safety and preliminary efficacy of xentuzumab, an IGF-ligand neutralizing antibody, in combination with abemaciclib, a CDK 4 & 6 inhibitor. In a dose-finding cohort in patients (pts) with solid tumors, the recommended phase II dose was determined as xentuzumab 1000 mg weekly intravenously plus abemaciclib 150 mg every 12 hours (Q12h) orally. Here, we present data from an expansion cohort in pts with NSCLC. Methods: Eligible pts had stage IV NSCLC with measurable disease which had progressed after platinum-based chemotherapy and immunotherapy, and had either received 1-2 prior chemotherapies for advanced/metastatic disease or were judged ineligible for further standard second-line chemotherapy. Prior CDK 4 & 6 inhibitor therapy was not permitted. Pts received xentuzumab 1000 mg weekly plus abemaciclib 150 mg Q12h until disease progression or intolerability of study medication. The primary endpoint was objective response defined as best overall response of complete response or partial response (PR) per RECIST 1.1. Secondary endpoints included progression-free survival (PFS). Results: 25 pts with NSCLC were treated (17 male [68%], median age 64 years [range 53-76]). 4 pts remained on treatment at time of analysis. Median treatment exposure was 1.6 months (range 0.5-19.7). Of 19 pts evaluable for response, 1 had a best overall response of PR (65% target lesion shrinkage), 9 had stable disease (duration ≥24 weeks in 3 pts) and 9 had progressive disease. Median PFS was 2.1 months (95% CI 1.2-5.3). All pts experienced adverse events (AEs) and 23 experienced treatment-related AEs (TRAEs), most commonly diarrhea (n=15; 60%), nausea (n=10; 40%) and platelet count decreased (n=8; 32%). The most common grade ≥3 TRAEs were thrombocytopenia (n=4; 16%) and neutropenia (n=3; 12%). No AEs of hyperglycemia or blood glucose increased were reported. Serious AEs were experienced by 13 pts (52%). 2 pts had fatal serious AEs due to disease progression and respiratory failure. Conclusion: The combination of xentuzumab and abemaciclib showed preliminary efficacy in pts with NSCLC who had progressed on chemotherapy and an immune checkpoint inhibitor. One PR was reported. The combination had a manageable safety profile. Citation Format: Patricia LoRusso, Javier García-Corbacho, Fadi S. Braiteh, Anthony Gonçalves, Francesco Ricci, Hiroji Iwata, Marta Capelán, Marie Paule Sablin, Aleix Prat, Molly Catherine Hardebeck, Marta Puig, Dennis Chin-Lun Huang, Mingchi Hsu, Douglas Yee. An open label, multi-cohort, phase Ib study of xentuzumab and abemaciclib: Preliminary results from the advanced non-small cell lung cancer (NSCLC) cohort [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr CT165.

Background: Neoantigens arising from somatic mutations are attractive targets for cancer immunotherapy as they may be recognized as foreign by the immune system. RO7198457 is a systemically administered RNA-Lipoplex iNeST designed to stimulate T cell responses against neoantigens. A first-in-human Phase Ia study of RO7198457 was conducted in patients with locally advanced or metastatic solid tumors. Methods: RO7198457 is manufactured on a per-patient basis and contains up to 20 patient- specific neoantigens. Nine doses of RO7198457 were administered i.v. at weekly and bi-weekly intervals during the 12-week induction stage and every 24 weeks during the maintenance stage. Results: In total, 29 patients enrolled in cohorts with doses ranging from 25-100 μg. The most common tumor types were HR+/HER2+ breast, prostate, and ovarian cancer. The median number of prior therapies was 5 (range 1-17). 34% of patients received prior immunotherapy. Most patients had low PD-L1 expression (97% patients with Conclusion: RO7198457 can be manufactured for individual patients with clinically relevant turn-around times. RO7198457 has a manageable safety profile consistent with its mechanism of action, and induced strong neoantigen-specific immune responses in patients with low and intermediate mutational load tumors types. A Ph1b study in combination with atezolizumab and a randomized Ph2 study of RO7198457 in 1L melanoma patients with pembrolizumab have been initiated, and two randomized clinical trials are planned in resected lung and CRC. Citation Format: Fadi Braiteh, Patricia LoRusso, Ani Balmanoukian, Sam Klempner, D R. Camidge, Matthew Hellmann, Michael Gordon, Johanna Bendell, Lars Mueller, Rachel Sabado, Patrick Twomey, Leila Delamarre, Jack Huang, Mahesh Yadav, Jingbin Zhang, Patrick McDonald, Felicitas Müller, Evelyna Derhovanessian, Özlem Türeci, Ugur Sahin, Lillian Siu. A phase Ia study to evaluate RO7198457, an individualized Neoantigen Specific immunoTherapy (iNeST), in patients with locally advanced or metastatic solid tumors [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr CT169.

Background: Neoantigens arising from somatic mutations are attractive targets for cancer immunotherapy as they may be recognized as foreign by the immune system. RO7198457, a systemically administered RNA-Lipoplex iNeST was designed to stimulate T cell responses against neoantigens. A first-in-human Phase Ib study of RO7198457, in combination with the aPD-L1 antibody atezolizumab is being conducted in patients with locally advanced or metastatic solid tumors. Methods: RO7198457 is manufactured on a per-patient basis and contains up to 20 tumor-specific neoepitopes. Nine doses of RO7198457 were administered i.v. in weekly and bi-weekly intervals during the 12-week induction stage and every 24 weeks during the maintenance stage. Atezolizumab 1200 mg was administered on Day 1 of each 21-day cycle. Results: In total, 132 patients enrolled in cohorts with doses ranging from 15-50 μg RO7198457 in combination with atezolizumab. Most common tumor types were NSCLC, TNBC, melanoma and CRC. The median number of prior therapies was 3 (range 1-11). 39% of patients received prior immunotherapy. Most patients had low levels of PD-L1 expression (93% patients with Citation Format: Juanita S. Lopez, Ross Camidge, Marco Iafolla, Sylvie Rottey, Martin Schuler, Matthew Hellmann, Ani Balmanoukian, Luc Dirix, Michael Gordon, Ryan Sullivan, Brian S. Henick, Charles Drake, Kit Wong, Patricia LoRusso, Patrick Ott, Lawrence Fong, Aglaia Schiza, Jeffery Yachnin, Christian Ottensmeier, Fadi Braiteh, Johanna Bendell, Rom Leidner, George Fisher, Guy Jerusalem, Laura Molenaar-Kuijsten, Marcus Schmidt, Scott A. Laurie, Raid Aljumaily, Achim Rittmeyer, Eelke Gort, Ignacio Melero, Lars Mueller, Rachel Sabado, Patrick Twomey, Jack Huang, Manesh Yadav, Jingbin Zhang, Felicitas Mueller, Evelyna Derhovanessian, Ugur Sahin, Özlem Türeci, Thomas Powles. A phase Ib study to evaluate RO7198457, an individualized Neoantigen Specific immunoTherapy (iNeST), in combination with atezolizumab in patients with locally advanced or metastatic solid tumors [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr CT301.

e16050 Background: The PI3K/mTOR pathway overactivation and loss of PTEN occur in 20-40% of mCRC pts. A recent phase 1/2 study in mCRC pts showed evidence that everolimus added to 1L SOC treatment improved outcomes, in particular in pts with PTEN loss (Gilcrease, 2019). This prospective, single-arm phase 1/2 study aims to identify the optimal dose and schedule of nab-sirolimus (ABI-009), an mTOR inhibitor, plus FB and evaluate the safety and preliminary efficacy of this regimen. Methods: Eligible pts have no prior therapy, ≥18 years old, ECOG performance status of 0-2. PTEN loss (by IHC) is evaluated for all pts. nab-Sirolimus IV starting dose and schedule was 30mg/m2 weekly for 3 weeks followed by a week of rest (on D1, 8, and 15 in a 28-day cycle, qw3/4) plus standard doses of FB on D1 and D15. Dose escalation to 45 and 60mg/m2 or de-escalation to 20 and 10mg/m2 followed the 3+3 design. Dose limiting toxicity (DLT) was assessed in cycle 1. Results: As of Jan 31, 2020, 24 pts were treated in the phase 1 study and 18 were evaluable for response. No DLTs were observed in the first 3 pts treated with nab-sirolimus at 30mg/m2 qw3/4; however, all 3 pts missed D8 doses (due to G2 thrombocytopenia and G3 neutropenia) and the cohort expanded to additional 3 pts for further observation. 5/6 pts missed D8 doses and a new dose cohort enrolled pts at 20mg/m2 qw3/4. No DLTs were observed and the cohort was expanded to 10 pts. A safety review of the first 18 pts observed that 9/18 pts missed doses on D8 and a new cohort was added to enroll pts at 20 mg/m2 q2w (D1 and D15, as for FB). This cohort enrolled 8 pts with no DLTs and represents the recommended-phase-2-dose (RP2D) and continues enrollment in phase 2. For all pts, 15/24 (63%) pts had G3-4 treatment-related adverse events (TRAEs); most common were neutropenia (6/24, 25%) and thrombocytopenia (4/24, 17%). At the RP2D 3/8 (38%) pts had G3-4 TRAEs (thrombocytopenia, weight loss, and hypertension, 1 pt each). Among 18 evaluable pts, best response was: 7/18 (39%) partial response, 10/18 (56%) stable disease, and 16/18 (89%) had tumor shrinkage. PTEN was assessed in 14 pts: 4/14 (29%) had PTEN loss, 2/4 (50%) PTEN loss pts responded, while 3/10 (30%) pts that were PTEN+ (WT) had a response. Conclusions: The RP2D of nab-sirolimus is 20mg/m2 q2w in combination with standard mFOLFOX+bevacizumab. The phase 2 portion of the study is ongoing. Clinical trial information: NCT03439462 .

TPS3647 Background: Nectin-4, a transmembrane cell adhesion protein, is highly expressed in urothelial carcinoma (UC), breast cancer (BC), non-small cell lung cancer (NSCLC), and gastroesophageal cancers (GEC); targeting Nectin-4 on these tumors may provide a novel treatment approach. Enfortumab vedotin (EV), an investigational human monoclonal antibody-drug conjugate, binds to Nectin-4 and upon internalization releases MMAE resulting in cell cycle arrest and cell death. Recently, EV received accelerated approval by the FDA for the treatment of adults with locally advanced/metastatic UC who previously received a PD-1 or PD-L1 inhibitor, and a platinum-containing chemotherapy in the neoadjuvant/adjuvant, locally advanced or metastatic setting. Use of EV in this study is investigational. Methods: This open-label phase 2 study (NCT04225117) will assess the efficacy and safety/tolerability of EV in patients (pts) with previously treated locally advanced/metastatic malignant solid tumors. Adult pts (~240) with histologically or cytologically confirmed disease and an ECOG ≤1 will be enrolled into 1 of 6 tumor-specific cohorts (Table), with ~40 pts each. While Nectin-4 expression is not required for enrollment, it is being tested retrospectively. Patients with active CNS metastases, grade ≥2 preexisting sensory or motor neuropathy, grade ≥3 immunotherapy-related hypothyroidism or panhypopituitarism, ongoing grade >3 immunotherapy-related AEs requiring high-dose steroids, or a history of uncontrolled diabetes mellitus within 3 months of the study will be excluded. All pts will receive EV 1.25 mg/kg IV on Days 1, 8, and 15 of each 28-day cycle until treatment discontinuation criteria are met; dose reductions/interruptions will be permitted. For all cohorts, the primary endpoint is investigator-assessed confirmed objective response rate (RECIST v1.1); secondary endpoints include duration of response, disease control rate, progression-free and overall survival, and safety/tolerability of EV. This study is recruiting as of February 2020. Clinical trial information: NCT04225117 . [Table: see text]