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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.

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: 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 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.

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.

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.

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).

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.

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]

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

This phase II trial examined the addition of ramucirumab, a vascular endothelial growth factor receptor-2 monoclonal antibody, to mFOLFOX6 as front-line therapy for patients with advanced gastric/GEJ or esophageal adenocarcinoma. A survival benefit was not observed in the ITT population, but an exploratory analysis suggested a potential benefit for ramucirumab in the gastric/GEJ cancer subgroup. Background We report the first randomized, Phase II trial of ramucirumab, an anti-vascular endothelial growth factor receptor-2 monoclonal antibody, as front-line therapy in patients with advanced adenocarcinoma of the esophagus or gastric/gastroesophageal junction (GEJ). Patients and methods Patients from the USA with advanced esophageal, gastric, or GEJ adenocarcinoma randomly received (1:1) mFOLFOX6 plus ramucirumab (8 mg/kg) or mFOLFOX6 plus placebo every 2 weeks. The primary end point was progression-free survival (PFS) with 80% power to detect a hazard ratio (HR) of 0.71 (one-sided α = 0.15). Secondary end points included evaluation of response and overall survival (OS); an exploratory ramucirumab exposure–response analysis was undertaken. Results Of 168 randomized patients, 52% of tumors were located in the stomach/GEJ and 48% in the esophagus. The trial did not meet the primary end point of PFS [6.4 versus 6.7 months, HR 0.98 (95% confidence interval 0.69–1.37)] or the secondary end point of OS (11.7 versus 11.5 months) in the intent-to-treat (ITT) population. Objective response rates (45.2% versus 46.4%) were similar between arms. Most Grade ≥3 toxicities did not differ significantly between arms, yet premature discontinuation of FOLFOX and ramucirumab (for reasons other than progressive disease) was more common among ramucirumab- versus placebo-treated patients. In an exploratory analysis that censored for premature discontinuation, the HR for PFS favored the ramucirumab arm (HR 0.76), particularly in patients with gastric/GEJ cancer. An exploratory exposure–response analysis indicated that patients with higher ramucirumab exposure had longer OS. Conclusion The addition of ramucirumab to front-line mFOLFOX6 did not improve PFS in the ITT population. Clinicaltrials.gov identifier NCT01246960.

Introduction: FRα is overexpressed in 80% of OC and endometrial carcinoma (EC), with minimal expression in normal tissues. STRO-002 is a novel FRα-targeting ADC designed to circumvent limitations of current ADCs. STRO-002 was generated with Sutro’s cell-free antibody production system (XpressCF™) and site-specific conjugation (XpressCF+™) platform, which uses the non-natural amino acid pAMF. STRO-002 has a drug-antibody ratio (DAR) of 4 and contains the proprietary tubulin-targeting 3-aminophenyl hemiasterlin warhead SC209, a potent cytotoxin that is rapidly cleared and a weak substrate for efflux pumps. STRO-002 demonstrated potent cytotoxic activity in multiple FRα-positive tumor cell lines and significant therapeutic efficacy in OC xenograft models. Toxicology studies demonstrate dose-dependent and reversible neutropenia when STRO-002 is administered to cynomolgus monkeys. No ocular toxicity was observed. Herein we report additional preclinical efficacy in PDX models and preliminary safety experience of STRO-002 in patients (pts) with OC. PDX model methods: FRα expression was evaluated in EC PDX models by IHC. Single agent efficacy of 10 mg/kg STRO-002 was assessed in models with negative, low (+), medium (++) and high (+++) FRα expression. Phase 1 trial methods: STRO-002-GM1 is a first-in-human Phase I, open-label, multicenter, dose escalation (Part 1) study with dose expansion (Part 2) to identify the maximum tolerated dose (MTD), and recommended Phase II dose (RP2D) in pts with advanced, relapsed or refractory OC and EC. STRO-002 is given IV over an hour on Day 1 of each 21-day cycle until disease progression. Results: Statistically significant efficacy was observed in 60% of the FRα-positive PDX models tested, with STRO-002 response appearing to positively correlate with FRα expression levels. Though high FRα PDX models showed the highest response rates, some models with low and medium FRα also exhibited good responses. 5 pts with OC have completed at least one cycle (21 days) of STRO-002 at 3 dose levels: 0.5, 1.0, and 1.8 mg/kg and are evaluable for safety and toxicity. Median age is 63 (r, 52-64). Median ECOG performance status is 0 (r, 0-1). Median # of prior therapies is 6 (r, 2-8). Four pts have received PARP inhibitors. Median number of STRO-002 doses administered is 2 (r, 1-5). 3 additional pts have been treated at the 2.9 mg/kg dose level and continue in the first cycle. No grade ≥ 3 treatment-related adverse events (TRAEs) have been observed. 93% of AEs are grade 1 or 2. The most common TRAEs in ≥20 % of pts includes nausea, vomiting, abdominal pain, fatigue and insomnia. Four grade 3 events occurred in 2 pts after completion of the first cycle and were related to disease progression, including small intestine obstruction, gross hematuria, dehydration and vomiting. 2 pts have discontinued due to disease progression. 6 pts remain on treatment and dose escalation is ongoing. Conclusions: STRO-002 is the first ADC generated with cell-free protein synthesis technology and site-specific conjugation of a novel hemiasterlin linker-warhead to be tested in pts with solid tumors. The potent anti-tumor activity of STRO-002 in PDX models further supports the clinical development of this agent. The preliminary safety profile in 5 OC pts treated with STRO-002 is encouraging. MTD has not been reached, no DLTs have been observed and dose escalation is continuing. Updated results will be presented. This study is registered with clinicaltrials.gov identifier NCT03748186. Citation Format: Denise Uyar, Russell J Schilder, R Wendel Naumann, Fadi S Braiteh, Erika Hamilton, Sami Diab, John Moroney, Richard T Penson, Jennifer Smith, Cristina Abrahams, Michael Palumbo, Venita DeAlmeida, Shannon Matheny, Arturo Molina. Antitumor activity of STRO-002, a novel anti-folate receptor-α (FRα) antibody drug conjugate (ADC), in patient-derived xenograft (PDX) models and preliminary phase I dose escalation safety outcomes in patients with ovarian carcinoma (OC) [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference on Molecular Targets and Cancer Therapeutics; 2019 Oct 26-30; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2019;18(12 Suppl):Abstract nr C095. doi:10.1158/1535-7163.TARG-19-C095

Importance Atezolizumab (anti–programmed death ligand 1) has demonstrated safety and activity in advanced and metastatic urothelial carcinoma, but its long-term clinical profile remains unknown. Objective To report long-term clinical outcomes with atezolizumab therapy for patients with metastatic urothelial carcinoma. Design, Setting, and Participants Patients were enrolled in an expansion cohort of an ongoing, open-label, phase 1 study. Median follow-up was 37.8 months (range, >0.7 to 44.4 months). Enrollment occurred between March 2013 and August 2015 at US and European academic medical centers. Eligible patients had measurable disease per Response Evaluation Criteria in Solid Tumors version 1.1, Eastern Cooperative Oncology Group performance status 0 to 1, and a representative tumor sample. Programmed death ligand 1 expression on immune cells was assessed (VENTANA SP142 assay). Interventions Atezolizumab was given intravenously every 3 weeks until unacceptable toxic effects, protocol nonadherence, or loss of clinical benefit. Main Outcomes and Measures Primary outcome was safety. Secondary outcomes included objective response rate, duration of response, and progression-free survival. Response and overall survival were assessed in key baseline subgroups. Results Ninety-five patients were evaluable (72 [76%] male; median age, 66 years [range, 36-89 years]). Forty-five (47%) received atezolizumab as third-line therapy or greater. Nine patients (9%) had a grade 3 to 4 treatment-related adverse event, mostly within the first treatment year; no serious related adverse events were observed thereafter. One patient (1%) discontinued treatment due to a related event. No treatment-related deaths occurred. Responses occurred in 26% (95% CI, 18%-36%) of patients. Median duration of response was 22.1 months (range, 2.8 to >41.0 months), and median progression-free survival was 2.7 months (95% CI, 1.4-4.3 months). Median overall survival was 10.1 months (95% CI, 7.3-17.0 months); 3-year OS rate was 27% (95% CI, 17%-36%). Response occurred in 40% (95% CI, 26%-55%; n = 40) and 11% (95% CI, 4%-25%; n = 44) of patients with programmed death ligand 1 expression of at least 5% tumor-infiltrating immune cells (IC2/3) or less than 5% (IC0/1), respectively. Median overall survival in patients with IC2/3 and IC0/1 was 14.6 months (95% CI, 9.0 months to not estimable) and 7.6 months (95% CI, 4.7 to 13.9 months), respectively. Conclusions and Relevance Atezolizumab remained well tolerated and provided durable clinical benefit to a heavily pretreated metastatic urothelial carcinoma population in this long-term study. Trial Registration clinicaltrials.gov Identifier:NCT01375842

Crizotinib, an inhibitor of anaplastic lymphoma kinase (ALK), MET, and ROS1, is approved for treatment of patients with ALK‐positive or ROS1‐positive advanced non‐small‐cell lung cancer (NSCLC). However, ALK rearrangements are also implicated in other malignancies, including anaplastic large‐cell lymphoma and inflammatory myofibroblastic tumors (IMTs). In this ongoing, multicenter, single‐arm, open‐label phase 1b study (PROFILE 1013; NCT01121588), patients with ALK‐positive advanced malignancies other than NSCLC were to receive a starting dose of crizotinib 250 mg twice daily. Primary endpoints were safety and objective responses based on Response Evaluation Criteria in Solid Tumors version 1.1 or National Cancer Institute International Response Criteria. Forty‐four patients were enrolled (lymphoma, n = 18; IMT, n = 9; other tumors, n = 17). The objective response rate was 53% (95% confidence interval [CI], 28–77) for lymphoma, with 8 complete responses (CRs) and 1 partial response (PR); 67% (95% CI, 30–93) for IMTs, with 1 CR and 5 PRs; and 12% (95% CI, 2–36) for other tumors, with 2 PRs in patients affected by colon carcinoma and medullary thyroid cancer, respectively. The median duration of treatment was almost 3 years for patients with lymphoma and IMTs, with 2‐year progression‐free survival of 63% and 67%, respectively. The most common treatment‐related adverse events were diarrhea (45.5%) and vision disorders (45.5%), mostly grade 1. These findings indicate strong and durable activity of crizotinib in ALK‐positive lymphomas and IMTs. The safety profile was consistent with the known safety profile of crizotinib even with long‐term treatment.

Purpose Metastatic pancreatic ductal adenocarcinoma is characterized by excessive hyaluronan (HA) accumulation in the tumor microenvironment, elevating interstitial pressure and impairing perfusion. Preclinical studies demonstrated pegvorhyaluronidase alfa (PEGPH20) degrades HA, thereby increasing drug delivery. Patients and Methods Patients with previously untreated metastatic pancreatic ductal adenocarcinoma were randomly assigned to treatment with PEGPH20 plus nab-paclitaxel/gemcitabine (PAG) or nab-paclitaxel/gemcitabine (AG). Tumor HA levels were measured retrospectively using a novel affinity histochemistry assay. Primary end points were progression-free survival (PFS; overall) and thromboembolic (TE) event rate. Secondary end points included overall survival, PFS by HA level, and objective response rate. An early imbalance in TE events in the PAG arm led to a clinical hold; thereafter, patients with TE events were excluded and enoxaparin prophylaxis was initiated. Results A total of 279 patients were randomly assigned; 246 had HA data; 231 were evaluable for efficacy; 84 (34%) had HA-high tumors (ie, extracellular matrix HA staining ≥ 50% of tumor surface at any intensity). PFS was significantly improved with PAG treatment overall (hazard ratio [HR], 0.73; 95% CI, 0.53 to 1.00; P = .049) and for patients with HA-high tumors (HR, 0.51; 95% CI, 0.26 to 1.00; P = .048). In patients with HA-high tumors (PAG v AG), the objective response rate was 45% versus 31%, and median overall survival was 11.5 versus 8.5 months (HR, 0.96; 95% CI, 0.57 to 1.61). The most common treatment-related grade 3/4 adverse events with significant differences between arms (PAG v AG) included muscle spasms (13% v 1%), neutropenia (29% v 18%), and myalgia (5% v 0%). TE events were comparable after enoxaparin initiation (14% PAG v 10% AG). Conclusion This study met its primary end points of PFS and TE event rate. The largest improvement in PFS was observed in patients with HA-high tumors who received PAG. A similar TE event rate was observed between the treatment groups in stage 2 of the trial.

OBJECTIVE This study was conducted to understand treatment patterns and clinical outcomes in metastatic gastroenteropancreatic neuroendocrine tumor patients treated in a large community oncology network. METHODS This retrospective study used the McKesson Specialty Health/US Oncology Network iKnowMed electronic health record database with supplemental chart review. Eligibility criteria included a metastatic neuroendocrine tumor diagnosis between January 1, 2008, and to December 31, 2012; at least 2 US Oncology Network visits; and age at least 18 years. Follow-up was through October 31, 2014. RESULTS Among the 229 patients identified, median age was 64.0 years, 52.4% were male, 69.4% were white, and 62.9% were overweight/obese. Primary tumor sites included small bowel (47.6%), pancreas (31.4%), and stomach/colorectum (21.0%). There were 16.2% under observation without treatment, 52.4% received only somatostatin analogs (SSAs), and 31.4% received chemotherapy/targeted therapy during treatment. In the first-line setting (n = 192), 77% received SSAs, 12% received chemotherapy, and 10.9% received targeted therapy. Fifty percent of patients receiving octreotide had a relative dose intensity of less than 85%, and 16.7% received above-label dose. Toxicities of SSAs included diarrhea (18.2%), abdominal pain (16.9%), and fatigue (13.5%). Median overall survival from diagnosis was 68.0 months (95% confidence interval, 57.1 to not reached). CONCLUSIONS Most metastatic gastroenteropancreatic neuroendocrine tumor patients received systemic treatment with SSAs. Patient treatment used an individualized dosing approach. Overall survival and toxicity were consistent with the published literature.

Fadi Braiteh,1 Manish B Patel,2 Monika Parisi,2 Quanhong Ni,2 Siyeon Park,2,3 Claudio Faria2 1Comprehensive Cancer Centers of Nevada, University of Nevada School of Medicine, Las Vegas, NV, 2Celgene Corporation, Summit, NJ, 3The Ohio State University, Columbus, OH, USA Introduction: Despite a clinically relevant, statistically significant survival benefit with nab-paclitaxel plus gemcitabine and FOLFIRINOX vs single-agent gemcitabine for metastatic pancreatic cancer (mPC), little is known regarding their real-world effectiveness. We analyzed patients with mPC using a nationally representative electronic medical records database to address this unmet need.Methods: This retrospective analysis of the Navigating Cancer database compared outcomes among patients who received first-line nab-paclitaxel plus gemcitabine, FOLFIRINOX, or gemcitabine for mPC. Effectiveness, safety, and supportive care use were examined. nab-Paclitaxel plus gemcitabine was the reference for statistical comparisons.Results: Baseline characteristics were similar except age (oldest patients were in the gemcitabine cohort followed by nab-paclitaxel plus gemcitabine, then FOLFIRINOX). Patients receiving nab-paclitaxel plus gemcitabine (n=122) demonstrated similar time to treatment discontinuation (TTD; median, 3.4 vs 3.8 months; P=0.947) and database persistence (DP; median, 8.6 vs 8.6 months; P=0.534) vs FOLFIRINOX (n=80); however, TTD (median, 3.4 vs 2.2 months; P

Lessons LearnedThese negative phase II results for parsatuzumab highlight the challenges of developing an agent intended to enhance the efficacy of vascular endothelial growth factor inhibition without the benefit of validated pharmacodynamic biomarkers or strong predictive biomarker hypotheses. Any further clinical development of anti-EGFL7 is likely to require new mechanistic insights and biomarker development for antiangiogenic agents.BackgroundEGFL7 (epidermal growth factor-like domain 7) is a tumor-enriched vascular extracellular matrix protein that supports endothelial cell survival. This phase II trial evaluated the efficacy of parsatuzumab (also known as MEGF0444A), a humanized anti-EGFL7 IgG1 monoclonal antibody, in combination with modified FOLFOX6 (mFOLFOX6) (folinic acid, 5-fluorouracil, and oxaliplatin) bevacizumab in patients with previously untreated metastatic colorectal cancer (mCRC).MethodsOne-hundred twenty-seven patients were randomly assigned to parsatuzumab, 400 mg, or placebo, in combination with mFOLFOX6 plus bevacizumab, 5 mg/kg. Treatment cycles were repeated every 2 weeks until disease progression or unacceptable toxicity for a maximum of 24 months, with the exception of oxaliplatin, which was administered for up to 8 cycles.ResultsThe progression-free survival (PFS) hazard ratio was 1.17 (95% confidence interval [CI], 0.71–1.93; p = .548). The median PFS was 12 months for the experimental arm versus 11.9 months for the control arm. The hazard ratio for overall survival was 0.97 (95% CI, 0.46–2.1; p = .943). The overall response rate was 59% in the parsatuzumab arm and 64% in the placebo arm. The adverse event profile was similar in both arms.ConclusionsThere was no evidence of efficacy for the addition of parsatuzumab to the combination of bevacizumab and chemotherapy for first-line mCRC.

Introduction: PF-06801591 is a humanized IgG4 monoclonal antibody that binds to programmed cell death (PD-1) receptor, blocking its interaction with PD-1 ligands. In a phase I study (NCT02573259; dose-escalation) of 40 patients (pts) with multiple solid tumor types treated with PF-06891591 intravenously (IV) or subcutaneously (SC), 7 pts showed partial response. PF-06801591 was well tolerated at all doses. Biopsy samples were evaluated for predictive biomarkers and pharmacodynamic effects. Methods: Biopsy samples at baseline and on-treatment (IV:day 29; SC:day 36) were collected from 4 dose cohorts (IV:1, 3 and 10 mg/kg; SC:300 mg). Whole-exome sequencing (WES) and RNA-seq of biopsy tissue were used to estimate tumor mutation burden (TMB) and gene expression. Regression analysis was used to identify TMB/genes/pathways potentially associated with response in baseline tissue. Differential analysis of baseline and on-treatment biopsies identified genes/pathways potentially upregulated by PF-06801591. PD-L1 (clone SP-263; Ventana) expression was evaluated in tumor biopsies by immunohistochemistry (IHC) and pathologist scoring. Results: In a combined WES analysis of samples from baseline biopsies (all doses, n=24 pts), higher TMB was significantly associated with improved objective response (R^2=0.215, P=0.013). From RNA-seq analysis, genes positively associated with response were involved in interferon-gamma (IFNG) and PD-1 signaling, and cell cycle; CTLA4 was among the genes most significantly associated with response (P Conclusion: Based on a mixed set of tumor types with possible sensitivity to anti-PD-1, high TMB, IFNG signaling, and PD-L1 were associated with response to PF-06801591, as reported for other anti-PD-1 antibodies. Albeit based on a small sample size and diverse indication profile, baseline expression of CTLA4 appears to be highly associated with response and PD-L1 RNA levels may be better associated with response than protein expression by IHC. Increased expression of genes/pathways associated with adaptive immune activation in on-treatment biopsies indicates an active, immunomodulatory mechanism with anti-PD-1 therapy. This ongoing study will evaluate predictive biomarkers in dose-expansion cohorts of PF-06801591 in non-small cell lung cancer and urothelial cancer. Acknowledgments Study sponsor: Pfizer. Medical writing support: Chu Kong Liew (Engage Scientific Solutions), funded by Pfizer. Citation Format: Siwen Hu-Lieskovan, Fadi Braiteh, Juneko E. Grilley-Olson, Shobha Potluri, Xiao Wang, Alison Forgie, Vinicius Bonato, Jeffrey Chou, Melissa L. Johnson. Predictive biomarkers and pharmacodynamic changes in tumor RNA expression in a phase I study of anti PD-1 monoclonal antibody PF-06801591 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr CT046.

TPS4157 Background: C inhibits tyrosine kinases involved in tumor growth, angiogenesis, and immune regulation, including MET, VEGFR, and TAM kinases (Tyro3, AXL, MER). C is approved for treatment of aHCC after prior S based on improved overall survival (OS) vs placebo in the phase 3 CELESTIAL trial (Abou-Alfa NEJM 2018). Standard of care for first-line treatment of aHCC is tyrosine kinase inhibition with S or lenvatinib, and phase 3 trials of immune checkpoint inhibitors (ICIs) in first- and second- line aHCC are ongoing. C may promote an immune-permissive tumor environment, which could enhance response to ICIs. C is being evaluated in combination with the anti-PD-L1 antibody A in multiple tumor types including HCC in a phase 1 study; and dose, preliminary clinical activity, and safety have been established in aRCC (Agarwal Ann Oncol 2018). A in combination with bevacizumab, an anti-VEGF antibody, has shown preliminary clinical activity in first-line aHCC (Pishvaian Ann Oncol 2018). Here, we present the study design of a phase 3 trial of C+A vs S in pts with aHCC who have not received prior systemic therapy. Methods: This international, randomized, open-label phase 3 trial (NCT03755791) is evaluating the efficacy and safety of C+A vs S as first-line treatment for aHCC. Eligibility criteria include age ≥18 years, BCLC stage B or C, Child-Pugh A, ECOG PS 0 or 1, and measurable disease per RECIST 1.1. Patients are randomized 6:3:1 to an experimental arm of C (40 mg qd) + A (1200 mg infusion q3w), a control arm of S (400 mg bid), and an exploratory arm of C monotherapy (60 mg qd). 640 pts are planned at ~200 sites globally. Randomization is stratified by disease etiology (HBV [with or without HCV], HCV [without HBV], or other), region (Asia, other), and the presence of extrahepatic disease and/or macrovascular invasion (yes, no). OS and progression-free survival are coprimary endpoints and objective response rate is a secondary endpoint. Additional endpoints include safety, pharmacokinetics, and correlation of biomarker analyses with clinical outcomes. Enrollment in COSMIC-312 is ongoing. Clinical trial information: NCT03755791.

43 Background: PD-1 targeting with pembrolizumab or nivolumab leads to durable clinical benefits in patients (pts) with microsatellite instability-high (MSI-H) tumors. However, 30-35% of mCRC pts with MSI-H tumors will experience progressive disease (PD) as a best response when treated with anti-PD1 agents, highlighting the need of additional predictive biomarkers. Methods: We performed a retrospective multi-center clinical investigation to evaluate the impact of TMB, age, gender, stage at initial presentation, pattern of metastatic disease, tumor grade, and RAS/RAF status on response to anti-PD1/PD-L1 in MSI-H mCRC. TMB and MSI status were determined by hybrid capture-based next-generation sequencing (Foundation Medicine [FM]). The TMB distribution in MSI-H CRC was estimated from a large data set from FM. Results: 22 eligible MSI-H mCRC pts were identified across 5 cancer centers: 19 pts received pembrolizumab, 1 pt received nivolumab, 1 pt received nivolumab + ipilimumab, and 1 pt received durvalumab + tremelimumab. Among tested variables, TMB (as a continuous variable) showed the strongest association with an objective response (OR; p < 0.001). Also, both univariate and multivariate analyses supported that TMB serves as an independent prognostic variable in predicting progression-free survival (PFS; p < 0.001 and p < 0.01, respectively). Using log-rank statistics, the optimal predictive cut-point for TMB was estimated between 37-41 mutations/Mb to dichotomize pts into TMBhigh and TMBlow groups. All 13 pts (100%) with TMBhigh had an OR, while only 2/9 (22%) pts with TMBlow had an OR and 6/9 had PD. The median PFS for TMBhigh pts has not been reached (no progressors, median follow-up > 18 mos), while the median PFS for TMBlow pts was 2 mos. Amongst 821 MSI-H CRC cases tested at FM, the 25th, 35th, 50th and 75th percentile TMB cutoffs were 33.1, 37.4, 46.1, and 61.8 mutations/Mb, respectively. Our optimal TMB cut-point range suggests that MSI-H mCRC with the lowest 35th percentile of TMB have a low likelihood of benefit from anti-PD1. Conclusions: These TMB findings require validation in prospective trials and may guide the sequencing of PD-1 inhibitor monotherapy in MSI-H mCRC.

Purpose: To determine the MTD and to assess the safety, tolerability, and potential activity of LB-100, a first-in-class small-molecule inhibitor of protein phosphatase 2A (PP2A) in adult patients with progressive solid tumors. Experimental Design: LB-100 was administered intravenously daily for 3 days in 21-day cycles in a 3 + 3 dose escalation design. Results: There were 29 patient entries over 7 dose escalations. One patient stopped treatment after one dose because of an acute infection and was reenrolled after recovery; each course was analyzed as a separate patient entry. Two patients had dose-limiting toxicity (reversible increases in serum creatinine or calculated serum creatinine clearance) at the 3.1 mg/m2 level. Probable or possible study drug-related grade 3 adverse events occurred in 6 (20.7%) patients [anemia (n = 2), decreased creatinine clearance, dyspnea, hyponatremia, and lymphopenia]. Ten (50%) of 20 response-evaluable patients had stable disease for four or more cycles. One patient with pancreatic adenocarcinoma had a partial response noted after 10 cycles, which was maintained for five additional cycles. The other patients achieving stable disease had one of the following: fibrosarcoma, chondrosarcoma, thymoma, atypical carcinoid of lung, or ovarian, testicular, breast (n = 2), and prostate cancer. The recommended phase II dose of LB-100 is 2.33 mg/m2 daily for 3 days every 3 weeks. Conclusions: The safety, tolerability, preliminary evidence of antitumor activity, and novel mechanism of action of LB-100 support its continued development alone and in combination with other therapies. Clin Cancer Res; 23(13); 3277–84. ©2016 AACR.

Outcomes are poor for patients with previously treated, advanced or metastatic non-small-cell lung cancer (NSCLC). The anti-programmed death ligand 1 (PD-L1) antibody atezolizumab is clinically active against cancer, including NSCLC, especially cancers expressing PD-L1 on tumour cells, tumour-infiltrating immune cells, or both. We assessed efficacy and safety of atezolizumab versus docetaxel in previously treated NSCLC, analysed by PD-L1 expression levels on tumour cells and tumour-infiltrating immune cells and in the intention-to-treat population.In this open-label, phase 2 randomised controlled trial, patients with NSCLC who progressed on post-platinum chemotherapy were recruited in 61 academic medical centres and community oncology practices across 13 countries in Europe and North America. Key inclusion criteria were Eastern Cooperative Oncology Group performance status 0 or 1, measurable disease by Response Evaluation Criteria In Solid Tumors version 1.1 (RECIST v1.1), and adequate haematological and end-organ function. Patients were stratified by PD-L1 tumour-infiltrating immune cell status, histology, and previous lines of therapy, and randomly assigned (1:1) by permuted block randomisation (with a block size of four) using an interactive voice or web system to receive intravenous atezolizumab 1200 mg or docetaxel 75 mg/m(2) once every 3 weeks. Baseline PD-L1 expression was scored by immunohistochemistry in tumour cells (as percentage of PD-L1-expressing tumour cells TC3≥50%, TC2≥5% and50%, TC1≥1% and5%, and TC01%) and tumour-infiltrating immune cells (as percentage of tumour area: IC3≥10%, IC2≥5% and10%, IC1≥1% and5%, and IC01%). The primary endpoint was overall survival in the intention-to-treat population and PD-L1 subgroups at 173 deaths. Biomarkers were assessed in an exploratory analysis. We assessed safety in all patients who received at least one dose of study drug. This study is registered with ClinicalTrials.gov, number NCT01903993.Patients were enrolled between Aug 5, 2013, and March 31, 2014. 144 patients were randomly allocated to the atezolizumab group, and 143 to the docetaxel group. 142 patients received at least one dose of atezolizumab and 135 received docetaxel. Overall survival in the intention-to-treat population was 12·6 months (95% CI 9·7-16·4) for atezolizumab versus 9·7 months (8·6-12·0) for docetaxel (hazard ratio [HR] 0·73 [95% CI 0·53-0·99]; p=0·04). Increasing improvement in overall survival was associated with increasing PD-L1 expression (TC3 or IC3 HR 0·49 [0·22-1·07; p=0·068], TC2/3 or IC2/3 HR 0·54 [0·33-0·89; p=0·014], TC1/2/3 or IC1/2/3 HR 0·59 [0·40-0·85; p=0·005], TC0 and IC0 HR 1·04 [0·62-1·75; p=0·871]). In our exploratory analysis, patients with pre-existing immunity, defined by high T-effector-interferon-γ-associated gene expression, had improved overall survival with atezolizumab. 11 (8%) patients in the atezolizumab group discontinued because of adverse events versus 30 (22%) patients in the docetaxel group. 16 (11%) patients in the atezolizumab group versus 52 (39%) patients in the docetaxel group had treatment-related grade 3-4 adverse events, and one (1%) patient in the atezolizumab group versus three (2%) patients in the docetaxel group died from a treatment-related adverse event.Atezolizumab significantly improved survival compared with docetaxel in patients with previously treated NSCLC. Improvement correlated with PD-L1 immunohistochemistry expression on tumour cells and tumour-infiltrating immune cells, suggesting that PD-L1 expression is predictive for atezolizumab benefit. Atezolizumab was well tolerated, with a safety profile distinct from chemotherapy.F Hoffmann-La Roche/Genentech Inc.

Introduction The treatment options for squamous cell non–small-cell lung cancer (NSCLC) are limited. We assessed the efficacy and safety of onartuzumab plus platinum-doublet chemotherapy in previously untreated advanced squamous cell NSCLC. Patients and Methods The patients were randomized to receive onartuzumab plus paclitaxel plus carboplatin/cisplatin (n = 55) or placebo plus paclitaxel plus carboplatin/cisplatin (n = 54). Randomization was stratified by MET diagnostic status: MET immunohistochemistry (IHC)-positive (MET IHC 3+/2+) or MET IHC-negative (MET IHC 1+/0). The co-primary endpoints were investigator-assessed progression-free survival in the intent-to-treat and the MET IHC + populations. Results The risk of disease progression or death was similar between the 2 treatment arms in both the intent-to-treat (stratified hazard ratio, 0.95; 95% confidence interval, 0.63-1.43) and MET IHC + populations (unstratified hazard ratio, 1.27; 95% confidence interval, 0.69-2.32). Comparable results were obtained for overall survival and the objective response rate. In all safety-evaluable patients, the grade 3 to 5 adverse events occurring at a > 5% greater incidence in the onartuzumab-containing versus the placebo-containing arm were neutropenia (14.8% vs. 5.8%) and pulmonary embolism (5.6% vs. 0%). Eight patients died as a result of adverse events: 1 case each of pneumonitis, pneumonia, cardiac failure, and unexplained death in the onartuzumab arm and 1 case each of hemorrhage, cardiac arrest, hemoptysis, and febrile neutropenia in the placebo arm. Conclusion Studies using alternative assays of MET activation might help to clarify the role of onartuzumab. However, with the lack of clinical activity seen in the present study, the development of onartuzumab for squamous cell NSCLC will not be pursued further.

Introduction: Atezo (anti-PD-L1) + bev + chemo prolonged PFS vs bev + chemo in patients (pts) with 1L non-squamous mNSCLC in the randomized Ph 3 IMpower150 study regardless of PD-L1 expression. This analysis aims to further understand the efficacy of atezo + bev + chemo in key subgroups: PD-L1 expression subgroups defined by the SP142 and SP263 IHC assays, patients with EGFR/ALK genetic alterations and patients with liver metastases at baseline. Methods: Pts received atezo 1200 mg + bev 15 mg/kg + carboplatin (C) AUC 6 + paclitaxel (P) 200 mg/m2 (Arm B) or bev + C + P (Arm C) IV q3w. A co-primary endpoint (EP) was PFS in the ITT-WT (EGFR or ALK wild-type pts); a secondary EP was PFS in subgroups defined by PD-L1 expression on tumor cells (TC) and tumor-infiltrating immune cells (IC) with SP142. Retrospective analysis with SP263 was a prespecified exploratory EP. Results: In Arms B and C of the ITT-WT (n = 692), 503 pts had available tumor sections for SP263 testing (BEP). Pt characteristics in the ITT-WT and BEP were similar. A similar PFS benefit was observed for Arm B vs C across all PD-L1 expression subgroups defined by either assay, including pts with PD-L1-negative and PD-L1-low tumors (Table). PFS benefit with Arm B vs C was also observed in patients with EGFR or ALK genomic alterations, including patients with actionable EGFR mutations, and in patients with liver metastases at baseline (Table). Conclusion: PFS benefit with atezo + bev + chemo was observed across all PD-L1 subgroups, regardless of the IHC assay used. Additionally, clinically meaningful PFS benefit was observed in patients with EGFR/ALK genomic alterations, and in patients with liver metastases with this combination. Table. PFS in Biomarker Subgroups and Other Subgroups of Interest in IMpower150Median PFS, moPFSan (%)HRb (95% CI)P ValueArm BArm CITT-WT692 (100%)0.62 (0.52, 0.74) Citation Format: Marcin Kowanetz, Mark A. Socinski, Wei Zou, Mark McCleland, Nancy Yang, Ariel Lopez Chavez, Alexander Spira, Julien Mazières, Fadi Braiteh, David Shames, Alan Sandler, Martin Reck. IMpower150: Efficacy of atezolizumab (atezo) plus bevacizumab (bev) and chemotherapy (chemo) in 1L metastatic nonsquamous NSCLC (mNSCLC) across key subgroups [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr CT076.

187 Background: In the past decade, several therapies have been approved for mCRPC. However, most pts develop resistance and experience disease progression. Thus, there remains a high unmet need. Atezo (anti–PD-L1) blocks the interaction between PD-L1 and its receptors, PD-1 and B7.1, thereby restoring anti-tumor immunity. Atezo has demonstrated clinical efficacy in many tumor types. Here we report the clinical safety and activity of atezo in pts with mCRPC from a Phase Ia study (PCD4989g; NCT01375842). Methods: Eligible pts previously received enzalutamide and/or sipuleucel-T for mCRPC. Pts also had PSA or radiographic progression prior to enrollment. Atezo 1200mg was administered IV q3w. CT and bone scans were performed q6w for 24w and q12w thereafter (q6w if treatment beyond disease progression). Primary objectives were safety and tolerability; OS was an exploratory objective. mCRPC cohort–specific objectives included PSA response, radiographic progression per PCWG2 criteria, soft tissue response per RECIST v1.1 and immune-related response criteria (irRC). Survival follow-up data was collected ≈ every 3 mo until death or loss to follow-up. Results: The 15 pts in the initial mCRPC cohort were evaluated (clinical cutoff: December 31, 2016). 13 pts (87%) had received ≥ 2 prior lines of therapy for mCRPC. Median survival follow-up was 15.8 mo (range, 2.3-23.0). 9 pts (60%) had a treatment-related AE (TRAE); only 1 pt (7%) experienced a Gr 3 TRAE (hyponatremia). No Gr 4-5 TRAEs were reported. The landmark 12-mo OS rate was 55.6% (95% CI: 27.4, 83.7); median OS was not reached (range, 2.3-23.0 mo). Median PFS was 3.4 mo (95% CI: 2.3, 5.7); the 6-mo PFS rate was 26.7% (95% CI: 4.3, 49.1). 1 pt (9%) had a PR per irRC (irPR); 5 pts (45%) had SD per RECIST v1.1 and irRC. 2 pts (13%) had a ≥ 50% decrease in PSA from baseline. The pt who experienced an irPR had increased CD8 expression and expansion of T-cell clones on study treatment. Conclusions: Atezo was well tolerated and demonstrated long-term disease control in pts with heavily pretreated mCRPC, with a 12-mo OS rate of 55.6%. Preliminary biomarker analyses from the pt who experienced an irPR were suggestive of an activated immune response. Clinical trial information: NCT01375842.

[1] Abrams TJ, Lee LB, Murray LJ, Pryer NK, Cherrington JM. SU11248 inhibits KIT and platelet-derived growth factor receptor beta in preclinical models of human small cell lung cancer. Mol Cancer Ther 2003;/2:/471 8. [2] Mendel DB, Laird AD, Xin X, Louie SG, Christensen JG, Li G, et al. In vivo antitumor activity of SU11248, a novel tyrosine kinase inhibitor targeting vascular endothelial growth factor and platelet-derived growth factor receptors: Determination of a pharmacokinetic/pharmacodynamic relationship. Clin Cancer Res 2003;/9:/327 37. [3] O’Farrell AM, Abrams TJ, Yuen HA, Ngai TJ, Louie SG, Yee KW, et al. SU11248 is a novel FLT3 tyrosine kinase inhibitor with potent activity in vitro and in vivo. Blood 2003;/101:/3597 605. [4] Pfizer Inc., data on file [5] Faivre S, Demetri G, Sargent W, Raymond E. Molecular basis for sunitinib efficacy and future trial development. Nat Rev Drug Discov 2007;/6:/734 45. [6] Faivre S, Delbaldo C, Vera K, Robert C, Lozahic S, Lassau N, et al. Safety, pharmacokinetic, and antitumor activity of SU11248, a novel oral multitarget tyrosine kinase inhibitor, in patients with cancer. J Clin Oncol 2006;/143:/313 4. [7] Blay JY, Le Cesne A, Ray-Coquard I, Bui B, Duffaud F, Delbaldo C, et al. Prospective multicentric randomized phase III study of imatinib in patients with advanced gastrointestinal stromal tumors comparing interruption versus continuation of treatment beyond 1 year: The French Sarcoma Group. J Clin Oncol 2007;/25:/1107 13. [8] Blay JY, George S, Casali PG Le Cesne A, Morgan JA, Tyler A, et al. Clinical benefit of continuous daily dosing of sunitinib in patients (pts) with advanced gastrointestinal stromal tumor (GIST). Ann Oncol 2006;17(Suppl 9):508P (Abstract). [9] Escudier B, Roigas J, Gillessen S, Srinivas S, Pisa P, Vogelzang N, et al. Continuous daily administration of sunitinib malate (SU11248)-phase II study in patients (pts) with cytokine-refractory metastatic renal cell carcinoma (MRCC). Ann Oncol 2006;17(Suppl 9):436O (Abstract). [10] Mancuso MR, Davis R, Norberg SM, O’Brien S, Sennino B, Nakahara Yao VJ, et al. Rapid vascular regrowth in tumours after reversal of VEGF inhibition. J Clin Invest 2006;/116:/ 2610 21.

Palliative care services can decrease physical and psychosocial distress in patients with advanced cancer. However, most patients with cancer die without access to palliative care services (APCS), and patterns of referral are not well understood. The purpose of this study was to determine predictors of patients' access to palliative care.We reviewed patient records from the computerized database at UT M. D. Anderson Cancer Center over 2 (2003 and 2004) to determine differences in characteristics and outcomes between patients with and without APCS. APCS was defined as a palliative care consultation and follow-up or transfer to the palliative care unit.A total of 499 of 1453 (34%) inpatients who died at our cancer center had APCS. There were no significant differences in race, age, or insurance status between the APCS groups. The two major predictors of a low rate of APCS were hematologic malignancies (20% rate of APCS versus 44% for solid tumors, p0.0001) and intensive care unit (ICU) admission (15% versus 52% for non-ICU admission, p0.0001). Patients with hematologic malignancies who were admitted to the ICU had the lowest APCS rate (10%, p0.0001). The median relative cost of care per patient for decedents with APCS was 0.62 compared to non-referred patients (p0.0001).APCS was lower among patients with hematologic malignancies and those admitted to the ICU. APCS resulted in a lower cost of care. Mortality in comprehensive cancer centers is quite variable among different primary malignancies. More research is needed to better define patterns of referral.

Why does it seem that, repeatedly, when a new treatment with a striking effect is discovered in the cancer field, it is effective for a very rare cancer type? For example, groundbreaking therapeutic discoveries have been made for extremely uncommon malignancies such as hairy cell leukemia, chronic myelogenous leukemia, seminoma, gastrointestinal stromal tumor, (del)5q myelodysplastic syndrome, and acute promyelocytic leukemia. In contrast, progress in the most common and most intensively studied tumors—lung, breast, prostate, and colon cancer—has been slow and incremental. We hypothesize that the reason for this phenomenon is that the pathophysiologic basis for a tumor being rare is one and the same as the reason that it may ultimately be so treatable. That is, if a cancer can be derived only via a single aberrant molecular genetic aberration, then it should be both rare and easily targeted by a molecular cancer therapeutic approach. If, on the other hand, many distinct pathways can lead to the development of a specific tumor type, it should occur much more commonly and be significantly more difficult to treat. The corollary to our hypothesis is the prediction that new therapies will continue to show their most salutary effects in rare cancers. Furthermore, only by stratifying the common tumors, especially when using targeted agents, into the molecular subsets of diseases that compose them are we likely to achieve a substantial effect in these disorders. [Mol Cancer Ther 2007;6(4):1175–9]

Summary Background Klebsiella pneumoniae -associated liver abscesses have distinct clinical and epidemiologic features. Methods We report the unusual case of an American patient with a K. pneumoniae -associated liver abscess and septic spread to other organs. We additionally present a comprehensive review of K. pneumoniae -associated liver abscess syndromes in adults. Results We identified three distinct K. pneumoniae liver abscess syndromes: the polymicrobial liver abscess, the monomicrobial cryptogenic noninvasive liver abscess, and the monomicrobial cryptogenic invasive K. pneumoniae -associated liver abscess (CIKPLA) syndromes, with distinct clinical, epidemiologic and outcome features. CIKPLA syndrome typically affects diabetic patients, mainly in Southeast Asia, and is complicated by septic spread to other organs. Conclusions The community-acquired, monomicrobial, K. pneumoniae -associated liver abscess syndromes that typically occur in the USA are mainly noninvasive and affect Asian or Hispanic persons. However, this report provides an alert that CIKPLA syndrome can occur in North America, and physicians need to be aware of it.

Purpose: To assess the safety and tolerability of the small-molecule allosteric MEK inhibitor refametinib combined with sorafenib, in patients with advanced solid malignancies. Experimental Design: This phase I dose-escalation study included an expansion phase at the maximum tolerated dose (MTD). Patients received refametinib/sorafenib twice daily for 28 days, from a dose of refametinib 5 mg plus sorafenib 200 mg to a dose of refametinib 50 mg plus sorafenib 400 mg. Plasma levels of refametinib, refametinib metabolite M17, and sorafenib were measured for pharmacokinetic assessments. Tumors were biopsied at the MTD for analysis of MEK pathway mutations and ERK phosphorylation. Results: Thirty-two patients were enrolled in the dose-escalation cohort. The MTD was refametinib 50 mg twice daily plus sorafenib 400 mg twice daily. The most common treatment-related toxicities were diarrhea and fatigue. Refametinib was readily absorbed following oral administration (plasma half-life of ∼16 hours at the MTD), and pharmacokinetic parameters displayed near-dose proportionality, with less than 2-fold accumulation after multiple dosing. Another 30 patients were enrolled in the MTD cohort; 19 had hepatocellular carcinoma. The combination was associated with significantly reduced ERK phosphorylation in 5 out of 6 patients biopsied, with the greatest reductions in those with KRAS or BRAF mutations. Disease was stabilized in approximately half of patients, and 1 patient with colorectal cancer achieved a partial response at the MTD lasting approximately 1 year. Conclusions: In this phase I study, refametinib plus sorafenib was well tolerated, with good oral absorption, near-dose proportionality, and target inhibition in a range of tumor types. Clin Cancer Res; 22(10); 2368–76. ©2015 AACR.

Purpose: Reliable detection of drug-sensitive activating EGFR mutations is critical in the care of advanced non–small cell lung cancer (NSCLC), but such testing is commonly performed using a wide variety of platforms, many of which lack rigorous analytic validation. Experimental Design: A large pool of NSCLC cases was assayed with well-validated, hybrid capture–based comprehensive genomic profiling (CGP) at the request of the individual treating physicians in the course of clinical care for the purpose of making therapy decisions. From these, 400 cases harboring EGFR exon 19 deletions (Δex19) were identified, and available clinical history was reviewed. Results: Pathology reports were available for 250 consecutive cases with classical EGFR Δex19 (amino acids 743–754) and were reviewed to assess previous non-hybrid capture–based EGFR testing. Twelve of 71 (17%) cases with EGFR testing results available were negative by previous testing, including 8 of 46 (17%) cases for which the same biopsy was analyzed. Independently, five of six (83%) cases harboring C-helical EGFR Δex19 were previously negative. In a subset of these patients with available clinical outcome information, robust benefit from treatment with EGFR inhibitors was observed. Conclusions: CGP identifies drug-sensitive EGFR Δex19 in NSCLC cases that have undergone prior EGFR testing and returned negative results. Given the proven benefit in progression-free survival conferred by EGFR tyrosine kinase inhibitors in patients with these alterations, CGP should be considered in the initial presentation of advanced NSCLC and when previous testing for EGFR mutations or other driver alterations is negative. Clin Cancer Res; 22(13); 3281–5. ©2016 AACR.

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. Table.EfficacyResponses per RECIST v1.1 (irRC efficacy results presented in text)1L2L+PD-L1 IC2/3PD-L1 IC0/1Alln = 19n = 93n = 71n = 37N = 112ORR, % (95%CI)26% (9, 51)7% (2, 14)13% (6, 23)5% (1, 18)10% (5, 17)CR, n21303PR, n35628SD, n31210415CBR, %42%19%27%16%23%Median (range) DoR, mo21 (8+ to 26+)NE (3 to 13+)21 (3 to 26)NE (10 to 10+)21 (3 to 26+)OS1L2L+PD-L1 IC2/3PD-L1 IC0/1All ptsn = 19n = 94n = 71n = 38N = 1131 y OS (95% CI)63% (37, 89)37% (26, 47)45% (32, 58)37% (21, 53)41% (31, 51)2 y OS (95% CI)47% (14, 80)18% (8, 27)28% (15, 41)NE22% (12, 32)3 y OS (95% CI)NE18% (8, 27)28% (15, 41)NE22% (12, 32)CBR; clinical benefit rate, defined as CR, PR or SD for ≥12 weeks. DoR, duration of response; NE, not evaluable.+, censored. 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

1084 Background: Napabucasin is a first-in-class cancer stemness inhibitor, identified by its ability to inhibit STAT3-driven gene transcription and spherogenesis of cancer stem cells (Li et al PNAS 112 (6):1839, 2015). Napabucasin has shown potent synergistic preclinical anti-tumor activity with paclitaxel (PTX). In a phase Ib dose escalation study in patients (pts) with advanced solid tumors, Napabucasin plus weekly paclitaxel was well tolerated. A phase II expansion cohort was opened for pts with previously treated metastatic breast cancer (MBC). Methods: Pts with metastatic MBC for whom weekly PTX was a reasonable treatment option received Napabucasin 240, 480, or 500 mg orally, twice daily in combination with paclitaxel 80 mg/m2 IV weekly on 3 of every 4 weeks. Adverse events were evaluated using CTCAE v4.03 and objective tumor assessments were obtained every 8 weeks per RECIST 1.1 criteria. Results: A total of 50 pts were enrolled including 34 with triple-negative disease (negative for estrogen receptor [ER], progesterone receptor [PR], and Her2 and no prior history of positive receptor status). There were 9 pts positive for ER, PR, or Her2 and refractory to targeted agents, and 7 pts with conversion to triple-negative disease from pathology previously positive for ER, PR or Her2. Pts were heavily pre-treated, having received a median of 5 prior lines of systemic therapy. All but 3 patients had received previous systemic treatment with a taxane. Napabucasin + PTX was well tolerated. Grade 3 AE occurring in ≥ 5% patients was diarrhea (n = 4), and 1 pt had grade 4 diarrhea. The objective response rate (ORR), disease control rate (DCR), median progression free survival (mPFS), and median overall survival (mOS) for all pts and for each sub-group are summarized in the table. Conclusions: Napabucasin (BBI-608) plus weekly paclitaxel has demonstrated safety, tolerability, and encouraging signs of anti-cancer activity in pts with pretreated metastatic breast cancer. Further clinical evaluation of this combination regimen in controlled trials is warranted. Clinical trial information: NCT01325441. [Table: see text]

4077 Background: Napabucasin, a first-in-class cancer stemness inhibitor in clinical development, suppresses cancer stemness by targeting STAT3-driven gene transcription. Amcasertib targets multiple serine threonine stemness kinases and inhibits Nanog and other cancer stemness pathways. Preclinically, potent and broad-spectrum anti-cancer activity was observed in vitro and in vivo, alone and in combination with sorafenib. Methods: A phase Ib/II open-label, multi-center study in adult patients with advanced HCC who have not received prior systemic chemotherapy was performed to determine the safety, tolerability, and recommended Phase II dose (RP2D) ,according to the criteria for DLT and for dose-escalation of Napabucasin (Arm 1), administered at 160 mg BID (dose level I) and at 240 mg BID (dose level II) in combination with sorafenib and of Amcasertib (Arm 2), administered at 100 mg QD (dose level I) and at 200 mg QD (dose level II) in combination with sorafenib. Results: 20 pts were enrolled, 10 in Arm 1 and 10 in Arm 2. 12 patients were evaluable for DLT determination; 2 pts d/c prior to starting protocol treatment; 11 pts received evaluation by RECIST, 6 pts in Arm 1 and 5 pts in Arm 2. The safety profile was consistent with that of each agent as monotherapy and most common AEs were attributed to (Sor) and included rash, PPE, grade 1/2 diarrhea, nausea, abdominal cramps, and vomiting. No signs of drug-drug interactions were observed in pharmacokinetics. Among all patients who received RECIST evaluation, Disease Control Rate (DCR=CR+PR+SD) for Arm 1 was 100% (6/6pts) and 100% (5/5pts) for Arm 2. DCR in ITT Arm 1 population was 67% and 50% in Arm 2. Median OS is not yet reached. Conclusions: In this phase Ib study, RP2D were determined for napabucasin and amcasertib to be safely combined with sorafenib at full dose, showing encouraging anti-tumor activity in patients with HCC who have not received prior systemic chemotherapy. A randomized phase II is schedule to start. Clinical trial information: NCD02279719. [Table: see text]