Introduction: Rovalpituzumab tesirine (Rova-T) is an antibody-drug conjugate targeting DLL3, an atypical Notch ligand expressed in SCLC tumors. We evaluated the efficacy of Rova-T versus placebo as maintenance therapy in patients with extensive-stage-SCLC after platinum-based chemotherapy.Methods: MERU was a phase 3 randomized, doubleblinded, placebo-controlled study. Patients without disease progression after four cycles of platinum-based, front-line chemotherapy were randomized in a 1:1 ratio to receive 0.3 mg/kg Rova-T or placebo (every 6 wk, omitted every third cycle). Primary efficacy end points were progression-free survival (PFS) evaluated by the Central Radiographic Assessment Committee and overall survival (OS) in patients with DLL3-high tumors.Results: Median age of all randomized patients (N ¼ 748) was 64 years; 78% had TNM stage IV disease. At futility analysis of the subset with DLL3-high tumors, the hazard ratio for OS was 1.07 (95% confidence interval: 0.84-1.36) favoring the placebo arm, with median OS of 8.5 and 9.8 months in the Rova-T and placebo arms, respectively; futility criteria were met. Rova-T significantly improved PFS versus placebo by investigator assessment (4.0 versus 1.4 mo, hazard ratio ¼ 0.48, p < 0.001). Any-grade adverse events (!20%) in the Rova-T arm were pleural effusion (27%), decreased appetite (27%), peripheral edema (26%), photosensitivity reaction (25%), fatigue (25%), nausea (22%), and dyspnea (21%).Conclusions: Because of the lack of survival benefit in the Rova-T arm, the study did not meet its primary end point and was terminated early. As a result, the Central Radiographic Assessment Committee evaluation of PFS was not performed. The frequency of grade greater than or equal to 3 and drug-related toxicities were higher with Rova-T versus placebo. Rova-T was associated with unique toxicities, such as pleural and pericardial effusions, photosensitivity reaction, and peripheral edema, which should be carefully considered in the population with extensive-stage-SCLC.

Health regulatory approval of the 1.5 microg/kg body weight dose of pegylated interferon (PEG-I) alpha-2b in combination with ribavirin for the treatment of chronic hepatitis C was based on a study using PEG-I alpha-2b at doses of only 0.5 and 1.5 microg/kg body weight (BW), in spite of the previously shown flat dose-response curve at doses of > or =1.0 microg/kg. Our aim was to compare PEG-I alpha-2b 1.0 microg/kg with 1.5 microg/kg, both in combination with ribavirin. Open-label, randomized study in 227 patients with biopsy-proven chronic hepatitis C (Metavir < or =F2), receiving oral ribavirin (400 mg, twice daily) in combination with subcutaneous PEG-I alpha-2b (1.0 or 1.5 microg/kg, once weekly) for 24 weeks (genotype 2 or 3), or 48 weeks (other genotypes), followed by a 24-week drug-free period. Virologic response rates did not differ between the two doses of PEG-I alpha-2b: in patients infected with hepatitis C virus (HCV) genotype 1 or 4 treated with PEG-I 1.0 microg/kg BW, 38% (22/58) had a sustained virologic response compared with 39% (27/70) in the PEG-I 1.5 microg/kg BW dose group (P = ns). The corresponding values in patients infected with HCV genotype 2 or 3 were 71% (39/55) and 81% (29/36) respectively (P = ns). Adverse events led to transient or permanent dose reductions in fewer patients in the 1.0 microg/kg BW dose group (48/113 patients; 42%) than in the 1.5 microg/kg BW dose group (63/106 patients; 59%, P = 0.015). Furthermore, 89% of patients treated for 24 weeks but only 58% of patients treated for 48 weeks (P < 0.001) tolerated the treatment without relevant dose reduction or premature termination. In combination with ribavirin, PEG-I alpha-2b 1.0 microg/kg was as effective as 1.5 microg/kg but was better tolerated in patients with chronic hepatitis C and up to moderate fibrosis.

PurposeImmune checkpoint inhibition (ICI) therapy has improved patient outcomes in advanced non-small cell lung cancer (NSCLC), but better biomarkers are needed. A clinically validated, blood-based proteomic test, or host immune classifier (HIC), was assessed for its ability to predict ICI therapy outcomes in this real-world, prospectively designed, observational study.Materials and methodsThe prospectively designed, observational registry study INSIGHT (Clinical Effectiveness Assessment of VeriStrat® Testing and Validation of Immunotherapy Tests in NSCLC Subjects) (NCT03289780) includes 35 US sites having enrolled over 3570 NSCLC patients at any stage and line of therapy. After enrolment and prior to therapy initiation, all patients are tested and designated HIC-Hot (HIC-H) or HIC-Cold (HIC-C). A prespecified interim analysis was performed after 1-year follow-up with the first 2000 enrolled patients. We report the overall survival (OS) of patients with advanced stage (IIIB and IV) NSCLC treated in the first-line (ICI-containing therapies n=284; all first-line therapies n=877), by treatment type and in HIC-defined subgroups.ResultsOS for HIC-H patients was longer than OS for HIC-C patients across treatment regimens, including ICI. For patients treated with all ICI regimens, median OS was not reached (95% CI 15.4 to undefined months) for HIC-H (n=196) vs 5.0 months (95% CI 2.9 to 6.4) for HIC-C patients (n=88); HR=0.38 (95% CI 0.27 to 0.53), p<0.0001. For ICI monotherapy, OS was 16.8 vs 2.8 months (HR=0.36 (95% CI 0.22 to 0.58), p<0.0001) and for ICI with chemotherapy OS was unreached vs 6.4 months (HR=0.41 (95% CI 0.26 to 0.67), p=0.0003). HIC results were independent of programmed death ligand 1 (PD-L1). In a subgroup with PD-L1 ≥50% and performance status 0–1, HIC stratified survival significantly for ICI monotherapy but not ICI with chemotherapy.ConclusionBlood-based HIC proteomic testing provides clinically meaningful information for immunotherapy treatment decision in NSCLC independent of PD-L1. The data suggest that HIC-C patients should not be treated with ICI alone regardless of their PD-L1 expression.

764 Background: Inhibiting the transforming growth factor β (TGF-β) pathway, which plays a key role in tumor immunosuppression, may enhance the response to programmed death 1/programmed death ligand 1 (PD-1/PD-L1) monoclonal antibodies (mAbs). M7824 (MSB0011359C) is an innovative first-in-class bifunctional fusion protein composed of a mAb against PD-L1 fused with the extracellular domain of TGF-β receptor II, which serves as a TGF-β “trap.” We report results in patients (pts) with heavily pretreated colorectal cancer (CRC), an area of high unmet need since these pts no longer respond to standard therapies. Methods: In this expansion cohort of the ongoing, phase 1, open-label trial NCT02517398, pts with heavily pretreated (≥3rd line) advanced CRC receive M7824 1200 mg q2w until confirmed progressive disease (PD), unacceptable toxicity or trial withdrawal. The primary objective is best overall response (BOR) per RECIST v1.1; secondary objectives include safety/tolerability. Results: As of 28 June 2017, 32 heavily pretreated pts with advanced CRC (87.5% had ≥3 prior therapies) received M7824 for a median duration of 7.1 (range: 2-38) weeks; 2 pts remained on treatment. Among the 29 evaluable pts, 1 had a confirmed partial response (PR; ongoing at 8 months), 1 had stable disease (SD) and 27 had PD as BOR per independent read. The pt with a PR had CRC that was microsatellite stable (MSS), consensus molecular subtype (CMS) 4, KRAS mutant (mt) and PD-L1+; this pt had the highest tumor cell PD-L1 expression in our cohort (20%; PD-L1 expression was generally low among the other 24 pts with available results). 4 pts (12.5%) experienced 5 different grade 3 treatment-related adverse events (AEs; adrenal insufficiency, anemia, blood bilirubin increased, enteritis [leading to discontinuation] and fatigue); there were no grade ≥4 treatment-related AEs or treatment-related deaths. Conclusions: In heavily pretreated pts with advanced CRC, 1 pt (MSS, CMS 4, KRAS mt and PD-L1+) had a durable PR, 1 had SD and 27 had PD as BOR. M7824 showed a manageable safety profile. Updated data – including PD-L1, TGF-β and CMS results – will be presented. A study in pts with CMS 4 is in preparation. Clinical trial information: NCT02517398.

Background Esophageal adenocarcinoma patients have limited treatment options. TGF-β can be upregulated in esophageal adenocarcinoma, and blocking this pathway may enhance clinical response to PD-(L)1 inhibitors. Bintrafusp alfa is a firstin-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. Objective The objective of this study was to investigate the efficacy and safety of bintrafusp alfa in patients with advanced, post-platinum esophageal adenocarcinoma, unselected for PD-L1 expression. Patients and MethodsIn this phase 1 study, patients with post-platinum, PD-L1-unselected esophageal adenocarcinoma received bintrafusp alfa 1200 mg every 2 weeks until disease progression, unacceptable toxicity, or withdrawal. The primary endpoint was confirmed best overall response per RECIST 1.1 by independent review committee (IRC). Results By the database cutoff of 24 August 2018, 30 patients (80.0% had two or more prior anticancer regimens) received bintrafusp alfa for a median of 6.1 weeks. The confirmed objective response rate (ORR) per IRC was 20.0% (95% CI 7.7-38.6); responses lasted 1.3-8.3 months. Most responses (83.3%) occurred in tumors with an immune-excluded phenotype. Investigator-assessed confirmed ORR was 13.3% (95% CI 3.8-30.7). Nineteen patients (63.3%) had treatment-related adverse events: seven patients (23.3%) had grade 3 events; no grade 4 events or treatment-related deaths occurred. Conclusions Bintrafusp alfa showed signs of clinical efficacy with a manageable safety profile in patients with heavily pretreated, advanced esophageal adenocarcinoma. Clinical Trials Registration NCT02517398.

e14579 Background: The use of immunotherapy is exponentially increasing in treatment of patients with advanced solid tumors. However, the response rates vary significantly between different tumor types and even within same tumor type (e.g. in lung cancer approx. 1 in 4 patients respond to immunotherapy). In order to better identify patients that will respond to immunotherapy, several markers have been proposed. Tumor mutation burden (TMB) has emerged more recently as a quantitative marker that can help predict responses to immunotherapies across different cancers, including melanoma, lung cancer and bladder cancer. TMB is a measure of the overall number of somatic protein coding mutations occurring in the tumor specimen. Methods: We analyzed 54 consecutive patients treated with immunotherapy at our institution for which we had genomic sequencing (FoundationOne). There were 39 lung cases and 15 non-lung (GI, GU, sarcoma). For 30 cases we had TMB data. Favorable response was defined as stable disease or response to therapy at 3 months. The relationship between TMB and tumor response was explored using ROC analysis. Results: The probability of a favorable response to immunotherapy in our patient dataset was 57% (31/54 patients). Among the patients with known TMB 60% (18/30) had a favorable response (stable disease or response to therapy). The favorable response rate for tumors originating in the lung was 64% (25/39) and for non-lung primary tumors was 40% (6/15). The difference was not statistically significant, with p = 0.12. Higher TMB values were correlated with increased probability of a favorable response. ROC analysis demonstrated an Az of 74% for TMB values in differentiating between patients with and without a favorable response. A TMB cutoff value of 8 mutations/megabase yielded a sensitivity of 95% and a specificity of 58% for predicting favorable response. Conclusions: In our data base 57%of patients with different solid cancers had favorable response to immunotherapy, in second line and beyond .Higher TMB correlated with higher likelihood of response to immunotherapy, independent of the primary site of cancer.

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