Sitravatinib Plus Pembrolizumab in Patients With Advanced Treatment-Naïve PD-L1+ Non-Squamous NSCLC

This is a multicohort phase 2 study to evaluate the efficacy of pembrolizumab combined with the investigational drug sitravatinib in the frontline treatment of advanced, non-squamous PD-L1 positive NSCLC. For clinical analysis, there will be two patient cohorts defined by PD-L1 status: Cohort 1 for patients with PD-L1 Tumor Proportion Score (TPS) 1-49% and Cohort 2 for patients with TPS≥50%. The investigators will implement a Simon's two-stage design to evaluate the efficacy of sitravatinib in combination with pembrolizumab for each cohort separately. There will be two groups within each cohort of this study: the "main study population" (Group A) in which patients will receive pembrolizumab plus sitravatinib beginning on Cycle 1 Day 1 (C1D1), and a "pembrolizumab run-in population" (Group B) in which patients will receive pembrolizumab alone for 1 dose followed by pembrolizumab plus sitravatinib beginning C2D1. The primary endpoint of the trial is the ORR for patients treated with pembrolizumab plus sitravatinib in the main study population. The purpose of the pembrolizumab run-in population is to obtain tissue and blood samples from these patients to be used as controls for correlative studies and to determine the preliminary efficacy of pembrolizumab alone followed by the combination. Primary Objective (1) The primary objective of this study is to evaluate the efficacy of sitravatinib in combination with pembrolizumab in the front-line treatment of patients with advanced non-squamous PD-L1 positive NSCLC by measuring Objective Response Rate (ORR). Secondary Objectives 1. To evaluate other measures of efficacy including Overall Survival (OS), Progression Free Survival (PFS), Duration of Response (DOR) and Clinical Benefit Rate (CBR) in the first-line setting for patients with advanced, non-squamous, PD-L1 positive NSCLC treated with the combination of sitravatinib and pembrolizumab. 2. To evaluate the toxicity profile and tolerability of sitravatinib/pembrolizumab in advanced, treatment naïve, non-squamous, PD-L1 positive NSCLC. Exploratory Objectives: 1. To evaluate ORR, OS, PFS, DOR, and CBR in patients with advanced, non-squamous, treatment naïve, PD-L1 positive NSCLC who receive pembrolizumab run-in followed by pembrolizumab/sitravatinib combination therapy. 2. To evaluate the CNS activity of sitravatinib/pembrolizumab in patients with advanced, treatment naïve, PD-L1 positive NSCLC by measuring Intracranial Objective Response Rate (iORR) and Intracranial Duration of Response(iDOR) in patients with baseline CNS disease, and Intercranial Progression-Free Survival (iPFS) in all patients. 3. To study correlates of the adaptive and innate immune responses induced by sitravatinib and pembrolizumab treatment in both tumor tissue and peripheral blood. 4. To explore the association between tumor immune contexture and clinical benefit to sitravatinib and pembrolizumab.