Biomarker-directed, pembrolizumab-based combination therapy in non-small cell lung cancer: phase 2 KEYNOTE-495/KeyImPaCT trial interim results

Abstract

Although pembrolizumab confers clinical benefit in non-small cell lung cancer (NSCLC), only a subset of patients will respond due to a heterogenous tumor microenvironment. KEYNOTE-495/KeyImPaCT is an ongoing biomarker-directed, adaptively randomized phase 2 study investigating first-line pembrolizumab (200 mg every 3 weeks) + lenvatinib (20 mg daily), anti-CTLA-4 quavonlimab (25 mg every 6 weeks) or anti-LAG-3 favezelimab (200 mg or 800 mg every 3 weeks) in advanced NSCLC. Patients were categorized by T-cell-inflamed gene expression profile (Tcell_infGEP) and tumor mutational burden (TMB) status and randomly assigned 1:1:1 to receive pembrolizumab + lenvatinib, pembrolizumab + quavonlimab or pembrolizumab + favezelimab. The primary outcome was investigator-assessed objective response rate (ORR) per Response Evaluation Criteria in Solid Tumors version 1.1 using pre-specified efficacy thresholds for each biomarker-defined subgroup (>5% (Tcell_infGEP^lowTMB^non-high (group I)), >20% (Tcell_infGEP^lowTMB^high (group II) and Tcell_infGEP^non-lowTMB^non-high (group III)) and >45% (Tcell_infGEP^non-lowTMB^high (group IV))). Secondary outcomes were progression-free survival, overall survival and safety. At data cutoff, ORR ranges were 0-12.0% in group I, 27.3-33.3% in group II, 13.6-40.9% in group III and 50.0-60.0% in group IV. ORR with pembrolizumab + lenvatinib in group III met the pre-specified efficacy threshold. The safety profile of each treatment arm was consistent with the known safety profile of each combination. These data demonstrate the feasibility of prospective Tcell_infGEP and TMB assessment to study the clinical activity of first-line pembrolizumab-based combination therapies in advanced NSCLC. ClinicalTrials.gov registration: NCT03516981 .