Pembrolizumab alone or with chemotherapy for PD-L1 positive NSCLC: A network meta-analysis of randomized trials.

Abstract

9087 Background: Pembrolizumab (P) has replaced chemotherapy (C) as first-line treatment for advanced non-small cell lung cancer (NSCLC) with tumor PD-L1 expression > / = 50%. Among PD-L1 unselected patients, P+C is superior to C alone. This network meta-analysis compared P alone with P+C in patients with > / = 50% PD-L1 positive NSCLC. Methods: An indirect network was constructed to compare P and P+C through the control arms of the Keynote 024, 189 and 407 (PD-L1 > / = 50% subgroup) trials. Baseline characteristics and chemotherapy outcomes were examined for heterogeneity. Overall survival (OS), progression-free survival (PFS), objective response rate (ORR) and toxicities including immune-related adverse events (irAE) were extracted from trial results. Toxicity results were unavailable for the PD-L1 > / = 50% subgroups of KN 189 & 407, so overall study results were used. Survival outcomes are expressed as hazard ratios (HRs) or restricted mean survival time (RMST) ratios, and toxicity and ORR as risk difference (RD). Results: 507 patients were included: 154 on P, 430 on C and 483 on P+C. Patient characteristics across trials were similar in age, sex, performance status and smoking history. All trials had similar chemotherapy outcomes (PFS 6, 4.9, 4.8 mos) suggesting similar populations. Network meta-analysis showed no difference between P+C and C alone in OS (HR 0.85, 95%CI 0.45-1.59, p = 0.60) or PFS (HR 0.73, 95%CI 0.48-1.1, p = 0.13), but P+C was associated with higher ORR (+16.9%, 95%CI 0.7-33%, p = 0.04). RMST analysis suggested fewer early PFS events with P+C (0-6 mo RMST ratio 1.25, RMST difference 1.02 mo, p = 0.002), with the difference disappearing at 1 year (0-12 mo RMST ratio 1.16, p = 0.07). No difference in RMST for OS was found. Overall toxicities, hematologic and grade 3-5 toxicities were higher with P+C compared with P alone (table). Conclusions: Among patients with > / = 50% PD-L1 positive NSCLC, P+C did not improve OS or PFS compared with P alone, but was associated with higher ORR. RMST analysis suggested fewer early progression events using P+C. [Table: see text]