LBA13 Dostarlimab + Chemotherapy (CT) Vs Pembrolizumab + CT in Metastatic Non-Squamous Non-Small Cell Lung Cancer (NSCLC): Updated Asian Subgroup Analyses of the PERLA Trial

PERLA (NCT04581824) is the first global head-to-head study of two programmed cell death protein (ligand)-1 (PD-[L]1) inhibitors in NSCLC. This randomized phase II double-blind study compares the efficacy and safety of dostarlimab (dostar) + CT vs pembrolizumab (pembro) + CT as first-line (1L) treatment in patients (pts) with metastatic non-squamous NSCLC; similar efficacy and safety between groups have been demonstrated [1]. Asian countries were well represented in PERLA. Here we report overall survival (OS) for the Asian population. Pts with known PD-L1 status, absence of EGFR, ALK or other actionable genomic aberrations determined locally, ECOG 0–1, and no prior systemic treatment were randomized 1:1 to dostar 500 mg or pembro 200 mg Q3W IV ≤35 cycles, both combined with CT (4 cycles pemetrexed [pem] 500 mg/m2 + carboplatin AUC 5 mg/mL/min or cisplatin 75 mg/m2 followed by pem ≤35 cycles) Q3W IV. The primary endpoint was overall response rate (ORR) by blinded independent central review (BICR). Secondary endpoint was OS, determined by Kaplan-Meier (KM) method; 95% confidence intervals by Brookmeyer-Crowley method and hazard ratio by stratified Cox proportional hazard model. At data cut off (7Jul2023) 243 pts were randomized and treated in PERLA. The Asian population was the third largest (44 pts; 23 in dostar + CT and 21 in pembro + CT). Median OS in the Asian subgroup was not reached in the dostar + CT arm and 15.9 months (mo) in the pembro + CT arm (Table) after median follow up (IQR) of 25.4 (22.3, 28.3) and 25.8 (23.2, 26.8) mo, respectively (calculated via reverse KM estimate). ORR is shown in the table.Table: LBA13Dostar+CT (N=23)Pembro+CT (N=21)OS events (death), n (%)11 (48)14 (67)Median OS (95% CI)*, moNR (8.1, NR)15.9 (4.9, 24.5)Hazard Ratio (95% CI)†0.66 (0.29, 1.50)ORR‡, % (95% CI)§CR, n (%)PR, n (%)43 (23.2, 65.5)010 (43)29 (11.3, 52.2)1 (5)5 (24)Difference in ORR, % (80% CI)¶13.82 (−5.62, 33.26)*Brookmeyer-Crowley method; †based on profile-likelihood confidence limits; ‡confirmed by BICR per RECIST v1.1; §Clopper-Pearson method; ¶Mantel-Haenszel methodCI, confidence interval; CR, complete response; NR, not reached; PR, partial response; RECIST v1.1, Response Evaluation Criteria in Solid Tumors version 1.1 Open table in a new tab *Brookmeyer-Crowley method; †based on profile-likelihood confidence limits; ‡confirmed by BICR per RECIST v1.1; §Clopper-Pearson method; ¶Mantel-Haenszel method CI, confidence interval; CR, complete response; NR, not reached; PR, partial response; RECIST v1.1, Response Evaluation Criteria in Solid Tumors version 1.1 In this follow up analysis, dostar + CT showed comparable efficacy to pembro + CT in the Asian subgroup of pts with 1L metastatic non-squamous NSCLC.