The primary endpoint analysis of SCARLET study: A single-arm, phase II study of sotorasib plus carboplatin-pemetrexed in patients with advanced non-squamous, non-small cell lung cancer with KRAS G12C mutation (WJOG14821L).
Shinya Sakata, Hiroaki Akamatsu, Koichi Azuma, Takehiro Uemura, Yuko Tsuchiya‐Kawano, Hiroshige Yoshioka, Mitsuo Osuga, Yasuhiro Koh, Satoshi Morita, Nobuyuki Yamamoto
Abstract
9006 Background: Efficacy and safety of sotorasib in combination with platinum-doublet chemotherapy in KRAS G12C-mutated non-squamous, non-small cell lung cancer (non-Sq, NSCLC) has not been investigated. Methods: In this single-arm, phase 2 study, chemotherapy-naïve, advanced non-Sq, NSCLC patients with KRAS G12C mutation were enrolled. Participants were treated with sotorasib 960mg, QD plus carboplatin (AUC 5)/pemetrexed 500mg/m 2 for four cycles, followed by sotorasib plus pemetrexed until disease progression. The primary endpoint was overall response rate (ORR) by independent review. The secondary endpoints were progression-free survival (PFS), overall survival (OS) and safety. Using plasma samples, next-generation sequencing analysis was done at baseline, 3 weeks and disease progression. Regarding statistical consideration, the threshold and the expected ORR were set as 40% and 65%, respectively with one-sided α = 0.1, and β = 0.1, the required sample size was 28 cases (Simon’s two-stage design). A total of 30 cases was planned to take into account the possibility of a few dropped or ineligible cases. This study was funded by AMGEN Inc. and Trial identification no. is jRCT2051210086. Results: Between Oct 2021 and Jul 2022, 30 patients were enrolled. Twenty-nine and 27 were analyzed for safety and efficacy, respectively. Of those, median age was 70, male/female: 25/5, never-/smoker: 1/29, ECOG performance status: 0/1 11/19 and PD-L1 expression level: ≥50%/1-49%/<1% 15/10/5. The primary endpoint, ORR by independent review was 88.9% (80%CI 78.5-94.8%). Median PFS was not reached mainly due to shorter follow-up period (median 4.2 months) and PFS rate at 6 months was 61.2%. OS rate at 6 months was 87.0%. Subgroup analysis revealed that ORR did not differ by PD-L1 expression level (≥50%/1-49%/<1%: 76.9%/77.8%/80.0%, respectively). Common adverse events were anemia, neutrophil count decreased, nausea and platelet count decreased. Grade≥3 AEs were mostly hematological toxicities, but one treatment-related death (pneumonia) occurred. At baseline, 70% of plasma samples were positive for KRAS G12C and most common co-occurring mutation was TP53 (50%). At 3 weeks, plasma KRAS G12C disappeared among 60% of patients. Conclusions: Sotorasib in combination with CBDCA/PEM demonstrated favorable ORR and tolerability in advanced non-Sq, NSCLC patients with KRAS G12C mutation. Clinical trial information: jRCT2051210086 .