Biomarker‐driven phase 2 umbrella trial study for patients with recurrent small cell lung cancer failing platinum‐based chemotherapy

Background A high percentage of small cell lung cancer (SCLC) cases harbor cell cycle–related gene mutations and RICTOR amplification. Based on underlying somatic mutations, the authors have conducted a phase 2 biomarker‐driven, multiarm umbrella study. Methods The SCLC Umbrella Korea StudiES (SUKSES) is an adaptive platform trial that undergoes continual modification according to the observed outcomes. This study included 286 patients with SCLC who failed platinum therapy and who had known genomic profiles based on a predesigned screening trial. Patients with MYC amplification or CDKN2A and TP53 co‐alterations were allocated to adavosertib (SUKSES protocol C [SUKSES‐C]; 7 patients) and those with RICTOR amplification were allocated to vistusertib (SUKSES‐D; 4 patients). Alternatively, patients who were without any predefined biomarkers were assigned to a non–biomarker‐selected arm: adavosertib (SUKSES‐N1; 21 patients) or AZD2811NP (SUKSES‐N3; 15 patients). Results Patients in the SUKSES‐C and SUKSES‐N1 arms demonstrated no objective response. Three patients presented with stable disease (SD) in SUKSES‐C and 6 patients in SUKSES‐N1. The median progression‐free survival (PFS) was 1.3 months (95% confidence interval, 0.9 months to not available) for SUKSES‐C and 1.2 months (95% CI, 1.1‐1.4 months) for SUKSES‐N1. Patients in the SUKSES‐D arm demonstrated no objective response and no SD, with a PFS of 1.2 months (95% CI, 1.0 months to not available). The SUKSES‐N3 arm had 5 patients with SD and a PFS of 1.6 months (95% CI, 0.9‐1.7 months), without an objective response. Grade≥3 adverse events (graded according to National Cancer Institute Common Terminology Criteria for Adverse Events [version 4.03]) were observed as follows: 3.2% in the SUKSES‐C and SUKSES‐N1 arms and 50.0% in the SUKSES‐D arm. Target‐related neutropenia (grade≥3) was observed in approximately 60.0% of patients in the AZD2811NP arm using the current dosing schedule. Conclusions To the best of the authors' knowledge, the current study is the first biomarker‐driven umbrella study conducted in patients with recurrent SCLC. Although the current study demonstrated the limited clinical efficacy of monotherapy, novel biomarker approaches using other cell cycle inhibitor(s) or combinations warrant further investigation.