Asian Subgroup Analysis of Patients in the Phase 2 DeLLphi-301 Study of Tarlatamab for Previously Treated Small Cell Lung Cancer

Introduction: Tarlatamab is a bispecific T-cell engager (BiTE®) immunotherapy that binds delta-like ligand 3 on the surface of small cell lung cancer (SCLC) cells and CD3 on T cells, facilitating T cell-mediated cancer cell lysis. In the primary analysis of the phase 2 DeLLphi-301 study (NCT05060016), tarlatamab showed a favourable benefit-to-risk profile with durable objective responses and promising survival outcomes in patients with previously treated SCLC. Here, phase 2 data for the Asia region subgroup are presented.
Methods: Patients with previously treated, advanced SCLC received 10 mg tarlatamab every 2 weeks. The primary endpoint was objective response rate (ORR) by blinded independent central review (RECIST version 1.1). Key secondary endpoints included duration of response (DOR), progression-free survival (PFS), overall survival (OS) and safety. The present analysis includes patients enrolled at sites in Asia.
Results: A total of 43 patients were enrolled at sites in Asia. ORR was 46.3% (95% confidence interval [CI], 30.7–62.6) and median DOR was 7.2 months (95% CI 3.9 to not estimable). The median follow-up was 16.6 months for PFS and 21.2 months for OS. Median PFS was 5.4 months (95% CI 3.0–8.1) and median OS was 19.0 months (95% CI 11.4 to not estimable). The most common treatment-emergent adverse event (AE) was cytokine release syndrome (48.8%), and all such events were grade 1 or 2. There were no discontinuations due to treatment-related AEs.
Conclusions: Tarlatamab demonstrated durable responses and promising survival outcomes with a manageable safety profile in this post hoc analysis of patients from Asia with previously treated SCLC.
Trial Registration: ClinicalTrials.gov, NCT05060016.