310P - Final overall survival (OS) of surufatinib plus PD-1/PD-L1 antibodies as maintenance therapy following first line (1L) platinum-based chemotherapy (Chemo) plus PD-1/PD-L1 antibodies in patients (pts) with extensive-stage small cell lung cancer (ES-SCLC)

Background

Currently, the standard 1L treatment for pts with ES-SCLC is immunotherapy (IO) plus chemo, providing an initially robust response but lacking durability. This unmet medical need prompted exploration of novel maintenance therapies following the 1L treatment. A multicentre, open-label, phase II study (NCT05509699) evaluated the efficacy and safety of surufatinib plus IO as a maintenance therapy following 1L standard of care in pts with ES-SCLC.

Methods

A total of 21 pts with cytologically or pathologically confirmed ES-SCLC, without disease progression (PD) after for 4 to 6 cycles (21-day a cycle) of 1L therapy, were enrolled in the single arm phase IIa part to receive surufatinib (250 mg, orally, once daily) plus PD-1/PD-L1 antibodies (durvalumab, sintilimab, toripalimab, or serplulimab), until PD or intolerable toxicity. The maximum IO duration were 24 months (m). The efficacy and safety data have been previously reported. Herein, the final OS data are presented. Exploratory subgroup analyses of prognostic factors potentially impacting OS were also performed.

Results

As of Jul 31, 2024, the majority of pts (81.0% [17/21]) had discontinued study treatments, primarily due to PD (71.4% [15/21]), while four pts remained on treatment, and nine died. The median follow-up duration was 17.1 m for maintenance and 22.5 m for 1L (induction + maintenance) therapy. The OS rates for maintenance therapy at 12- and 18-m were both 57.1%; for 1L therapy at 12- and 18-m were 85.7% and 57.1%, respectively. Subgroup results of OS rate at 18-m for 1L- and at 15-m for maintenance therapy are provided.

Subgroup analysis of OS