Efficacy and safety of surufatinib plus PD-1/PD-L1 inhibitors as first-line maintenance therapy in extensive-stage small cell lung cancer

Abstract Purpose Patients with extensive-stage small cell lung cancer (ES-SCLC) have poor prognosis. This phase 2 study evaluated the efficacy and safety of surufatinib plus programmed death-1 (PD-1)/programmed death ligand 1 (PD-L1) inhibitors as maintenance therapy in patients with ES-SCLC without disease progression after first-line chemoimmunotherapy. Methods Patients with ES-SCLC and with non-progressive disease after 4–6 cycles of platinum-based chemotherapy plus PD-1/PD-L1 inhibitors received oral surufatinib 250 mg once daily plus PD-1/PD-L1 therapy. The primary endpoint was progression-free survival (PFS) assessed by investigators. Results A total of 21 patients (71.4% aged under 65 years; 61.9% with 5–6 induction cycles) were enrolled between 19 September 2022 and 30 June 2023 and received ≥ 1 study treatment. The median PFS was 4.0 months (95% CI: 1.9–6.4) from maintenance therapy initiation and 8.8 months (95% CI: 6.5–13.4) from induction therapy initiation. From initiation of maintenance treatment, median overall survival (OS) was not reached after 17.1 months of follow-up and the 18-month OS was 57.1% (95% CI: 33.8–74.9). Among 13 patients with measurable lesions at baseline, the objective response rate was 23.1% (95% CI: 5.0–53.8), and disease control rate was 53.8% (95% CI: 25.1–80.8). Treatment-related adverse events (TRAEs) occurred in 19 patients (90.5%), with grade ≥ 3 TRAEs reported in six patients (28.6%). Two patients (9.5%) discontinued due to TRAEs; no treatment-related deaths occurred. Conclusions Surufatinib combined with PD-1/PD-L1 inhibitors as first-line maintenance therapy showed encouraging PFS and a tolerable safety profile in patients with ES-SCLC who received chemotherapy combined with PD-1/PD-L1 inhibitors as first-line induction therapy. Trial registration ClinicalTrials.gov, NCT05509699. Registered 16 August 2022, https//clinicaltrials.gov/study/NCT05509699.