Surufatinib plus PD-1/L1 inhibitors as maintenance therapy following first line (1L) platinum-based chemotherapy combined with PD-1/L1 inhibitors in patients (pts) with extensive-stage small cell lung cancer (ES-SCLC).

Abstract

e15109 Background: Pts with ES-SCLC have a poor prognosis. PD-1/L1 inhibitors combined with chemotherapy as 1L treatment has been demonstrated to improve the survival. Yet, pts are prone to progression after chemo-immunotherapy followed by anti-PD-1/L1 monotherapy. A multicenter, single-arm phase II study was conducted to evaluate the efficacy and safety of surufatinib (a small-molecule inhibitor of VEGFR 1-3, FGFR1 and CSF-1R) combined with PD-1/L1 inhibitors in pts with ES-SCLC as 1L maintenance therapy. Methods: Key inclusion criteria were cytologically or pathologically confirmed ES-SCLC, ECOG PS 0-1, no disease progression after 4-6 cycles platinum-based chemotherapy combined with PD-1/L1 inhibitors. Enrolled pts received surufatinib (250mg, po, QD) plus PD-1/L1 inhibitors (same as that in prior 1L therapy: Durvalumab, Sintilimab, Toripalimab or Serplulimab) until disease progression or intolerable toxicity. The primary endpoint is progression free survival (PFS) per RECIST 1.1 by investigator. Results: From Sept 2022 to July 2023, 21 pts were enrolled. The median age was 62 years. 90.5% were male, 85.7% were former and current smokers and 52.4% had ECOG PS of 0, 11 pts completed 6 cycles of platinum-based chemotherapy combined with PD-1/L1 inhibitors, and 12 pts received durvalumab in 1L therapy. As of 20 Nov, 2023, the median follow-up duration was 9.2 months. Objective response rate (ORR) was 14.3% and DCR (disease control rate) was 71.4%. The mPFS of 1L maintenance therapy was 4.0 months (95%CI: 2.0-5.6). The mPFS from 1L treatment to disease progression was 8.7 months. mOS was not reached, with 3 mo- , 6 mo- and 9 mo- OS rate was 100%, 94.4% and 75.6%, respectively. 21 (100%) pts experienced treatment-emergent adverse events (TEAEs), and 8 (38.1%) pts experienced grade ≥3 TEAEs, most commonly with platelet count decreased, neutrophil count decreased and pneumonia. There was no treatment-related death. Conclusions: Surufatinib combined with PD-1/L1 inhibitors showed encouraging efficacy and tolerable safety profile as 1L maintenance therapy. Further OS follow-up is warranted. Clinical trial information: NCT05509699 .