A randomized, multicentre, phase II trial reports signals of improved progression-free survival (PFS) and overall survival (OS) with toripalimab consolidation after concurrent chemoradiotherapy (cCRT) in Chinese patients with limited-stage (LS) small-cell lung cancer (SCLC).
The benefit of adding immune checkpoint inhibitors (ICIs) to chemotherapy has so far been established in extensive-stage SCLC for three agents, namely, atezolizumab, durvalumab, and toripalimab. [N Engl J Med 2018;379:2220-2229; Lancet 2019;394:1929-1939; JAMA Oncol 2025;11:16-25] In LS-SCLC, only durvalumab has shown efficacy to date – specifically, as consolidation therapy among patients who did not progress after definitive cCRT, in the phase III ADRIATIC trial. [N Engl J Med 2024;391:1313-27]
“The present [GASTO-1052A] trial was designed to evaluate the efficacy and safety of toripalimab as consolidation therapy in patients with LS-SCLC without disease progression after cCRT – a paradigm aligned with the positive ADRIATIC trial,” stated the researchers. [J Immunother Cancer 2026;14:e016467]
A total of 98 patients (median age, 60 years; male, 85.7 percent) were randomized to receive either toripalimab consolidation (240 mg Q3W for up to 6 months; n=49) or observation (n=49) after cCRT at three hospitals in China between June 2020 and May 2024. The trial was prematurely terminated in view of the interim results of the ADRIATIC trial, which led to the recommendation of durvalumab consolidation in LS-SCLC in the National Comprehensive Cancer Network (NCCN) guidelines. [NCCN Guidelines for Small Cell Lung Cancer, version 2.2025]
At a median follow-up of 30.8 months, the median PFS was not reached (NR) in the toripalimab group vs 14.1 months in the observation group (hazard ratio [HR], 0.55; 95 percent confidence interval [CI], 0.31–0.96; p=0.035). The respective PFS rates at 24 months were 57.0 and 36.2 percent.
The OS was NR vs 30.3 months with toripalimab vs observation (HR, 0.39; 95 percent CI, 0.19–0.80; p=0.010). The estimated 24-month OS rates were 79.2 and 59.1 percent, respectively.
Failure-pattern analysis revealed that all distant relapses in the toripalimab group were oligo-organ failures, without any multiorgan metastases, which were present in the observation group. An exploratory analysis reported a median PFS2 of 14.6 months with toripalimab vs 7.2 months in the observation group. The estimated 12-month PFS2 rates were 52.9 and 27.5 percent, respectively. “These findings suggest that consolidative toripalimab not only delays relapse, but may also modulate tumour biology towards a less aggressive pattern of failure,” noted the researchers.
Grade 3–4 adverse events (AEs) occurred in 6.3 percent of patients receiving toripalimab vs 2.0 percent of patients in the observation group. Immune-mediated AEs were reported in 22.9 percent of patients in the toripalimab group. AEs leading to discontinuation of toripalimab occurred in 12.5 percent of patients, and included pneumonitis and grade 3 fatigue. No treatment-related deaths occurred in either group.
Pneumonitis occurred in 33.3 and 24.5 percent of patients on toripalimab and observation, with grade 3–4 events reported in 4.2 and 2.0 percent, respectively. The median time to onset of pneumonitis was 1.5 and 1.2 months, respectively.
“In this exploratory analysis of a prematurely terminated trial, toripalimab showed encouraging signals of PFS and OS benefits, with an acceptable safety profile. These hypothesis-generating findings warrant confirmation in larger trials,” concluded the researchers.