Toripalimab Consolidation Improves Survival in Limited-Stage SCLC

Toripalimab-tpzi (Loqtorzi) consolidation following chemoradiotherapy improved overall survival (OS) and progression-free survival (PFS) outcomes among patients with limited-stage small cell lung cancer (LS-SCLC), according to findings from the phase 2 GASTO-1052A trial (NCT04212052) presented at the IASLC 2025 World Conference on Lung Cancer (WCLC).¹

Topline efficacy data revealed that among patients who underwent treatment with toripalimab (n = 49) vs those who underwent observation following chemoradiation (n = 49), the median OS was not reached (NR) vs 30.3 months, respectively (HR, 0.41; 95% CI, 0.20-0.82; P = .012). Additionally, the 12- and 24-month rates were 93.7% vs 77.2% and 79.2% vs 59.1%. A subgroup analysis of OS revealed that patients who did not receive prior prophylactic cranial irradiation (PCI; HR, 0.17), those younger than 60 (HR, 0.18), those with an ECOG performance status of 1 (HR, 0.39), and those with stage III disease (HR, 0.40) experienced particular benefit with toripalimab consolidation.

Regarding median PFS, it was NR in the consolidation group vs 14.1 months (95% CI, 2.8-25.4) with observation (HR, 0.54; 95% CI, 0.31-0.94; P = .03). The respective 12- and 24-month values were 67.3% vs 50.7% and 57.0% vs 36.2%. A subgroup analysis for PFS revealed that patients who did not receive prior PCI (HR, 0.30), those younger than 60 (HR, 0.27), those with an ECOG performance status of 1 (HR, 0.47), and those with stage III disease (HR, 0.50) experienced particular benefit with toripalimab consolidation.

“Toripalimab consolidation post-[chemoradiotherapy] in patients with LS-SCLC significantly improved PFS and OS. The conditional power is 94.95% and the predictive power is 86.30% to detect a true HR of 0.548 at the final analysis,” study author PengXin Zhang, MD, of the Department of Radiation Oncology of Sun Yat-sen University Cancer Center in Guangzhou, China, wrote in the presentation with coinvestigators.¹ “Toripalimab appears to potentially decrease brain metastasis progression among patients ineligible for PCI.”

Investigators in the phase 2 trial enrolled patients with unresectable LS-SCLC without disease progression following chemoradiotherapy and randomly assigned them 1:1 to undergo treatment with toripalimab consolidative therapy or observation. Patients were stratified by disease stage I/II or III and receipt of PCI. Toripalimab consisted of 240 mg every 3 weeks for a maximum of 6 months.

Additionally, chemotherapy with etoposide and cisplatin was dosed for 4 cycles, and radiation therapy consisted of 60 to 65 Gy over 24 to 26 fractions daily for 5 to 6 weeks. If eligible, patients received PCI within 6 weeks of the last chemoradiation dose and within 42 days of the first dose of toripalimab.

The median age in the consolidative and observation groups was 60 years (range, 29-79) and 60 years (range, 39-71), respectively. Patients were mostly male (both 85.7%), had an ECOG performance status of 1 (77.6% vs 79.6%), and had a history of smoking (89.8% vs 93.9%). A similar number of patients had stage III disease (both 91.8%) and received prior PCI (both 65.3%).

The primary end point of the study was PFS. Secondary end points included OS, objective response rate, and safety.

Of note, the randomized, controlled phase 2 GASTO-1052A trial was suspended following the publication of the phase 3 ADRIATIC trial (NCT03703297) results. Results from ADRIATIC were presented at the 2024 European Society for Medical Oncology Congress (ESMO).² The results supported the FDA approval of durvalumab in patients with LS-SCLCwho have not progressed following concurrent platinum-based chemoradiation in December 2024.³

References

1. Zhang P, Wang D, He W, et al. Toripalimab consolidation after chemoradiotherapy in limited-stage small cell lung cancer: a phase II, randomized controlled study (GASTO-1052A). Presented at the International Association for the Study of Lung Cancer World Conference on Lung Cancer 2025; September 6-9, 2025; Barcelona, Spain. Abstract 3956
2. Senan S, Spigel D, Cho BC, et al. Durvalumab as consolidation therapy in limited-stage SCLC (LS-SCLC): outcomes by prior concurrent chemoradiotherapy (cCRT) regimen and prophylactic cranial irradiation (PCI) use in the ADRIATIC trial. Presented at the 2024 European Society for Medical Oncology Congress (ESMO); September 13-17, 2024; Barcelona, Spain. LBA81
3. FDA approves durvalumab for limited-stage small cell lung cancer. News release. FDA. December 4, 2024. Accessed September 15, 2025. https://shorturl.at/0eID1