A randomized phase II study of toripalimab consolidation or observation after concurrent chemoradiotherapy in limited-stage small cell lung cancer.

person PengXin Zhang Department of Radiation Oncology, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou, Guangdong, China info_outline PengXin Zhang, FangJie Liu, DaQuan Wang, ShiYang Zheng, JinYu Guo, YingYi Zou, Ying Liang, Yuanyuan Zhao, Bo Qiu, Hui Liu

Authors person PengXin Zhang Department of Radiation Oncology, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou, Guangdong, China info_outline PengXin Zhang, FangJie Liu, DaQuan Wang, ShiYang Zheng, JinYu Guo, YingYi Zou, Ying Liang, Yuanyuan Zhao, Bo Qiu, Hui Liu Organizations Department of Radiation Oncology, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou, Guangdong, China, Department of Radiation Oncology, State Key Laboratory of Oncology in South China, Guangdong Provincial Clinical Research Center for Cancer, Sun Yat-sen University Cancer Center, Guangzhou, Guangdong, China, Department of Radiation Oncology, Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center of Cancer Medicine, Guangzhou, China, Sun Yat-Sen University Cancer Center, Guangzhou, China, Department of Medical Oncology, Sun Yat-sen University Cancer Center, Guangzhou, China, Department of Radiation Oncology, State Key Laboratory of Oncology in South China, Guangdong Provincial Clinical Research Center for Cancer, Sun Yat-sen University Cancer Center, Guangzhou, China Abstract Disclosures Research Funding No funding sources reported Background: In recent years, the use of immune checkpoint inhibitors has led to significant progress in the treatment of extensive-stage small cell lung cancer. However, there is limited data on the efficacy of immunotherapy in patients with limited-stage disease (LS-SCLC). Therefore, we conducted a phase II randomized study to verify the efficacy and safety of Toripalimab consolidation following definitive concurrent chemoradiotherapy (CCRT) in patients with LS-SCLC (ClinicalTrials.gov ID: NCT04418648). Methods: Patients with LS-SCLC who had achieved complete or partial response after definitive CCRT (including four to six cycles of etoposide and cisplatin, and curative-intent thoracic radiotherapy) were randomly assigned (1:1) to receive Toripalimab consolidation (240mg intravenously, every 3 weeks for 6 months) or observation. Prophylactic cranial irradiation (PCI) was recommended but not mandatory. The primary endpoint was progression-free survival (PFS) calculated from randomization, and secondary endpoints included overall survival (OS) and toxicity. Results: As of data cutoff (November 30, 2023), a total of 64 eligible patients (intent-to-treat population) were randomly assigned to the Toripalimab group (n = 31) or the observation group (n = 33), respectively. With the median follow-up of 25 months, PFS was significantly improved with Toripalimab (hazard ratio [95% CI]: 0.47 [0.22-1.02]; P = 0.04). The median PFS in observation group was 12.3 months (95% CI, 0.04-24.50), while the median PFS in the Toripalimab group has not been reached. The 24-month PFS rate was 61.6% (95% CI, 43.0%-88.3%) in the Toripalimab group and 34.8% (95% CI, 21.5%-56.3%) in the observation group. The 24-month OS was 82.7% (95% CI, 65.2%-100%; P = 0.23) in the Toripalimab group and 59.1%(95% CI, 44.2%-79.1%) in the observation group. There were 5(16.1%) and 3 (9.1%) patients in the Toripalimab group and observation group experiencing G2+ pneumonitis respectively. No G4+ toxic events occurred in either group. Conclusions: Our preliminary results suggested Toripalimab consolidation following definitive CCRT was effective and tolerable in LS-SCLC. Clinical trial information: NCT04418648. Toripalimab Group (n = 31) Observation Group (n = 33) Total (n = 64) P-value Age, median(range) 62(29-71) 59(39-71) 59(29-71) 0.79 Gender, n(%) Male Female 25(80.6) 6(19.4) 28(84.8) 5(15.2) 53(82.8) 11(17.2) 0.66 ECOG, n(%) 0 1 5(16.1) 26(83.9) 7(21.2) 26(78.8) 12(18.8) 52(81.2) 0.61 Disease Stage, n(%) II III 3(9.7) 28(90.3) 3(9.1) 30(90.9) 6(9.4) 58(90.6) 0.94 Chemotherapy cycle, n(%) 4 5 6 26(83.9) 1(3.2) 4(12.9) 28(84.8) 1(3.1) 4(12.1) 54(84.4) 2(3.1) 8(12.5) 0.92 Radiation Dose, n(%) 45Gy/30f 60-65Gy/24-26f 25(80.6) 6(19.4) 24(72.7) 9(27.3) 49(76.6) 15(23.4) 0.46 PCI Yes No 25(80.6) 6(19.4) 24(72.7) 9(27.3) 49(76.6) 15(23.4) 0.46 Median cycle of Toriplimab (range) 5(1-8)

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