Preliminary results of a randomized controlled, open-label, multi-center phase II study of camrelizumab combined with chemotherapy followed by concurrent chemoradiotherapy and camrelizumab consolidation therapy versus standard chemoradiotherapy as first-line treatment for limited-disease small cell lung cancer.

e20132 Background: Immune checkpoint inhibitors combined with chemotherapy have significant clinical benefits in extensive-stage small cell lung cancer (SCLC). However, for patients with limited-disease SCLC (LD-SCLC), the data on immunotherapy combined with chemoradiotherapy is insufficient. Methods: In this open-label, multi-center, phase 2 trial, we randomly 1:1 assigned patients with previously untreated LD-SCLC to receive camrelizumab combined with chemotherapy followed by concurrent chemoradiotherapy (CCRT) and camrelizumab consolidation therapy or standard chemoradiotherapy. Patients with ECOG performance status of 0 to 1, and adequate organ function were eligible. For thoracic radiation, 45 Gy in 3 weeks (1.5 Gy, BID) was given on the first day of the third cycle of chemotherapy. An etoposide plus platinum-based regimen was given 4 cycles in total. Patients who had a good response to initial treatment were offered prophylactic cranial irradiation. The primary endpoint was the 1-year progression-free survival rate. We assumed that the 1-year PFS rate in the experimental group was expected to reach 65% compared to chemoradiotherapy alone group 45%, and planned to enroll 112 patients with 56 in each group. Results: Up to date, we have enrolled 40 patients. The median follow-up was 10.6 months. Safety was evaluated in all treated patients. No Grade 5 adverse event was observed. Grade 3 or 4 treatment-related adverse events occurred in 58.8% of the patients in the camrelizumab plus chemoradiotherapy and in 52.9% of those in the chemoradiotherapy alone group. The most frequent grade 3 or 4 adverse events were hematologic toxicities (70.6% vs. 58.8%). Acute esophagitis and pneumonitis of grade 3 occurred in both groups were 1/17 (5.9%) and 1/17 (5.9%), respectively. In the experimental group, only one patient was developed grade 3 immune pneumonia 1/17 (5.9%). The 1-year PFS rate was 54.5% (95% confidence interval CI 19.5%-89.6%) with camrelizumab plus chemoradiotherapy and 44.4% (95% CI 3.9%-88.0%) with chemoradiotherapy alone. Among the 17 patients who received camrelizumab, the median PFS time was not reached, as compared with 14.35 (95% CI, 8.15-20.91) months among the 17 patients with chemoradiotherapy alone. Conclusions: In patients with LD-SCLC, the addition of camrelizumab to chemoradiotherapy did not increase the incidence of adverse events. Camrelizumab plus chemoradiotherapy resulted in an encouraging 1-year PFS rate. Larger sample sizes and longer follow-up times are required to validate our preliminary results. Clinical trial information: ChiCTR2000032275.