193 - Durvalumab Combined with Concurrent Chemoradiotherapy in Patients with Limited-Stage Small-Cell Lung Cancer: A Prospective, Single-Arm, Phase II Clinical Trial

W. B. Shen¹, C. Song², and H. Wang³; ¹Radiotherapy Department,the Fourth Hospital of Hebei Medical University, shijiazhuang, hebei, China, ²Radiotherapy Department,the Fourth Hospital of Hebei Medical University, Shijiazhuang, hebei, China, ³Radiotherapy Department,The Fourth Hospital of Hebei Medical University, shijiazhuang, hebei, China

Purpose/Objective(s): The current standard treatment for limited-stage small-cell lung cancer (LS-SCLC) is induced chemotherapy followed by concurrent chemoradiotherapy (CCRT). This clinical trial is designed to investigate the efficacy and safety using durvalumab with chemoradiotherapy for LS-SCLC. Materials/

Methods: In this single-arm phase II study, patients who had cytologically or histologically confirmed LS-SCLC received 3 cycles of etoposide, cisplatin or carboplatin, and durvalumab every 3 weeks, following by thoracic radiotherapy of 60.0 Gy in 30 once-daily fractions and chemoimmunotherapy. After CCRT plus durvalumab (given as four to six cycles of chemotherapy in both groups), patients received durvalumab consolidation therapy every 3 weeks for a minimum of 1 year. Prophylactic cranial irradiation (PCI) was recommended to patients with partial or complete response when chemoradiotherapy completed. The once-daily radiotherapy group in CONVERT trial was taken as historical control group. The 2-year OS rate of the historical control group was 51% (H0). We hypothesized that adding experimental therapy, durvalumab, to the current standard scheme could increase the 2-year OS rate to 66% (H1). The primary end point was overall survival (OS). Efficacy and adverse events were assessed.
Results: Overall, 43 patients were enrolled from April 1, 2020 to April 1, 2023 with the median follow-up duration of 34.0 months. The 1, 2, 3-year progression-free survival (PFS) were 54.9%, 36.6%, 30.4%, respectively, and median PFS was 15.8 months (95% con?dence interval: 9.2-22.4). The 1, 2, 3-year local progression-free survival (LPFS) were 82.4%, 69.6%, 65.3%, respectively, and median LPFS was not reached. The 1, 2, 3-year distant metastasis-free survival (DMFS) were 63.9%, 52.0%, 44.1%, respectively, and median DMFS was 25.3 months (95% con?dence interval: 14.0-36.6). The 1, 2, 3-year OS were 87.7%, 67.1%, 49.1%, respectively, and median OS was 32.0 months. Among the 40 patients who were candidates for PCI, the PCI group (n=20) had signi?cantly fewer events of brain metastasis (10.0% vs 55.0%, p=0.007) and better survival (?²=3.881, p=0.049) compared to the no PCI group (n=20). There were 14 (32.6%) patients with grade 3 or 4 adverse events in which 5 patients were immune-related.
Conclusion: Our results suggest that the addition of durvalumab to chemoradiotherapy was well tolerated and highly effective in comparison with prior reports (CONVERT trial) of chemoradiotherapy-only regimens, supporting further investigation in patients with LS-SCLC eligible for radical chemoradiotherapy.