194MO Phase II study of low-dose radiation (LDRT) plus durvalumab (D) and etoposide/platinum (EP) as first-line treatment in ES-SCLC (LEAD): Efficacy and safety results
Yuwen Zhang, Yun Xie, Youling Gong, Meijuan Huang, J. Li, Li Zhang, Xiaojuan Zhou, Yu‐Shiuan Wang, Bingwen Zou, Yiqiong Liu, Feng Peng, Min Yu, Weigang Xiu, Y. Li, Yongjiang Yu, Shan Zeng, L. Xiang, Zhi Yao, Jianxin Xue, You Lü
Abstract
The phase III CASPIAN trial established D+ EP as first-line (1L) standard of care of ES-SCLC. However, most patients (pts) do not experience durable clinical benefit. LDRT could induce local control, and exert synergistic efficacy with Immune checkpoint inhibitors. In the LEAD study we investigated LDRT plus D and EP as 1L treatment of ES-SCLC pts. LEAD study was a single arm, multicenter, phase II trial. Treatment-naïve ES-SCLC pts aged ≥18 with ECOG PS 0-1 were eligible. D 1500 mg + EP was administered Q3W for 4 cycles, followed by D maintenance. Concurrent LDRT (15 Gy/5 fractions) were conducted in the first cycle. Prophylactic cranial radiation (PCI) was allowed per investigator discretion. The primary endpoint was progression-free survival (PFS). Secondary endpoints included overall survival (OS) and safety. From Mar. 2022 to Feb. 2023, 30 eligible pts were enrolled from 4 sites in China. At data cut-off (Nov. 9th 2023), the median age was 58 years (range 40-77); 97% (29 ) pts were male. 60% (17) pts had ECOG PS of 1. Presence of liver and brain metastases at baseline were reported in 20% (6) and 10% (3) pts, respectively. 57% (17) pts underwent PCI. Median follow up for PFS in censored pts was 17.3 months (mo), PFS events occurred in 73% (22) pts. mPFS was 8.3 mo [95% CI 4.6-15.2], 6-mo and 12-mo PFS rates were 57% and 40%, respectively. mOS was not reached [95% CI 10.8m-NE]. Overall objective response rate (ORR) was 87%. Among pts with liver and brain metastases, ORR was 50% and 100% respectively. Grade (G) ≥ 3 treatment emergent adverse event (TEAE) occurred in 80% (24) pts, the most common G ≥ 3 TEAEs were hematological toxicity. G ≥ 3 immune-related AEs (irAEs) were reported in 13.3% (4) pts. Incidence of radiation-related SAEs was 16.7% (5). Interstitial lung disease occurred in 1 pt (G2). 33.3% (10) pts were still on treatment at data cut-off, further assessment is ongoing. Concurrent LDRT and D+ EP demonstrated promising prolonged mPFS in 1L ES-SCLC and was well-tolerated in LEAD study. This result warrant further investigation of this treatment modality in ES-SCLC.