Objective: The aim of this study was to assess the efficacy of maintenance pembrolizumab in patients with extensive‐stage SCLC after treatment with platinum and etoposide. Methods: Patients with extensive‐stage SCLC with a response or stable disease after induction chemotherapy were eligible. Pembrolizumab at a dose of 200 mg administered intravenously every 3 weeks was initiated within 8 weeks of the last cycle of chemotherapy. The primary end point of the study was progression‐free survival (PFS) from study registration, with overall survival (OS) as a key secondary end point. Available tumor tissue was assessed for expression of programmed death ligand 1 (PD‐L1) both in the tumor cells and in the surrounding stroma. Blood for circulating tumor cells was collected before the first, second, and third cycles of pembrolizumab. Results: Of the 45 patients enrolled, 56% were male and 22% had treated brain metastases. The median PFS was 1.4 months (95% confidence interval [CI]: 1.3–2.8), with a 1‐year PFS of 13%. The median OS was 9.6 months (95% CI: 7.0–12), with a 1‐year OS of 37%. Of the 30 tumors that could be assessed, three had PD‐L1 expression (≥1%) in the tumor cells. A total of 20 tumors could be assessed for PD‐L1 expression in the stroma. The median PFS in the eight patients with tumors positive for expression of PD‐L1 at the stromal interface was 6.5 months (95% CI: 1.1–12.8) compared with 1.3 months (95% CI: 0.6–2.5) in 12 patients with tumors negative for this marker. No unexpected toxicities were observed. Conclusion: Maintenance pembrolizumab did not appear to improve median PFS compared with the historical data. However, the 1‐year PFS rate of 13% and OS rate of 37% suggest that a subset of patients did benefit from pembrolizumab.

中文翻译：

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帕博利珠单抗维持治疗广泛期小细胞肺癌 (SCLC) 患者的 II 期研究

目的：本研究的目的是评估帕博利珠单抗维持治疗对铂类和依托泊苷治疗后广泛期 SCLC 患者的疗效。方法：诱导化疗后缓解或病情稳定的广泛期 SCLC 患者符合条件。在最后一个化疗周期的 8 周内开始每 3 周静脉注射 200 mg 的派姆单抗。该研究的主要终点是研究注册的无进展生存期 (PFS)，总生存期 (OS) 是关键的次要终点。评估可用肿瘤组织在肿瘤细胞和周围基质中的程序性死亡配体 1 (PD-L1) 的表达。在 pembrolizumab 的第一、第二和第三周期之前收集循环肿瘤细胞的血液。结果：在入选的 45 名患者中，56% 为男性，22% 接受过脑转移治疗。中位 PFS 为 1.4 个月（95% 置信区间 [CI]：1.3-2.8），1 年 PFS 为 13%。中位 OS 为 9.6 个月（95% CI：7.0-12），1 年 OS 为 37%。在可以评估的 30 个肿瘤中，三个在肿瘤细胞中具有 PD-L1 表达（≥1%）。总共可以评估 20 个肿瘤的基质中的 PD-L1 表达。8 名间质界面 PD-L1 表达阳性的肿瘤患者的中位 PFS 为 6.5 个月（95% CI：1.1-12.8），而 12 名肿瘤患者的中位 PFS 为 1.3 个月（95% CI：0.6-2.5）此标记为阴性。没有观察到意外的毒性。结论：与历史数据相比，维持派姆单抗似乎并未改善中位 PFS。然而，