摘要目的:探讨替雷利珠单抗联合化疗一线治疗局部晚期/转移性非鳞状非小细胞肺癌(NSCLC)患者的肿瘤缓解特征。方法:选取RATIONALE 304研究中替雷利珠单抗联合化疗或单独化疗治疗后经独立评审委员会评估获得完全缓解或部分缓解的非鳞状NSCLC患者，分析其缓解特征和安全性特征。至缓解时间(TTR)定义为从随机到获得首次客观缓解的时间。肿瘤缓解深度定义为与基线靶病变长径总和相比的最大肿瘤缩小百分比。结果:截至2020年1月23日，共计128例替雷利珠单抗联合化疗治疗的患者获得肿瘤客观缓解(应答者)，占意向治疗人群的57.4%(128/223)，TTR为5.1~33.3周，中位TTR为7.9周。在应答者(128例)中，50.8%(65例)在首次疗效评估(第6周)时获得首次缓解，31.3%(40例)在第2次疗效评估(第12周)时获得首次缓解，18.0%(23例)在第3次及之后的肿瘤评估中获得首次缓解。肿瘤缓解深度达到30%~<50%、50%~<70%和70%~100%的应答者比例分别为45.3%(58/128)、28.1%(36/128)和26.6%(34/128)，中位无进展生存时间(PFS)分别为9.0个月(95% CI: 7.7~9.9个月)、11.5个月(95% CI: 7.7个月~不可估计)和未达到(95% CI: 11.8个月~不可估计)。应答者整体耐受性良好，与总体安全性人群类似。 结论:替雷利珠单抗联合化疗治疗非鳞状NSCLC的应答者中，82.0%(105/128)的患者在前2次肿瘤评估(12周)内获得缓解，18.0%(23/128)的患者在更晚期(18~33周)的评估中获得缓解，且肿瘤缓解深度较深的应答者其PFS有延长趋势。

abstractsObjective:To investigate the response characteristics of patients with locally advanced/metastatic non-squamous non-small cell lung cancer (nsq-NSCLC) treated with tislelizumab in combination with chemotherapy in the first line.Methods:Patients with nsq-NSCLC who achieved complete or partial remission after treatment with tislelizumab in combination with chemotherapy or chemotherapy alone in the RATIONALE 304 study, as assessed by an independent review board, were selected to analyze the response characteristics and safety profile of the responders. Time to response (TTR) was defined as the time from randomization to the achievement of first objective response. Depth of response (DpR) was defined as the maximum percentage of tumor shrinkage compared with the sum of the baseline target lesion length diameters.Results:As of January 23, 2020, 128 patients treated with tislelizumab in combination with chemotherapy achieved objective tumor response (responders), representing 57.4%(128/223) of the intention-to-treat population, with a TTR of 5.1 to 33.3 weeks and a median TTR of 7.9 weeks. Of the responders (128), 50.8%(65) achieved first remission at the first efficacy assessment (week 6), 31.3%(40) at the second efficacy assessment (week 12), and 18.0%(23) at the third and subsequent tumor assessments. The percentages of responders who achieved a depth of tumor response of 30% to <50%, 50% to <70% and 70% to 100% were 45.3%(58/128), 28.1%(36/128) and 26.6%(34/128), respectively, with median progression-free survival (PFS) of 9.0 months (95% CI: 7.7 to 9.9 months), 11.5 months (95% CI: 7.7 months to not reached) and not reached (95% CI: 11.8 months to not estimable), respectively. Tislelizumab plus chemotherapy were generally well tolerated in responders with similar safety profile to the overall safety population. Conclusion:Among responders to tislelizumab in combination with chemotherapy for nsq-NSCLC, 82.0%(105/128) achieves response within the first two tumor assessments (12 weeks) and 18.0%(23/128) achieves response at later (18 to 33 weeks) assessments, and there is a trend toward prolonged PFS in responders with deeper tumor response.