肿瘤内异质性（ITH）已与接受免疫检查点阻断（ICB）治疗的晚期非小细胞癌（NSCLC）患者的预后不良相关。然而，目前没有证据支持ITH度量作为ICB临床受益的预测因子。血液的独特优势使其成为ITH估计和相关应用的有希望的材料。本研究旨在开发和验证基于血液的ITH指数，预测ICB反应。OAK和POPLAR临床试验的NSCLC患者被用作算法开发的训练队列。采用总生存期（OS）和无进展生存期（PFS）为终点的生存分析用于评估临床反应。随后，利用42名接受PD-1阻断治疗的NSCLC患者的独立队列验证bITH的预测价值。bITH与OAK患者中用atezolizumab与docetaxel产生的差异OS和PFS显著相关，无论是单变量还是多变量分析，这表明bITH是ICB反应的独立预测因子。此外，与血液肿瘤突变负荷（bTMB）相比，bITH实现了更大的OS分化和可比的PFS分化，并且无论bTMB状态如何，都具有预测作用。此外，bITH和PFS之间的关联得到了独立队列的验证。ITH度量低的患者在免疫疗法与化疗中表现出显着的OS和PFS受益。期待未来的研究来证实我们的发现，并丰富ITH的临床实用性。本研究得到了中国国家自然科学基金（Nos. 81972718和81572321），浙江省自然科学基金（No. LY19H160007），浙江省卫生与医学科技计划（No. 2021KY541），四川省科技厅科研项目（No. 21YYJC1616），四川省医学会科研项目（No. S20002），吴杰平医学基金会（No. 320.6750）和2022年广州黄埔区和广州开发区的创业领军人才（No. 2022-L023）的支持。版权所有©2023 Elsevier B.V.

Intratumor heterogeneity (ITH) has been associated with poor prognosis in advanced non-small cell cancer (NSCLC) patients receiving immune checkpoint blockade (ICB) therapies. However, there is currently no evidence supporting an ITH metric as a predictor of clinical benefit from ICB. The unique advantages of blood make it a promising material for ITH estimation and relevant applications. This study aims to develop and validate a blood-based ITH index for predicting ICB response.NSCLC patients from the OAK and POPLAR clinical trials were used as the training cohorts for algorithm development. Survival analyses with overall survival (OS) and progression-free survival (PFS) as endpoints were performed to assess clinical response. The predictive value of bITH was subsequently validated with an independent cohort of 42 NSCLC patients treated with PD-1 blockade.bITH was significantly associated with the differential OS and PFS elicited by atezolizumab vs. docetaxel in both univariable and multivariable analyses in the OAK patients, suggesting bITH as an independent predictor for response to ICB. Moreover, compared with blood tumor mutation burden (bTMB), bITH enabled greater OS segregation and comparable PFS segregation, and obtained a predictive role regardless of bTMB status. Moreover, the association between bITH and PFS was validated with an independent cohort.Patients with low blood-based ITH metric manifest significant OS and PFS benefit from immunotherapy versus chemotherapy. Future research is awaited to corroborate our findings and to enrich the clinical utility of ITH.This study was supported by the National Natural Science Foundation of China (Nos. 81972718 and 81572321), the Natural Scientific Foundation of Zhejiang Province, China (No. LY19H160007), the Science and Technology Program for Health and Medicine in Zhejiang Province, China (No. 2021KY541), the Scientific Research Project, Science and Technology Department of Sichuan Province (No. 21YYJC1616), the Scientific Research Project, Sichuan Medical Association (No. S20002), Wu Jieping Medical Foundation (No. 320.6750), and 2018 Entrepreneurial Leading Talent of Guangzhou Huangpu District and Guangzhou Development District (No. 2022-L023).Copyright © 2023. Published by Elsevier B.V.