针对免疫治疗反应的非侵入性生物标志物仍然是一个迫切的未满足的医学需求。POLARIS-03是一个多中心II期临床试验，评估了托瑞帕利单抗（抗程序性细胞死亡1）治疗难治性转移性尿路上皮癌（mUC）的安全性和有效性。我们从单机构生物标志物队列中评估了纵向循环肿瘤DNA（ctDNA）分析的预测效力。共有27例接受托瑞帕利单抗（3 mg/kg Q2W）治疗的mUC患者在人民医院接受了登记。在治疗开始时和每两个疗程后采集了连续的血浆标本。我们采用了600基因面板（PredicineATLAS™）液体活检检测来探测体细胞变异和癌细胞分数（CCF）。采用低通全基因组测序来确定拷贝数异常（CNA）评分。在整个队列中，我们观察到ctDNA检测到的体细胞异常和配对肿瘤样本推断出的异常存在不同程度的一致性。尽管基线CCF或CNA的预测价值有限，但第8周的早期ctDNA反应与托瑞帕利单抗的疗效和患者生存时间有关。结合CCF和CNA减少可实现对响应者和非响应者的分类准确率达90.5%，并预测托瑞帕利单抗的长期效益。血液中CCF和CNA的动态变化精确反映了恶性病变的影像评估，包括FGFR3-TACC3基因融合或微卫星不稳定性。该研究证明了整合纵向ctDNA分析作为潜在生物标志物在接受免疫治疗的mUC患者中的可行性和有效性，并支持进一步对最小创伤液体活检检测方法进行治疗分层和监测的临床评估。©2023英国和爱尔兰病理学会。

Non-invasive biomarkers for immunotherapy response remain a compelling unmet medical need. POLARIS-03 is a multicenter phase II trial to evaluate the safety and efficacy of toripalimab (anti-programmed cell death 1) in refractory metastatic urothelial carcinoma (mUC). We assessed the predictive utility of longitudinal circulating tumor DNA (ctDNA) analysis from a single-institution biomarker cohort. Twenty-seven mUC patients receiving toripalimab (3 mg/kg Q2W) at Ren Ji Hospital were enrolled. Serial plasma specimens were obtained at baseline and then every two cycles during treatment. The 600-gene panel (PredicineATLAS™) liquid biopsy assay was applied to probe somatic variants and cancer cell fraction (CCF). Low-pass whole genome sequencing was used to determine the copy number abnormality (CNA) score. Across the entire cohort, we observed different degrees of concordance between somatic aberrations detected by ctDNA and those inferred by matched tumor samples. Although the baseline CCF or CNA had limited predictive value, early ctDNA response at week 8 was associated with toripalimab efficacy and prolonged patient survival. Integrating CCF and CNA decrease achieved a superior accuracy of 90.5% in classifying responders and non-responders and predicted long-term benefit from toripalimab. Dynamic changes in the CCF and CNA in blood exquisitely reflected radiographic assessment of malignant lesions, including those with FGFR3-TACC3 gene fusion or microsatellite instability. This study demonstrates the feasibility and effectiveness of integrated longitudinal ctDNA profiling as a potential biomarker in mUC patients undergoing immunotherapy and supports further clinical evaluation of minimally invasive liquid biopsy assays for treatment stratification and therapy monitoring. © 2023 The Pathological Society of Great Britain and Ireland.© 2023 The Pathological Society of Great Britain and Ireland.