Immune checkpoint blockers (ICBs)-based immunotherapy has revolutionised oncology. However, the benefits of ICBs are limited to only a subset of patients. Herein, the biomarkers-driven application of ICBs promises to increase their efficacy. Such biomarkers include lymphocytic IFNγ-signalling and/or cytolytic activity (granzymes and perforin-1) footprints, whose levels in pre-treatment tumours can predict favourable patient survival following ICB-treatment. However, it is not clear whether such biomarkers have the same value in predicting survival of patients receiving first-line anti-CTLA4 ICB-therapy, and subsequently anti-PD1 ICB-therapy (i.e., sequential ICB-immunotherapy regimen). To address this, we applied highly integrated systems/computational immunology approaches to existing melanoma bulk-tumour transcriptomic and single-cell (sc)RNAseq data originating from immuno-oncology clinical studies applying ICB-treatment. Interestingly, we observed that CD8⁺/CD4⁺T cell-associated IFNγ-signalling or cytolytic activity signatures fail to predict tumour response in patients treated with anti-CTLA4 ICB-therapy as a first-line and anti-PD1 ICB-therapy in the second-line setting. On the contrary, signatures associated with early memory CD8⁺/CD4⁺T cells (integrating TCF1-driven stem-like transcriptional programme), capable of resisting cell death/apoptosis, better predicted objective response rates to ICB-immunotherapy, and favourable survival in the setting of sequential ICB-immunotherapy. These observations suggest that sequencing of ICB-therapy might have a specific impact on the T cell-repertoire and may influence the predictive value of tumoural immune biomarkers.

基于免疫检查点阻滞剂 (ICB) 的免疫疗法彻底改变了肿瘤学。然而，ICB 的益处仅限于一部分患者。在此，生物标志物驱动的 ICB 应用有望提高其疗效。此类生物标志物包括淋巴细胞 IFNγ 信号和/或细胞溶解活性（颗粒酶和穿孔素-1）足迹，其在治疗前肿瘤中的水平可以预测 ICB 治疗后有利的患者存活率。然而，尚不清楚这些生物标志物在预测接受一线抗 CTLA4 ICB 治疗和随后的抗 PD1 ICB 治疗（即序贯 ICB 免疫治疗方案）的患者的生存方面是否具有相同的价值。为了解决这个问题，我们将高度集成的系统/计算免疫学方法应用于现有的黑色素瘤大块肿瘤转录组学和单细胞 (sc) RNAseq 数据，这些数据源自应用 ICB 治疗的免疫肿瘤学临床研究。有趣的是，我们观察到 CD8⁺ /CD4 ⁺ T 细胞相关的 IFNγ 信号或细胞溶解活性特征无法预测接受抗 CTLA4 ICB 治疗作为一线治疗和抗 PD1 ICB 治疗作为二线治疗的患者的肿瘤反应。相反，与早期记忆 CD8 ⁺ /CD4 ⁺ T 细胞（整合 TCF1 驱动的干细胞样转录程序）相关的特征能够抵抗细胞死亡/细胞凋亡，更好地预测对 ICB 免疫疗法的客观反应率，以及有利的存活率序贯 ICB 免疫疗法的设置。这些观察结果表明，ICB 治疗的顺序可能对 T 细胞库产生特定影响，并可能影响肿瘤免疫生物标志物的预测价值。