Therapeutic sequencing in the era of first-line immune checkpoint inhibitor combinations, a novel challenge in patients with metastatic clear-cell renal cell carcinoma

Immune checkpoint inhibitor combinations have reshaped the treatment landscape of metastatic clear-cell renal cell carcinoma. As four regimens are now approved in the first-line setting, including nivolumab plus ipilimumab in intermediate and poor-risk patients, and pembrolizumab plus lenvatinib, nivolumab plus cabozantinib and pembrolizumab plus axitinib in all-comers, the choice of subsequent therapies is becoming a novel challenge for physicians. Such choices now rely on several compounds used as monotherapy which have demonstrated sustained activity after previous immune checkpoint or tyrosine kinase inhibitors. Future strategies may lie in novel targets, including hypoxia-inducible factor inhibitors, as well as further exploration of combinations in more advanced settings. Here we review the current evidence regarding treatment activity after immune checkpoint inhibitor combinations, the underlying biological and clinical challenges that may impact patient selection and the optimal sequencing strategies for clinical practice.