Abstract
INTRODUCTION: There is a significant gap in the literature concerning the effective management of second-line therapy for patients with metastatic renal cell carcinoma (RCC) who have received immune checkpoint inhibitors (ICIs). Most of the published articles were small multicenter series or phase 2 studies. To our knowledge, a systematic review that comprehensively outlines the range of treatment options available for patients with metastatic RCC who do not respond to first-line ICIs has not yet been conducted. Our aim was to synthesize evidence on second-line therapies for patients with metastatic RCC after initial treatment with ICIs and to offer recommendations on the best treatment regimens based on the current literature. MATERIAL AND METHODS: We conducted a search in PubMed, Embase, and the Cochrane Library on 29 February 2024, following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. We selected articles that met the predetermined inclusion criteria (written in English, retrospective observational studies, prospective series, and randomized trials reporting second-line therapy for metastatic RCC after failure of ICI-based therapy). Relevant articles were identified in the reference lists. The main endpoint was the overall response rate (ORR), with the median progression-free survival (PFS) and overall survival (OS) as secondary endpoints. RESULTS: We included 27 studies reporting the outcomes of 1970 patients. Salvage therapies were classified as targeted therapy (VEGFR TKIs) in 18 studies and ICIs in 8 studies. In studies where TKIs were the second line of choice, the pooled ORR was 34% (95% CI: 30.2-38%). In studies where ICIs, alone or in combination with TKIs, were used as second-line therapies, the ORR was 25.7% (95% CI: 15.7-39.2%). In studies where TKIs and ICIs were the second-line choices, the pooled median PFS values were 11.4 months (95% CI: 9.5-13.6 months) and 9.8 months (95% CI: 7.5-12.7 months), respectively. CONCLUSIONS: This systematic review shows that VEGFR TKIs and ICIs are effective second-line therapies following an initial treatment with anti-PD(L)1 alone or in combination. The treatment choice should be personalized, taking into account the patient's response to first-line ICIs, the site of the disease, the type of first-line combination (with or without VEGFR TKIs), and the patient's overall condition.