Association between prior nephrectomy and efficacy of immune checkpoint inhibitor therapy in metastatic renal cell carcinoma - A systematic review and meta-analysis

Background Immune checkpoint-inhibitor (ICI)-based therapy is the standard of care for first-line treatment of metastatic renal cell carcinoma (mRCC). It is unclear whether prior removal of the primary tumor influences the efficacy of these treatments. We performed a systematic review and meta-analysis of studies of first-line ICI in mRCC to determine whether the efficacy of ICI-therapy, compared to sunitinib, is altered based on receipt of prior nephrectomy. Methods We systematically reviewed studies indexed in MEDLINE (PubMed), Embase, and Scopus and conference abstracts from relevant medical societies as of August 2020 to identify randomized clinical trials assessing first-line immunotherapy-based regimes in mRCC. Studies were included if overall survival (OS) and progression-free survival (PFS) outcomes were reported with data stratified by nephrectomy status. We pooled hazard ratios (HRs) stratified by nephrectomy status and performed random effects meta-analysis to assess the null hypothesis of no difference in the survival advantage of immunotherapy-based regimes based on nephrectomy status, while accounting for study level correlations. Results Among 6 randomized clinical trials involving 5,121 patients, 3,968 (77%) had undergone prior nephrectomy. We found an overall survival benefit for immunotherapy-based regimes, compared to sunitinib, among both patients who had undergone nephrectomy (HR 0.75, 95% CI 0.63 –0.88) and those who had not (HR 0.74, 95% CI 0.59 –0.92), without evidence of difference based on nephrectomy history (P = 0.70; I2 = 36%). Results assessing PFS were similar (P = 0.45, I2 = 0%). Conclusions These clinical data suggest that prior nephrectomy does not affect the efficacy of ICI-based regimens in mRCC relative to sunitinib.