Patients with sarcomatoid renal cell carcinoma – re-defining the first-line of treatment: A meta-analysis of randomised clinical trials with immune checkpoint inhibitors

Background: Sarcomatoid renal cell carcinoma (sRCC) represents a rare form of renal cell carcinoma marked by an aggressive biology, poor prognosis and little benefit from anti-angiogenic targeted therapy. More promising results come from the recent therapeutic strategy based on immune checkpoint inhibitor (ICI) combinations. Materials and methods: For this meta-analysis, we searched MEDLINE/PubMed, the Cochrane Library and American Society of Medical Oncology (ASCO) Meeting abstracts for phase II or III randomised clinical trials. Data extraction was conducted according to the Preferred Reporting Items for Systematic Review and Meta-Analysis statement. The hazard ratios (HRs) for progression-free survival (PFS) and overall survival (OS) with the relative 95% confidence intervals were extracted from studies. Summary HRs were calculated using random- or fixed-effects models, depending on the heterogeneity of the included studies. Results: Four studies were selected for final analysis, including 467 patients (226 treated in with ICI combinations and 241 received sunitinib in the control arms). ICI-based combinations were associated with an improved PFS and OS compared with sunitinib, with a reduction of more than 40% of progression (HR = 0.56; p < 0.0001) and mortality (HR = 0.56; p = 0.001) risk. Moreover, ICI-based combinations are associated with a objective response rate (ORR) of more than 50% (versus 20% with sunitinib), corresponding to a doubled risk of achieving an ORR compared with controls (relative risk [RR] = 2.15; p < 0.00001). Finally, immunotherapy significantly increased the possibility to obtain complete responses (RR = 8.15, p = 0.0002) with an incidence of 11%. Conclusion: Our data support the efficacy of ICI-based combinations for sRCC therapy, redefining the first-line treatment.