Safety and Efficacy of Second-Line TKI Plus Anti-PD1 in Metastatic Non-Clear Cell Renal Cell Carcinoma: A Real-World Study

This study assessed second-line therapy options for metastatic non-clear cell renal cell carcinoma (nccRCC) patients following first-line tyrosine kinase inhibitor (TKI) treatment. Among 65 patients, combination therapy (TKI plus anti-PD1) showed improved response rates (ORR 50.0%, DCR 70.5%) compared to TKI monotherapy (ORR 14.3%, DCR 28.6%). Median progression-free survival (PFS) for combination therapy was 9.2 months vs. 5.4 months for TKI monotherapy, with similar adverse event rates. Anti-PD-1 plus TKI therapy appears effective and safe for nccRCC patients who progressed after initial TKI treatment. Objectives: Guidelines recommend clinical trials or tyrosine kinase inhibitor (TKI) as the first-line option for systemic therapy for non-clear cell renal cell carcinoma (nccRCC) with limited efficacy. However, the preferred subsequent options remain unclear when patients progress after first-line treatment. This study aimed to evaluate the efficacy and safety of anti-PD-1 plus TKI therapy as the second-line regimen in nccRCC. Patients and Methods: We conducted a retrospective analysis of patients with metastatic nccRCC who failed first-line TKI therapy between October 2011 and September 2020. The baseline characteristics of the patients and adverse events (AEs) were collected. Efficacy measures included objective response rate (ORR), disease control rate (DCR), progression-free survival (PFS) and overall survival (OS). Results: The current study enrolled 65 patients, with a median age of 48 (interquartile 37-60) years. Among all patients, 21 received TKI monotherapy while 44 patients received combination therapy (TKI plus anti-PD1). The ORR and DCR for the whole cohort were 38.5% and 56.9%, respectively. ORR (50.0% vs. 14.3%, P = .006) and DCR (70.5% vs. 28.6%, P = .001) were improved in the combination group compared with the TKI group. The overall second-line PFS was 7.7 (95% CI: 6.1-9.3) months and OS was 25.2 (19.5-30.8) months. Patients receiving combination therapy had a longer PFS compared with those receiving TKI monotherapy [median PFS (95% CI): 9.2 (5.9-12.4) vs. 5.4 (2.6-8.2) m, Log-rank P = .002]. The incidence of treatment-related AEs of grade 3 or higher was comparable between the 2 groups (56.8% vs. 52.4%). Conclusion: Anti-PD-1 plus TKI therapy appeared effective and safe in the treatment of patients with metastatic nccRCC who progressed after first-line TKIs.