[Efficacy and safety evaluation of immunotherapy combined with targeted therapy as second-line treatment in patients with metastatic non-clear cell renal cell carcinoma].

Objective: This study aimed to evaluate the efficacy and safety of programmed death-1 (PD-1) inhibitor combined tyrosine kinase inhibitor (TKI) therapy versus TKI monotherapy as the second-line regimen for patients with metastatic non-clear cell renal carcinoma (nccRCC) who failed first-line TKI therapy. Methods: The clinicopathological data of 67 patients with metastatic nccRCC who failed first-line TKI therapy between October 2011 and September 2020 were retrospectively analyzed, including 22 patients who received TKI monotherapy and 45 patients who received TKI plus PD-1 inhibitor as the second-line therapy. The efficacy was assessed according to Response Evaluation Criteria in Solid Tumors version 1.0/1.1 (RECIST 1.0/1.1), the Kaplan-Meier method was used to plot the survival curves, and the Log rank test was used to analyze the differences in the survival between the two groups. Treatment-related adverse events (AEs) after treatment were observed in both groups. Results: The overall objective response rate (ORR) and disease control rate (DCR) were 37.3% (25/67) and 56.7% (38/67), respectively. The overall second-line progression-free survival (PFS) was 7.7 months and Overall Survival (OS) was 25.2 months. The ORR and DCR of patients in the combination therapy group were 48.9% (22/45) and 71.1% (32/45), respectively, which were significantly improved compared with the TKI monotherapy group [13.6% (3/22) and 27.3% (6/22), respectively] (P=0.007 and P=0.001, respectively). The median PFS of 9.2 months for second-line treatment was longer in patients in the combination therapy group than in the TKI monotherapy group (5.2 months, P=0.001), but the median OS was not statistically different between the two groups (28.2 months vs 20.8 months, P=0.068). Common treatment-related AEs included hypertension, diarrhea, fatigue, stomatitis, hand-foot syndrome, and hypothyroidism. The incidence of hypothyroidism was higher in the combination therapy group [40.0% (18/45)] than in the TKI monotherapy group [22.7% (5/22), P=0.044]; the incidence of other treatment-related AEs between the two groups were not statistically significant (all P>0.05). Conclusion: Immune-targeted combination therapy was more effective than TKI monotherapy alone and was well tolerated in the treatment of metastatic nccRCC patients who failed first-line TKIs.