The efficacy of subsequent therapy after failure of anti-PD-1 antibody in metastatic renal cell carcinoma

Background: The optional regimens of subsequent therapy after failure of anti-programmed cell death protein-1 (PD-1) antibody in metastatic renal cell carcinoma (mRCC) remain to be explored. There are reports of the efficacy of single-agent vascular endothelial growth factor receptor tyrosine kinase inhibitor (VEGFR-TKI) in patients with mRCC after failure of anti-PD-1 antibody therapy. However, it is not clear whether it is beneficial for patients to receive anti-PD-1 antibody as post-progression treatment. It has great significance to explore whether continuous application of anti-PD-1 antibody is beneficial for patients with mRCC whose diseases progressed to the state of pre-anti-PD-1 therapy. The purposes of this study are to explore the efficacy and safety of subsequent treatment on whether to continue using anti-PD-1 antibody therapy for patients who have progressive mRCC after prior treatment with anti-PD-1 antibody. Methods: The clinical data of patients with mRCC from the Department of Immunotherapy in the Affiliated Cancer Hospital of Zhengzhou University and Henan Cancer Hospital from February 1, 2019 to December 31, 2021 were analyzed retrospectively. The primary endpoints were the objective response rate (ORR) and progression-free survival (PFS). The ORR and disease control rate (DCR) were estimated with Fisher's exact test. PFS and overall survival (OS) were assessed using the Kaplan-Meier method and log-rank tests. The associations between potential prognostic variables and PFS were evaluated with univariate and multivariate Cox regression analyses. A P value of less than or equal to 0.05 was deemed as statistically significant. Results: A total of 35 patients were included in this study, during which 19 received VEGFR-TKI monotherapy and 16 received the VEGFR-TKI plus anti-PD-1 antibody therapy. Until the last follow-up on June 30, 2022, 19 patients experienced progressive disease (PD), five were in remission, and 11 kept stable disease (SD). After a median follow-up of 28.7 [95% confidence interval (CI): 17.0-35.6] months, the median PFS (mPFS) was 11.6 months for the VEGFR-TKI group and 9.1 months for the VEGFR-TKI plus anti-PD-1 antibody group [hazard ratio (HR) =0.81, 95% CI: 0.32-1.03, P=0.44]. Median OS (mOS) were 16.9 and 11.2 months respectively (HR =0.99, 95% CI: 0.44-2.27, P=0.90). The ORRs were 26.3% and 0% (P=0.049), and the DCRs were 47.4% and 43.8% (P=0.55) respectively. Treatment-related adverse events (TRAEs) occurred in 14 patients (73.7%) in the VEGFR-TKI group and 14 patients (87.5%) in the VEGFR-TKI plus anti-PD-1 antibody group (P=0.42); grade 3/4 TRAEs occurred in two patients (10.5%) and six patients (37.5%) respectively (P=0.11). Conclusions: VEGFR-TKI monotherapy is an efficacious regimen for patients with mRCC whose diseases progressed on previous anti-PD-1 antibody therapy, and continuous anti-PD-1 therapy after failure of anti-PD-1 antibody could not provide additional clinical benefit but increased the incidence of TRAEs.