A pilot prospective study of tislelizumab and axitinib combined with stereotactic body radiation therapy for oligometastatic renal cell carcinoma

Abstract

<title>Abstract</title> Background The aim of this study is to investigate the efficacy and safety of tislelizumab and axitinib combined with SBRT in the treatment of omRCC. Methods Eligible pts had oligometastases (≤ 5 leisions) and ≤ 1 prior systemic therapy. All patients received SBRT to metastatic lesions using the CyberKnife platform (Accuray Inc., Sunnyvale, CA, USA). Concomitant tislelizumab was given 200mg every 3 weeks and axitinib 5mg twice a day. Primary endpoint was objective response rate (ORR) according to RECIST v1.1. Secondary endpoints included progression free survival (PFS) and overall survival (OS) estimated using Kaplan Meier method. Treatment-related adverse events (TRAEs) were evaluated based on CTCAE 5.0. Trial registration: Chinese Clinical Trial Registry, ChiCTR2200067043. Registered 26 December 2022. Results From March 2022 and October, 2024, among 21 pts with oligometastatic ccRCC (median follow-up 16.4 mo), ORR was 66.7% and DCR 95.2%. Differential responses to SBRT were observed based on metastatic site. Irradiated bone lesions achieved a higher ORR than non-irradiated lesions (53.3% vs. 28.6%), whereas irradiated and non-irradiated lung lesions showed comparable ORRs (40.0% vs. 50.0%). Overall, irradiated lesions achieved a higher disease control rate (95.2% vs 85.7%) than non-irradiated lesions. CR occurred only in irradiated lesions. Median PFS was 387 d, median OS 740 d. 1-yr OS and PFS rates were 100% and 57.9%, respectively. TRAEs occurred in 90.5% of pts, mostly G1–2; only 3 G3–4 events were observed. No treatment-related deaths and no new safety signals were reported Conclusions The preliminary results of tislelizumab plus axitinib combined with SBRT demonstrates promising efficacy and safety in the treatment of omRCC. Importantly, SBRT provided enhanced local control for oligoprogressive sites (notably in bone), which may delay the need for switching therapy. The results support this multimodal approach as a feasible and complementary strategy for improving outcomes in this patient population.