3188 - Mid-Term Analysis of the Combination Therapy of Axitinib, Toripalimab, and Stereotactic Ablative Body Radiotherapy (SABR) in the Treatment of Recurrent Metastatic Renal Cell Carcinoma

K. Hu, M. W. Ma, X. S. Gao, J. Y. Chen, X. Y. Li, S. B. Qin, and X. Ren; Department of Radiation Oncology, Peking University First Hospital, Beijing, China

Purpose/Objective(s): This study aims to explore the safety and efficacy of the combination therapy of Axitinib, Toripalimab, and Stereotactic Ablative Body Radiotherapy (SABR) in the treatment of recurrent metastatic renal cell carcinoma. Materials/

Methods: This study is a single-center prospective study, where all patients received Axitinib, Toripalimab, and comprehensive SABR treatment covering multiple lesions as much as possible. The primary endpoint was progression-free survival (PFS), and secondary endpoints included overall survival (OS), objective response rate (ORR), and disease control rate (DCR). Adverse events were assessed according to the Common Terminology Criteria for Adverse Events version 5.0 (CTCAE 5.0).
Results: A total of 19 patients were included, among whom 63.2% were clear cell carcinoma, and 73.7% had oligometastases. The median follow-up time was 12.5 months. The overall ORR was 73.7%, and DCR was 94.7%. DCR for radiation lesions was 100%. The median PFS was 20.0 months. Until October 1, 2023, 16 out of 19 patients were still alive. The 1-year and 2-year OS rates and PFS rates were 100% and 73.7%, 94.7%, and 63.2%, respectively. The median time to switch to the next-line treatment due to disease progression was 30.6 months. Regarding efficacy, both of PFS and ORR are higher than the data from studies on Axitinib combined with immunotherapy alone. In a study of 19 patients, 8 patients (33.9%) experienced Grade 1-2 adverse reactions, while 11 patients (47.4%) experienced Grade 3-4 adverse reactions. Adverse reactions with an incidence rate of >10% included fatigue (57.9%), hypertension (52.6%), infections (10.5%), edema (10.5%), pain (36.8%), rash or hand-foot syndrome (53.6%), proteinuria (31.6%), myocarditis (15.8%), nausea and vomiting (31.6%), decreased appetite (31.6%), esophageal or pharyngeal pain, hoarseness (26.3%), diarrhea, gastrointestinal bleeding (73.7%), pneumonia (26.3%), liver function abnormalities (57.9%), renal function abnormalities (42.1%), thyroid function abnormalities (42.1%), musculoskeletal pain, myositis (15.8%), anemia (36.8%), leukopenia or neutropenia (26.3%), and thrombocytopenia (21.1%). Adverse reactions in patients improved after symptomatic treatment, dose reduction, or discontinuation of the medication.The combination of Axitinib and Teriparatide monoclonal antibody with SABR radiotherapy has good safety, with the incidence of =Grade 3 adverse reactions being lower than domestic and international data. However, due to the small sample size, there may be selection bias.
Conclusion: Mid-term analysis results show that the combination therapy of Axitinib, Toripalimab, and Stereotactic Ablative Radiotherapy has achieved satisfactory survival outcomes in patients with recurrent/metastatic renal cancer, with manageable adverse reactions. Long-term follow-up data are still needed for validation.