3281 - Combination of Axitinib, Toripalimab, and Radical-Dose Radiotherapy for Recurrent or Metastatic Renal Cell Carcinoma: A Single-Center Prospective Study

12:45pm - 02:00pm PT

Hall F

Screen: 6

POSTER

Presenter(s)

Mingwei Ma, MD - Peking University First Hospital, Beijing, Beijing

M. Ma¹, K. Hu¹, H. Li¹, W. Yu², and X. Gao¹; ¹Department of Radiation Oncology, Peking University First Hospital, Beijing, China, ²Department of Urology, Peking Universtiy First Hospital, Beijing, China

Purpose/Objective(s): This study investigates the safety and efficacy of combining Axitinib, Toripalimab, and radical-dose radiotherapy in the treatment of recurrent metastatic renal cell carcinoma (RCC).

Materials/Methods: This single-center, prospective study enrolled patients with recurrent or metastatic renal cell carcinoma, including those who may have previously received targeted therapy. All patients were treated with a regimen consisting of Axitinib and Toripalimab in combination with Stereotactic Ablative Body Radiotherapy (SABR). Axitinib (5 mg orally twice daily) and Toripalimab (240 mg intravenously every 3 weeks) were administered as systemic therapy. Radiotherapy was tailored based on lesion location and proximity to organs at risk. For lesions distant from organs at risk, SABR was delivered at doses of 8-10 Gy/f × 5 fractions, while for lesions near organs at risk, partial-SABR (P-SABR) was applied with peripheral doses of =2-2.5 Gy/f × 20-25 fractions, and central tumor doses ranged from 8-12 Gy/f × 3 fractions. When disease progression occurred following initial radiotherapy, additional radiotherapy could be administered to progressing lesions.

The primary endpoint was Progression-Free Survival 1 (PFS1), defined as the time from treatment initiation to disease progression or death. The secondary endpoints included PFS2, Objective Response Rate (ORR), Disease Control Rate (DCR), Local Relapse-Free Survival (LRFS), and Overall Survival (OS). PFS2 is defined as the time to the need for a second-line treatment due to disease progression. Adverse events were assessed according to the CTCAE version 5.0.

Results: A total of 30 patients were enrolled, with a median follow-up of 23.1 months. Among the patients, 21 (70%) had clear cell carcinoma. The overall ORR was 60%, and the DCR was 80%, with irradiated lesions showing a DCR of 96.7%. The 1, 2, and 3-year LRFS rates were 100%, 95.5%, and 95.0%, respectively. The 1, 2, and 3-year PFS1 rates were 70.6%, 47.0%, and 34.3%, respectively, with a median PFS1 of 21.0 months (95% CI: 7.0-35.0 months). The 1, 2, and 3-year PFS2 rates were 74.1%, 69.1%, and 59.2%, respectively, with the median PFS2 not yet reached. The 1, 2, and 3-year OS rates were 96.3%, 91.2%, and 76.6%, respectively, with a median OS of 44.8 months (95% CI: 20.0-69.6 months).

Subgroup analysis revealed that radiotherapy administered before targeted therapy failure significantly prolonged PFS1 (28.6 months vs. 6.9 months, p=0.007) and PFS2 (not reached vs. 6.9 months, p=0.003).

Grade = 3 adverse events mainly included diarrhea, fatigue, hypertension, and liver dysfunction, with an incidence rate of 50%.

Conclusion: The combination of Axitinib, Toripalimab, and radical-dose radiotherapy is effective in treating recurrent or metastatic renal cell carcinoma and can delay the need for subsequent line treatments. Early intervention with radiotherapy significantly improves PFS, while the treatment regimen demonstrates a favorable safety profile.