Efficacy and safety of camrelizumab plus apatinib in advanced urachal cancer (RUN-SC-0102): a single-arm, multicentre, phase 2 trial in China.

Background: Urachal carcinoma (UrC) constitutes a rare and biologically distinct adenocarcinoma for which no standardised therapeutic regimen currently exists. We aimed to evaluate the efficacy and safety of combined therapy with camrelizumab, a humanised monoclonal anti programmed death-1 (PD-1) antibody, plus apatinib, a vascular endothelial growth factor receptor (VEGFR) inhibitor, in patients with advanced UrC. Methods: RUN-SC-0102 is an open-label, single-arm, phase 2, multicohort trial that followed a Simon's two-stage MiniMax design and enrolled participants with rare cancer types. Here, we report the urachal cancer cohort, which enrolled patients across two centres in China (Shanghai, Beijing) with histologically confirmed UrC who were refractory to at least one line of systemic chemotherapy. Patients with prior exposure to PD-1/PD-L1 or VEGF-targeted agents were ineligible for enrolment. Participants received camrelizumab (200 mg; intravenous) once every 3 weeks and apatinib (250 mg; oral). The primary endpoint was the objective response rate (ORR). Secondary endpoints were progression-free survival (PFS), overall survival (OS), duration of response (DoR), disease control rate (DCR), clinical benefit rate (CBR), and safety. Efficacy analysis was performed in the intention-to-treat (ITT) population. Safety analyses were performed on all patients who received at least one dose of study treatment. This trial was registered with the Chinese Clinical Trial Registry, ChiCTR2400086153. Findings: Between June 1, 2024, and Jan 31, 2025, 20 patients with UrC were enrolled. As of data cutoff (Sept 30, 2025), the ORR was 40% (95% CI 19.8-63.1) and the CBR was 50% (95% CI 27.2-72.8). Median DoR was 7.5 months (95% CI 7.0-not reached) and median PFS was 5.5 months, (95% CI 3-not reached). The DCR was 95% (95% CI 79.2-99.2), comprising 8 partial responses (PR) and 11 stable diseases (SD) as best overall response. Median OS was not reached, with a median follow-up duration of 13.6 months (9.9-not reached). Nine patients (45%) experienced grade 3 and 4 adverse events. No grade 5 toxicities were observed. Interpretation: As the first reported trial of its kind in advanced urachal carcinoma, this study demonstrates that combined PD-1 and VEGFR inhibitor therapy is well tolerated and clinically active, warranting further investigation in biomarker-enriched, adequately powered trials. Funding: None.