Efficacy and safety of a novel treatment scheme of RC48-ADC plus PD-1 inhibitors in metastatic urothelial carcinoma: a multicenter real-world study.

Background: Metastatic urothelial carcinoma (mUC) remains a challenging malignancy with limited treatment options. The combination of RC48 (Disitamab Vedotin) plus programmed cell death protein 1 (PD-1) inhibitor represents a promising therapeutic strategy. Objectives: To evaluate the efficacy and safety of RC48 plus PD-1 inhibitors as first-line therapy for mUC in real-world practice. Design: A multicenter, retrospective cohort study. Methods: We retrospectively collected data from mUC patients who received RC48 plus PD-1 inhibitors as first-line therapy between July 2021 and February 2024 from three medical centers. Overall survival (OS), progression-free survival (PFS), objective response rate (ORR), and disease control rate (DCR) were calculated to evaluate the clinical efficacy. Treatment-related adverse events (TRAEs) were analyzed to assess the safety profiles. Results: A total of 63 patients with mUC were included, with a mean age of 67 years, and 71.4% were male. The most frequent metastatic sites were lymph nodes (77.8%), followed by the lung (31.7%), bone (23.8%), liver (19.0%), and others. The treatment response rates were as follows: 12 patients (19.0%) achieved a complete response, 33 patients (52.4%) had a partial response, and 10 patients (15.9%) experienced stable disease. The ORR was 71.4%, and the DCR was 87.3%. The median PFS was 10.5 months (95% confidence interval: 8.8-14.6 months), and the median OS was not reached. The most common TRAEs included fatigue (36.5%), anemia (34.9%), pruritus (33.3%), peripheral sensory neuropathy (28.6%), and nausea (28.6%). Grade III TRAEs occurred in seven patients (11.1%), and no Grade IV or V TRAEs were observed. Conclusion: The combination of RC48 and PD-1 inhibitors administered in 3-week cycles demonstrates efficacy and manageable safety as first-line therapy for mUC patients in a real-world setting.