A comparison of efficacy and prognosis between RC48 combined immunotherapy and gemcitabine-cisplatin combined immunotherapy in bladder-preserving multimodal therapy for muscle-invasive bladder cancer.

objectiveBladder-preserving multimodal therapy has gained increasing recognition for the management of muscle-invasive bladder cancer (MIBC). This study aims to compare the efficacy and safety of disitamab vedotin combined with anti-PD-1 agents (RC48 + PD-1) versus gemcitabine plus cisplatin chemotherapy combined with anti-PD-1 agents (GC + PD-1) among MIBC patients receiving bladder-preserving multimodal therapy.

methodsThis was a single-center real-world retrospective cohort study. Patients diagnosed with MIBC who received bladder-preserving multimodal therapy at our hospital between January 2021 and September 2024 were enrolled. Participants were stratified into two groups according to their systemic treatment regimens: RC48 + PD-1 group and GC + PD-1 group. Propensity score matching (PSM) was performed to adjust baseline clinical characteristics and mitigate potential selection bias. Primary comparative endpoints between the two cohorts included objective response rate (ORR), disease control rate (DCR), progression-free survival (PFS), overall survival (OS), and treatment-related adverse events (TRAEs).

resultsA total of 143 patients with MIBC were initially enrolled, including 68 patients receiving RC48 + PD-1 inhibitor and 75 patients treated with GC + PD-1 inhibitor. After 1:1 PSM to balance baseline characteristics, a matched cohort consisting of 104 patients (52 patients per group) was generated for final analyses. Analysis of the matched cohort revealed that the ORR was significantly higher in the RC48 + PD-1 group than in the GC + PD-1 group (p = 0.013), whereas no statistically significant intergroup difference was observed in DCR. The median follow-up duration was 20 months (range, 8-56 months). Disease progression occurred in 43 patients (41.3%) across the entire matched cohort, with a median time to progression of 14 months (range, 2-45 months); 30 progression events were recorded in the GC + PD-1 group and 13 in the RC48 + PD-1 group. Multivariable Cox proportional hazards regression analysis revealed three independent predictors of PFS:receipt of repeated TURBT, and RC48 + PD-1 treatment were independent favorable prognostic factors, whereas HER2-positivity independently increased the risk of disease progression. Kaplan-Meier survival analysis demonstrated significantly superior PFS in patients receiving RC48 + PD-1 compared with those treated with GC + PD-1 (p < 0.05), while OS was comparable between the two arms (p = 0.42). Subgroup analysis, excluding HER2-negative patients, yielded consistent survival patterns with those observed in the overall matched cohort. In terms of safety, neither severe hypersensitivity reactions nor treatment-related deaths were documented in either group. The incidence of grade 3-4 TRAEs was 7.7% in the RC48 + PD-1 group versus 19.2% in the GC + PD-1 group, without a statistically significant between-group difference (p = 0.149).

conclusionsWhether HER2-negative patients were excluded or retained in the analysis, treatment with RC48 combined with immunotherapy yielded superior ORR and prolonged PFS, with no statistically significant intergroup difference in OS. This regimen demonstrates favorable antitumor efficacy and tolerability and may serve as an alternative clinical strategy for bladder-preserving multimodal therapy in patients with MIBC.