Efficacy and biomarker analysis of neoadjuvant disitamab vedotin combined with immunotherapy in patients with muscle-invasive bladder cancer: A multi-center real-world study.

113 Background: Over half of the patients with muscle-invasive bladder cancer (MIBC) do not benefit from neoadjuvant chemotherapy due to cisplatin intolerance or resistance and have a poor prognosis. Antibody-drug conjugates (ADCs) have shown excellent clinical benefits in advanced MIBC in recent years, but there is a lack of studies using ADCs as neoadjuvant treatment. Methods: Patients with MIBC were eligible for inclusion criteria were included and received neoadjuvant RC48-ADC (disitamab vedotin) combined with toripalimab (n=79) or tislelizumab (n=23). The primary outcome was pathological downstaging, including complete pathological response (CR: pT0N0M0) and partial response (PR: pTa, Tis, and T1N0M0). The secondary outcome was disease free survival (DFS). Logistic regression and biomarker analyses were performed to identify efficacy predictors. Results: 102 patients from four hospitals were enrolled and evaluated for pathological staging. 84 patients (82.4%) had T2N0M0 tumors and 93 patients (91.2%) had pure urothelial carcinoma. 38 patients (37.3%, 95% CI: 27.9% - 47.4%) achieved CR and 77 patients (75.5%, 95% CI: 6.0% - 83.5%) achieved PR. The 1-year DFS rate was 97.4% (95% CI: 92.6% - 100.0%). Subgroup analysis showed that the clinical stage (P=0.001) and histological type (P=0.006) were independent efficacy predictors. However, there was no statistically significant difference between efficacy and HER2 status (P=1.000). Biomarker analysis showed that the enrichment of pathways, such as the extracellular matrix, angiogenesis, and lymphocyte chemotaxis, may be associated with better efficacy. Conclusions: Neoadjuvant RC48-ADC combined with immune checkpoint inhibitors showed promising efficacy in patients with MIBC, irrespective of HER2 expression. This study will expand neoadjuvant treatment strategies for patients who are intolerant to neoadjuvant chemotherapy. [Table: see text]