Neoadjuvant therapy with camrelizumab plus gemcitabine and cisplatin for patients with muscle-invasive bladder cancer: A multi-center, single-arm, phase 2 study

Background: Neoadjuvant chemotherapy followed by radical cystectomy (RC) is the standard of care for patients with muscle--invasive bladder cancer (MIBC). However, treatment outcomes are suboptimal. Camrelizumab, a PD--1 blockade, has shown benefits in several tumors. This study aimed to investigate the efficacy and safety of neoadjuvant camrelizumab in combination with gemcitabine plus cisplatin (GC) followed by RC for MIBC patients. Methods: This was a multi-center, single--arm study that enrolled MIBC patients with a clinical stage of T2-4aN0-1M0, and scheduled for RC. Patients received three 21-day cycles of camrelizumab 200 mg on day 1, gemcitabine 1000 mg/m(2) on day 1 and 8, and cisplatin 70 mg/m(2) on day 2, followed by RC. The primary endpoint was pathologic complete response (pCR, pT0N0). Results: From May 2020 to July 2021, 43 patients were enrolled and received study medications at nine centers in China. Three of them were deemed ineligible and excluded from efficacy analysis but included in safety analysis. In total 10 patients were unevaluable as they declined RC (two due to adverse events [AEs] and eight due to patient's willingness). Among 30 evaluable patients, 13 patients (43.3%) achieved pCR, and 16 patients (53.3%) achieved pathologic downstaging. No AEs leading to death were observed. The most common AEs were anemia (69.8%), decreased white blood cell count (65.1%), and nausea (65.1%). Immune-related AEs were all grade 1 or 2. Pathologic response was not correlated with PD-L1 expression status or tumor mutation burden. Individual genes as a biomarker for pathologic response were not identified. Conclusions: Neoadjuvant treatment with camrelizumab and GC regimen demonstrated preliminary anti--tumor activity for MIBC patients with manageable