A Single-arm, Phase II Clinical Trial to Treat Muscle-invasive Bladder Cancer With Neoadjuvant Chemotherapy Plus Anti-PD-1 Therapy Followed by Radiotherapy Plus Concurrent Anti-PD-1 Therapy

Bladder cancer is the second most common malignancies over the world. At initial diagnosis, the cases with muscle-invasive bladder cancer (MIBC) accounts nearly 20% of all bladder cancer patients. And 40% of non-muscle-invasive bladder cancer could develop to MIBC. Currently, radical cystectomy (RC) is the golden standard to manage MIBC. Yet, it brings severe surgical injuries and post-surgical complications which impair life quality of the patients. Recently, bladder-preserving treatment based gradually becomes the second choice for MIBC. It consists of maximal transurethral resection of bladder tumor (TURBT) and chemoradiation. A series of clinical trials and meta-analyses supported that the bladder-preserving treatment has a similar therapeutic effect compared with RC. But it is noteworthy that this treatment mode does not really avoid surgery. TURBT could also cause complications, such as haemorrhage, infection, perforation, and even tumor dissemination. Moreover, the incidence of serious toxicities brought by concurrent chemoradiation is as high as 36%. In actual clinical work, it is hard for more than half patients to complete chemoradiation of standard intensity. Additionally, many patients are unsuitable for bladder preservation, including those with T stage > T2, diameter > 5 cm, hydronephrosis and positive lymph nodes. Hence, it calls for improvement of current bladder preservation mode, to make more MIBC patients receive radical treatment which brings better therapeutic experience and life quality.

Many lab studies indicated that formation and progression of bladder cancer is a process of mutation accumulation. It provides biological fundamentals for immune checkpoint inhibitors, such as anti-programmed cell death protein 1 (anti-PD-1) antibodies. Based on available clinical studies, anti-PD-1 antibodies exhibits ideal therapeutic effects in bladder cancer of different stages and has an incidence of toxicities as low as 13%. Its toxicities mainly include arthralgia and hyponatremia, which are well tolerated. Currently, there are more than 10 clinical trials trying anti-PD-1 antibodies for bladder preservation. However, the treatment modes in most of them still contain TURBT. This phase 2 trial intended to evaluate the therapeutic and adverse effects of a non-surgical bladder-preserving treatment mode consisting of anti-PD-1 antibodies and chemoradiation, in a small patient cohort with MIBC. The results might provide an effective, non-invasive and low-toxic choice which improves patient experience and realizes bladder preservation.