Taris Biomedical has announced the dosing of the first patient in a study of its TAR-200 system plus a programmed immune checkpoint inhibitor for the treatment of muscle-invasive bladder cancer (MIBC).

The TAR-200 system continuously delivers the chemotherapy drug gemcitabine in the bladder for multiple weeks. The combination with Bristol-Myers Squibb’s Opdivo (nivolumab) will be assessed for safety, tolerability and preliminary efficacy.

The open-label, multi-center, single group assignment Phase 1b clinical study will enroll up to 25 patients with MIBC who are scheduled for radical cystectomy (surgical removal of the bladder). TAR-200 and Opdivo will each be administered on day one of four consecutive 21-day dosing cycles, for a total dosing period of 84 days prior to radical cystectomy.

The preferred standard of care for MIBC is radical cystectomy with a neoadjuvant course of platinum-based chemotherapy. Although this neoadjuvant therapy has been shown to boost survival versus cystectomy alone, it is used in less than 15% of patients scheduled for cystectomy, due primarily to concerns around patient frailty and potential delays to surgery, according to a 2018 study published in the European Journal of Urology Oncology.

Officials at Taris believe that a neoadjuvant regimen such as the combination of TAR-200 plus Opdivo, which has the potential to be used in the large majority of patients not receiving platinum-based therapy, would address a substantial unmet need.

“This clinical trial will be the first to evaluate the combination of the locally-administered TAR-200 system with a systemic PD-1 checkpoint inhibitor, approved for previously treated adults with advanced bladder cancer,” said Taris chief medical officer Dr. Christopher J. Cutie in a news release. “We are eager to evaluate the potential antitumor and immunologic synergy of this product combination administered prior to surgery.”

Bristol-Myers Squibb (NYSE:BMY) is also an equity investor in Lexington, Mass.-based Taris.

Taris continues to study TAR-200 separately as a single agent for the treatment of MIBC patients not receiving surgery