Abstract CT529: A Phase 1b Study of CG0070 combined with nivolumab in cisplatin ineligible patients with muscle invasive bladder cancer

Abstract Background: Up to 50% of patients with muscle invasive bladder cancer (MIBC) are unable to receive neoadjuvant chemotherapy, creating an unmet clinical need for alternative systemic treatment. Results from recent neoadjuvant immune checkpoint blockade (ICB) studies signal pCR rates between 31-42%. However, there was a clear dichotomy in response between patients with high vs. low pre-treatment lymphocytic infiltration. In tumors exhibiting immune excluded or immune desert phenotypes, therapeutic strategies to attract CD8+ T cells infiltration prior to ICB may be beneficial. CG0070 is an oncolytic adenovirus designed to preferentially replicate through a transcriptionally regulated promoter that is up-regulated in RB-pathway-defective cells (>70% of MIBC). In addition, CG0070 expresses GM-CSF to attract antigen presenting cells to the tumor microenvironment. We hypothesize that combination therapy using intravesical CG0070 and systemic Nivolumab is 1) safe and 2) can enhance local and systemic treatment response in the neoadjuvant setting against MIBC. Methods: This is a phase Ib trial evaluating 2 doses of nivolumab (4 weeks apart) with 6 weekly intravesical CG0070 followed by cystectomy. Dose-limiting toxicities (DLTs) will be assessed in 6 DLT-evaluable patients in a safety lead-in phase. The combination would be declared tolerable if the incidence of DLTs is <33%, and the study expanded to 30 patients. Key eligibility: cT2-T4aN0-1M0 stage, no autoimmume disease within 2 years, and no concurrent invasive upper tract carcinoma or other active cancer. The primary objective is to evaluate the safety of combination therapy according to CTCAE v5.0. The secondary objective is to assess the changes in the lymphocytic infiltration following combination therapy and to assess the antitumor efficacy of combination therapy. Exploratory endpoints include assessing the predictive value of E2F expression, tumor mutational burden, immune infiltration, and various peripheral blood for treatment response. Study Progress: Study is actively accruing. Clinical trial information: NCT04610671. An update on the study will be provided at the time of presentation. Citation Format: Roger Li, Wade Sexton, Phillipe Spiess, Scott Gilbert, Julio Pow-Sang, Jingsong Zhang, Gustavo Borjas, Paola Grandi, James Burke, Rohit Jain, Jose Conejo-Garcia. A Phase 1b Study of CG0070 combined with nivolumab in cisplatin ineligible patients with muscle invasive bladder cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr CT529.