Abstract CT086: Phase I study of intravesical Fc-optimized anti-CD40 agonist antibody 2141-V11 for non-muscle invasive bladder cancer (NMIBC) unresponsive to Bacillus Calmette-Guerin (BCG) therapy

Abstract Introduction: The CD40-CD40L pathway is crucial for activating antigen-presenting cells and initiating tumor-specific T cell responses across various malignancies. However, prior agonistic anti-CD40 antibodies have encountered limited clinical success and significant toxicity. Our previous studies demonstrate that interactions between the antibody Fc domain and the inhibitory Fc-gamma receptor FcγRIIB are critical for efficient CD40 multimerization and enhanced antitumor activity. To optimize this interaction, we developed 2141-V11, a novel anti-CD40 antibody Fc-engineered to increase binding affinity for FcγRIIB, resulting in effective antitumor activity in both in vivo and in a recent first-in-human phase I trial (NCT04059588). Non-muscle invasive bladder cancer (NMIBC) is the most common presentation of bladder cancer, with a high risk of recurrence and progression despite optimal surgical interventions and standard therapies. Bacillus Calmette-Guerin (BCG) intravesical treatment has been the standard of care for NMIBC over the last five decades. However, 75% of patients ultimately become unresponsive to this therapy, leaving limited curative options aside from complete radical cystectomy. Using several preclinical bladder cancer models, including BCG-unresponsive disease, we found that intravesical administration of 2141-V11 induces durable anti-tumor immunity without systemic toxicity. Based on these findings, we initiated a Phase I study of intravesical 2141-V11 for the treatment of BCG-unresponsive NMIBC. Methods: This is an investigator-initiated Phase I, open-label, dose-escalation study to evaluate the safety and tolerability of intravesical 2141-V11 in patients with BCG-unresponsive NMIBC (N=25) who are ineligible for or decline radical cystectomy (NCT05126472). Following complete transurethral resection, intravesical 2141-V11 is administered once weekly for three doses, with re-treatment eligibility at week 13 and 25, based on disease status determined by on-treatment biopsies. The study follows an MCRM dose escalation design with five dose levels (0. 7, 2. 0, 7. 0, 21. 0 and 70. 0 mg). Primary endpoints include safety and dose tolerability to determine maximal tolerated dose (MTD) and/or recommended phase 2 dose (RP2D). Secondary endpoints involve pharmacokinetic profiling and preliminary evaluation of clinical activity. Exploratory objectives include investigation of biological markers of drug activity in pre- and post-treatment tissue biopsies and urine biospecimens. As of the data cutoff on 12/20/23, 80% of the planned patients (n=20) have been enrolled, with no dose-limiting toxicities observed. Accrual completion is expected by the first quarter of 2024, with ongoing analysis of urine immune profiling, cytokine analysis, as well as single-cell spatial phenotyping in pre- and post-treatment samples. Citation Format: Juan C. Osorio, Muneeb Alam, Jeffrey Wong, David Knorr, Lucas Blanchard, Juan C. Angulo-Lozano, Karissa Whiting, Venkatraman E. Seshan, Timothy F. Donahue, Eugene K. Cha, Alvin C. Goh, Robert Smith, Guido Dalbagni, Christian Hernandez, Melissa McCarter, Eugene J. Pietzak, Jonathan E. Rosenberg, Jeffrey V. Ravetch, Bernard H. Bochner. Phase I study of intravesical Fc-optimized anti-CD40 agonist antibody 2141-V11 for non-muscle invasive bladder cancer (NMIBC) unresponsive to Bacillus Calmette-Guerin (BCG) therapy abstract. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts) ; 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84 (7Suppl): Abstract nr CT086.