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Abstract Background: Bacillus Calmette-Guérin (BCG) remains the most efficacious and widely studied intravesical therapy for NMIBC, but less than 50% of BCG-exposed patients will respond to a second course of BCG. One mechanism of resistance to BCG is an immunosuppressive tumor microenvironment with myeloid-derived suppressor cells (MDSCs), tumor associated macrophages (TAMs), and Tregs that abrogate the anti-tumor immune response. IL-6 is associated with MDSCs and BCG resistance. Gemcitabine (Gem), however, has been shown to selectively inhibit MDSCs, TAMs, and Tregs. This observation served as the biologic rationale for our recently completed Phase I trial of combination chemoimmunotherapy with intravesical Gem and BCG for BCG-exposed high-grade (HG) NMIBC (NCT04179162) that demonstrated excellent tolerability and preliminary efficacy (96% complete response at 6-month follow-up). We sought to evaluate immune modulation with the addition of Gem to BCG as determined by changes in urinary cytokine/chemokine levels. Methods: Patients with BCG-exposed papillary HG NMIBC (Ta/T1) +/- carcinoma in situ recurring within 24 months of BCG therapy were treated with intravesical Gem twice weekly (weeks 1, 4, 7, 10; 8 total doses) and intravesical TICE BCG weekly (weeks 2, 3, 5, 6, 8, 9; 6 total doses) followed by SWOG maintenance BCG for responders. Urine specimens were collected prior to treatment and on weeks 4, 8, 12, 24, and 52 weeks after on-trial treatment initiation. Urinary cytokines present in the supernatant were evaluated using a 96-plex immuno-oncology proximity extension assay (Olink®). Cytokines with 75% of values below the lower limit of detection of the assay were not evaluated. We performed an exploratory analysis of select pre-specified cytokines using a linear mixed model. Mean changes and 95% confidence intervals (CI) are presented with global p-values testing for a change in cytokine levels at any timepoint. Results: Urine samples were available for all 25 patients in the Phase I study. A total of 25 proteins on the panel were excluded due to low detection. Chemokines associated with T-cell trafficking (CXCL9, CXCL10, CXCL11) increased during induction treatment through 3 months of follow up and then returned to baseline after the completion of treatment (p0. 001 for each cytokine). IL-6 decreased after initiation of treatment and remained low through 12 months of follow up (-2. 7, 95% CI -3. 8, -1. 7; p0. 001). Notably, the one patient who had a recurrence also had a rise in IL-6 after an initial decline while on treatment. Conclusion: We found evidence that the addition of intravesical gemcitabine to BCG favorably augments the tumor microenvironment based on changes in urinary cytokine/chemokine profiles. Additional tumor and urinary correlatives are ongoing. Based on the the robust preliminary efficacy demonstrated in the ongoing phase I/II trial (NCT04179162), a prospective randomized controlled trial comparing GemBCG to BCG alone for BCG-exposed NMIBC is planned through the National Clinical Trial Network (Alliance A032303). Citation Format: Christopher D. Gaffney, Syed M. Alam, Jessica A. Lavery, Merve Basar, Neeta D'Souza, Christian Hernandez, Melissa McCarter, Patricia Moran, Kristen Stasi, Kara Worth, Daniel Sjoberg, Guido Dalbagni, Timothy Donahue, Sherri Donat, Dean Bajorin, Bernard H. Bochner, Alvin Goh, Judy Sarungbam, Hikmat Al-Ahmadie, Eugene J. Pietzak. Urinary cytokine profiles reflect rationale for treatment with gemcitabine and Bacillus Calmette-Guérin (BCG) in BCG-exposed high-risk non-muscle invasive bladder cancer (NMIBC) abstract. In: Proceedings of the AACR Special Conference on Bladder Cancer: Transforming the Field; 2024 May 17-20; Charlotte, NC. Philadelphia (PA): AACR; Clin Cancer Res 2024;30 (10Suppl): Abstract nr B007.
Gaffney et al. (Fri,) studied this question.