1084 Local administration of large surface area microparticle docetaxel is associated with anti-tumor immunomodulation across multiple tumor types

BackgroundLarge surface area microparticle docetaxel (LSAM-DTX) was developed for local administration to the tumor site where it continuously releases drug without significant systemic toxicity or immunosuppression. Post-administration, LSAM-DTX has been found within tumors for up to 50-days.1 To characterize immunomodulation following LSAM-DTX administration, immunophenotyping was performed in 3 tumor settings: before and after intramural-injection + instillation of LSAM-DTX at the site of transurethral resection of non-muscle invasive bladder cancer (NMIBC),2 after intratumoral administration in subcutaneous implanted syngeneic murine renal tumors (Renca), and after intratumoral administration ± systemic cytotoxic T-lymphocyte antigen blockade (anti-CTLA-4) in implanted syngeneic orthotopic murine metastatic luciferase-enabled breast tumors (4T-1-luc).3 Methods Table 1 describes tumor types and treatments. Fold-change data are reported for mIF. Changes in preclinical immune cell populations are reported if statistically significant (p