Safety of locally administered large surface area microparticle paclitaxel and docetaxel in combination with standard of care cancer therapies

e15187 Background: The safety of local delivery of large surface area microparticle paclitaxel (LSAM-PTX) or docetaxel (LSAM-DTX) to solid tumors has been evaluated in Phase 1/2 trials across 156 subjects with 43% (67/156) on various concurrent standard of care (SOC) therapies. Local administration of LSAM-PTX or LSAM-DTX leads to a reduction in systemic drug exposure and drug-related adverse events (AE) and may reduce toxicities encountered in combination systemic treatment regimens. This report summarizes safety findings in subjects co-administered LSAM-PTX or LSAM-DTX and common SOC therapies for treatment of carcinomas. Methods: During the study follow-up periods, AE and serious AE (SAE) were coded (MedDRA 16.1 -23.1) and assessed (NCI CTCAE 3 - 5). Results: In 7 studies (median age 69 years (range 37-96), 61% male, 88% white) (Table), LSAM-PTX administrations occurred as follows: intraperitoneal (n = 31 subjects), intraprostatic (n = 17), and intratumoral (n = 72). A median of 1 cycle (range 1-6) of LSAM-PTX was administered. LSAM-DTX was injected once into bladder tissue after tumor resection followed by a median of 10 cycles (range 7-10) of intravesical instillation in 36 subjects. 59 subjects (median age 65 (range 48-86), 53% male, 88% white) received local LSAM-PTX and concomitant chemotherapy, immunotherapy, or radiation. Rates of subjects who had Grade 3 SAE possibly related to LSAM-PTX were 29%, 24%, 16%, 6.7% and 5.0% in paclitaxel, carboplatin, 5-FU, nab-paclitaxel, and gemcitabine combinations, respectively. Grade 4 SAE possibly related to LSAM-PTX were found in 1 subject each co-administered pembrolizumab (13%), carboplatin (5.9%), and paclitaxel (7.1%). Subjects treated with 5-FU, gemcitabine, and nab-paclitaxel reported no related Grade 4 SAE. No Grade 5 SAE were deemed possibly related to LSAM-PTX. 8 subjects (median age 78 (range 54-89), 100% male, 88% white) received local LSAM-DTX therapy in combination with SOC therapies. No Grade 3-5 AE were reported with LSAM-DTX in combination with gemcitabine, carboplatin, pembrolizumab, avelumab or radiation. Conclusions: Local treatment of solid tumors with LSAM-PTX or LSAM-DTX has the potential to overcome some limitations of SOC therapies by increasing tumor dwell time and reducing systemic toxicities which are often exacerbated in combinatorial treatment regimens. Clinical trial information: NCT00666991 , NCT03636256 , NCT03077659 , NCT04221828 , NCT03029585 , NCT03077685 , NCT04314895 . [Table: see text]