Translating a Preclinical Hydrogel Platform into a Human Therapeutic for Delivering Targeted Low-Dose Anti-CTLA-4.

Systemic administration of antibodies that target immune checkpoint inhibitor pathways is a highly effective approach to cancer immunotherapy, but systemic toxicity can limit clinical utility. In preclinical testing, a peri-tumor injection of a low dose of hydrogel-encapsulated cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) antibody was shown to selectively activate T cells in tumor-draining lymph nodes, induce tumor infiltration by cytotoxic T cells, and result in tumor regression, protective immunity, and long-term survival. In contrast to systemic therapy, there was limited systemic exposure or risk for autoimmune toxicity. The current study focuses on translating this platform into a biocompatible human therapeutic. The hydrogel matrix was reformulated using a low-molecular-weight hyaluronic acid. A recombinant human hyaluronidase (rHuPH20) was incorporated to promote lymph node targeting and self-resorbing features. Formulations were optimized to operate at neutral pH and with gelation kinetics allowing a 5 to 10 min administration window. Performance features were assessed including the capacity to encapsulate human IgG or ipilimumab antibody at proposed therapeutic doses (1-15 mg/mL), impact of rHuPH20 and antibody on rheologic properties and three-dimensional microstructure, and payload delivery profiles in vitro and in vivo. Results confirm the capacity for this unique hydrogel platform to be adapted for human testing.