Subcutaneous Injection Performance in Yucatan Miniature Pigs with and without Human Hyaluronidase and Auto-injector Tolerability in Humans

Recombinant human hyaluronidase PH20 (rHuPH20) facilitates subcutaneous (SC) delivery of co-administered therapeutic agents by locally and transiently degrading hyaluronan in the SC space, and can be administered with therapeutics using a variety of devices. Two SC delivery studies were carried out to assess auto-injector (AI) performance, each in 18 Yucatan miniature pigs. Abdominal injections were administered using three auto-injectors of 1 mL (AI1) and 2 mL (AI2 and sAI2) with different injection speeds and depths (5.5–7.5 mm) and two pre-filled syringe (PFS) devices of 1 and 2 mL. The injection included a placebo buffer with and without rHuPH20 to evaluate the effect of rHuPH20 on SC injection performance. The feasibility of using similar devices to deliver a placebo buffer in humans was investigated. rHuPH20 was not studied in humans. In miniature pigs, postinjection swelling was evident for most PFS/AI injections, particularly 2 mL. Swelling heights and back leakage were typically lower with rHuPH20 co-administration versus placebo for most device configurations (1 or 2 mL PFS or AI). Auto-injections with versus without rHuPH20 also resulted in reduced swelling firmness and faster swelling resolution over time. Slow injections with rHuPH20 had shorter and more consistent injection time versus placebo. In humans, minimal injection site swelling and negligible back leakage were observed for 2-mL injections of placebo, while more erythema was observed in humans versus miniature pigs. Even at high delivery rates with PFS or AI, the addition of rHuPH20 resulted in improved SC injection performance versus placebo in miniature pigs.