PB1023 is a recombinant GLP-1 analogue genetically fused to ELP biopolymer designed for use as a once-weekly treatment for hyperglycemia associated with type 2 diabetes. In a phase 2a multiple ascending dose study, PB1023 demonstrated a prolonged effect on glucose control, which was maintained between weekly doses of the drug.

PhaseBio subsequently conducted a multi-center phase 2b study in approximately 600 patients over 20 weeks to compare several doses of PB1023 against placebo and against an active comparator, Victoza® (liraglutide, Novo Nordisk). PB1023 was administered once per week, whereas Victoza® must be administered daily. Although PB1023 showed a significant reduction in HbA1C compared to placebo, the reduction was less than that seen with Victoza®.