FDA dishes out RPDDs for two bone-related drug candidates

The US Food and Drug Administration has granted the coveted Rare Pediatric Disease designation (RPDD) to two bone disease drugs, one from UK-based Mereo BioPharma (AIM: MPH) and the other to US company Innova Therapeutics.

For Mereo, whose shares shot up as much as 32% in early trading today, the RPDD is for its setrusumab, a treatment for osteogenesis imperfecta (OI).

Setrusumab is a fully humanized monoclonal antibody that inhibits sclerostin, a protein which inhibits the activity of bone-forming cells. OI is a genetic rare disorder with no approved treatments that is characterized by reduced bone mass and fragile bones that break easily. In Mereo’s Phase IIb ASTEROID study, setrusumab demonstrated a dose-dependent bone building effect and a trend of reduction in fractures in addition to being safe and well tolerated in adults with OI.