Palovarotene is in clinical development for episodic and chronic use in the prevention of heterotopic ossification (HO) in patients with fibrodysplasia ossificans progressiva (FOP). FOP is a disabling condition, caused by the formation of bony bars within the muscles of the body (HO). This bone formation is usually first noticed in early childhood as a series of hard lumps in the neck or along the spine. These lumps, which may be tender, gradually shrink in size as the affected muscles are replaced by bone. The appearance of bony lumps in muscles is usually spontaneous but can also be provoked by any injury to the muscles.
Palovarotene is an oral, once-daily medicine which attaches to a receptor in cells, called the retinoic acid receptor gamma, switching on processes that reduce bone formation. If licensed, palovarotene has the potential to prevent HO in patients with FOP, a condition for which the only available treatments are for symptomatic relief.
Garetosmab is in clinical development for the prevention of abnormal bone formation, outside of the normal skeleton (heterotopic ossification), and soft-tissue flare-ups in patients with fibrodysplasia ossificans progressiva (FOP). FOP is a very rare disease caused by a mutation in the gene ACVR1. The mutation results in the formation of unwanted bone in muscles, tendons, and ligaments throughout the body. Abnormal, misplaced and mis-shapen (heterotopic) bone can bridge across joints causing immobility, scoliosis, and other deformities. Patients usually require a wheelchair by the time they reach their 20s. Death often results in the 40s from complications, such as pneumonia, heart failure and loss of mobility in the chest, neck and jaw.