Regeneron Pharmaceuticals Inc.'s medicine garetosmab helped reduce bone lesions in patients with a type of rare bone disease called fibrodysplasia ossificans progressiva, or FOP, in a mid-stage study.
The Tarrytown, New York-based company evaluated garetosmab against placebo in a phase 2 trial, Lumina-1, to treat 44 adult patients with FOP.
FOP is a genetic disorder in which muscle tissue and connective tissue such as tendons and ligaments are gradually replaced by bones forming outside the skeleton, constraining movement.
The condition, which also affects children, is characterized by heterotopic ossification — the growth of bones in areas of the body where they do not normally exist — and cause lesions, or damage to tissues. FOP has no approved treatments, and there are about 800 patients diagnosed with the condition worldwide, Regeneron said in a Jan. 9 press release.
Regeneron said that following 28 weeks of treatment, garetosmab decreased total lesion activity in both new and existing bone lesions compared to placebo by 25%. In addition, there was about a 90% decrease compared to placebo in the number of new damage to tissues.
Regeneron added that treatment-emergent adverse events occurred in all the patients in both groups, and the majority of these events were mild to moderate in severity. Acute hemorrhage from the nostril and acne were among the adverse events that patients experienced.
The company, however, noted that one patient in the open-label portion of the trial — during which placebo-treated patients were crossed over to be treated with garetosmab — died due to trauma that was unrelated to treatment.
Regeneron plans to work with regulatory authorities for application submissions seeking the drug's approval.
The company added that detailed results — which will be used in regulatory filings — will also be presented at a future medical conference.
Regeneron is also planning for a clinical trial in children with FOP, an area that has seen Ipsen SA evaluate its drug palovarotene. In December 2019, the U.S. Food and Drug Administration partially halted certain studies of palovarotene — which was inherited by Ipsen following its $1.31 billion acquisition of Clementia Pharmaceuticals Inc. — in children due to safety concerns.