Progression of FOP is characterized by episodic yet cumulative heterotopic ossification (HO) of certain skeletal muscles, tendons, ligaments, and fascia. Without effective treatment, the abnormal conversion of these tissues into histologically “normal” bone leads to fixation of joints and progressive immobility. Loss of mobility is common by age 20s to 30s, necessitating wheel chair use and long-term care (Kaplan, 2010).
While HO lesions can be provoked by some external trauma, HO lesions with no identifiable cause have also been documented.
Taken together, our in vitro and in vivo studies have shown that: (i) the R206H mutation permits activin A to activate the ACVR1 receptor and signal through BMP pathways that activin A would not ordinarily utilize, (ii) this abnormal signaling leads to HO in ACVR1[R206H] mice, and (iii) blockade of activin A may prevent the development and progression of HO.
There are no approved treatments for HO in people with FOP. Clinical management of FOP is largely avoidance of injury and supportive care once injury or disability occurs. Steroids and nonsteroidal anti-inflammatory drugs (NSAIDs) may be used to treat signs and symptoms of inflammation (e.g. pain, swelling, joint stiffness). Underscoring the importance of early diagnosis, resection of the heterotopic bone most often results in another more aggressive episode of HO and should be avoided (Huning, 2014).
Corticosteroids, NSAIDs, and immune suppressive drugs, among others, have been reported to have clinical benefits based on anecdotal evidence. However, the rarity, variable severity, and fluctuating clinical course of the disease render these claims uncertain (Kaplan, 2011).
We are interested in hearing from and collaborating with licensed medical professionals who care for people with FOP. You can register your interest in working with us by clicking here.
For a list of clinical trials relating to FOP, please refer to
Licensed medical professionals may indicate interest in participating in Regeneron’s FOP clinical research program by contacting our Medical Information Department on 1-844-MID-REGN (1-844-643-7346) Monday through Friday 8am - 8pm EST or by filling out the form below.
Scientists may indicate interest in collaborating with Regeneron in FOP research by contacting our Medical Information Department on 1-844-MID-REGN (1-844-643-7346) Monday through Friday 8am - 8pm EST or by filling out the form below.
Licensed medical professionals and scientists may request specific information about FOP and Regeneron’s FOP program by contacting our Medical Information Department on 1-844-MID-REGN (1-844-643-7346) Monday through Friday 8am - 8pm EST or by filling out the form below.