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  1. News & Events for Human Drugs

FDA approves first treatment for Fibrodysplasia Ossificans Progressiva


The U.S. Food and Drug Administration (FDA) has approved Sohonos (palovarotene) capsules for reduction in the volume of new heterotopic ossification (extra-skeletal bone formation) in adults and children aged 8 years and older for females, and 10 years and older for males with fibrodysplasia ossificans progressiva. Sohonos is the first drug approved for patients with fibrodysplasia ossificans progressiva.

Adults and pediatric patients 14 years and older should take 5 mg of Sohonos once daily, with an increase in dose at the time of a flare-up to 20 mg once daily for 4 weeks, followed by 10 mg once daily for 8 weeks for a total of 12 weeks (20/10 mg flare-up treatment). Patients under 14 years, based on their body weight, should take from 2.5 to 5 mg of Sohonos.

Disease or Condition

Fibrodysplasia ossificans progressiva is a rare, autosomal dominant disease where connective tissue such as muscle, tendons and ligaments gradually turn into bone tissue, causing limited movement, deformities and severe disability.


The safety and effectiveness of Sohonos was evaluated in clinical studies that enrolled a total of 164 subjects with fibrodysplasia ossificans progressiva, including 139 subjects in the indicated population of females, aged 8 years and above and males, aged 10 years and above (8/10 years and older). Most of the subjects received open label treatment with the chronic daily/flare-up regimen, consisting of 5 mg daily dosage of oral Sohonos with a 20/10 mg dosage as needed for 12 weeks at the time of flare-up (4 weeks of 20 mg once daily followed by 10 mg once daily for 8 weeks), with all doses reduced by weight in subjects who were less than 90% skeletally mature. The mean age of these subjects was 19 years (range 8 to 61 years); 51% were male.

Safety Information

Sohonos contains a boxed warning for embryo-fetal toxicity and premature epiphyseal closure (early closure of bone growth) in growing pediatric patients. Healthcare providers should verify that people who can become pregnant are not pregnant prior to beginning treatment and periodically during therapy. Monitoring linear growth in growing pediatric patients is also recommended. Before taking Sohonos, all growing pediatric patients should undergo skeletal maturity baseline assessments. Continued monitoring is recommended every 6 to 12 months until patients reach skeletal maturity or final adult height.

Sohonos comes with warnings and precautions: Sohonos is associated with dry skin, lip dry, pruritis, rash, alopecia, erythema, skin exfoliation, and dry eye; therefore prevention or treatment with skin emollients, sunscreen, artificial tears and dosage reduction may be required in some patients. Sohonos is associated with metabolic bone disorders, and decreased vertebral bone mineral content and bone density may occur; therefore, spinal fracture should be assessed periodically using radiologic methods. Sohonos is associated with depression, anxiety, mood alterations and suicidal thoughts and behaviors; therefore, patients should contact their healthcare provider if new or worsening symptoms develop. Sohonos is also associated with night-blindness and can make driving at night hazardous.

The most common adverse reactions include dry skin, lip dry, arthralgia, pruritis, pain in extremity, rash, alopecia, erythema, headache, back pain, skin exfoliation, nausea, musculoskeletal pain, myalgia, dry eye, hypersensitivity, peripheral edema, and fatigue. See the full prescribing information for all risks associated with Sohonos.


Sohonos received a priority review, fast track designation and breakthrough therapy designation for this indication.

FDA granted this approval to Ipsen Biopharmaceuticals, Inc.

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