Sohonos (palovarotene) is used for fibrodysplasia ossificans progressiva (FOP) to decrease the abnormal formation of bone in joints, muscles, tendons, and ligaments. Sohonos is FDA-approved to be used in adults, girls over 8 years old, and boys over 10 years years old who have FOP. 

Sohonos works by switching on the process that reduces bone formation by attaching to the retinoic acid receptor (gamma) and so improves symptoms of FOP.  Sohonos (palovarotene) is a retinoic acid receptor (gamma) agonist that belongs to a class of medicines known as retinoids.

Sohonos became the first FDA-approved medicine for FOP on 16 August 2023.  Approval was based on positive results from the Phase III MOVE trial, a multicenter open-label trial in adult and pediatric patients with FOP. Sohonos reduced the volume of new bone growth by 54%.

What is fibrodysplasia ossificans progressiva?

Fibrodysplasia ossificans progressiva is a rare connective tissue disease where the connective tissue, such as muscle, tendons, and ligaments, turns into bone tissue, either spontaneously or if the tissue has been damaged. This new bone that forms is called heterotopic ossification and eventually can cause joints to become permanently fused and progressively restricts the person's ability to move, and reduces life expectancy. FOP is caused by a mutation of the gene Activin A receptor, type I (ACVR1), which is responsible for the development and repair of the skeletal system.

Take Sohonos according to the instructions given to you by your healthcare provider.

• Take Sohonos capsules whole with food, at about the same time each day.
• If you are unable to swallow the capsule, the capsule contents may be emptied onto a teaspoon (5 mL) of soft food (such as apple sauce, low-fat yogurt, or warm oatmeal) and taken within 1 hour of opening
• Do not eat grapefruit or drink grapefruit juice during treatment with this medicine. Grapefruit may increase the levels of Sohonos in your blood.
• If you miss taking your capsule take it as soon as you remember. If the dose has been missed by more than 6 hours, the missed dose should be skipped, and next dose should be taken at the regular time. Do not take two doses at the same time or in the same day.
• Your healthcare provider may change your dose of Sohonos as needed if you get certain side effects.
• If you take more Sohonos than prescribed you may have symptoms such as severe headache, nausea or vomiting, drowsiness, irritability, and itching.

For adults and pediatric patients 14 years and older:

Recommended dosage is 5 mg 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 (20mg/10 mg flare-up treatment).

For pediatric patients under 14 years:

Weight-adjusted for daily and flare-up dosing. Recommended daily dosage range from 2.5 to 5 mg. See Full Prescribing Information for complete pediatric dosing 

Comments:

• Take Sohonos with food preferably at the same time each day
• Reduce the dose in the event of adverse reactions as appropriate.
• Sohonos is available as capsule in 1mg, 1.5mg, 2.5 mg, 5mg and 10mg strengths.

Tell your doctor or healthcare provider if you:

• have bone loss (osteoporosis), weak bones or any other bone problems.
• have or had mental health problems.
• have or have had kidney problems.
• have or have had liver problems.

Pregnancy

Sohonos can cause birth defects (deformed babies) if taken during pregnancy. Females should not take Sohonos if they are pregnant, they become pregnant, or are planning to become pregnant. See Warnings section above for more information.

Breastfeeding

Tell your doctor or healthcare provider if you are breastfeeding or plan to breastfeed. It is not known if Sohonos passes into your breastmilk. Breastfeeding is not recommended during treatment with Sohonos and for at least 1 month after the last dose of this medicine. Talk to your healthcare provider about the best way to feed your baby if you take Sohonos.

• Do not get pregnant while taking Sohonos. See Warnings section above
• Avoid excessive exposure to sunlight and ultraviolet lights (e.g., tanning machines). Sohonos may make your skin more sensitive to sunlight and ultraviolet light.
  You may burn more easily. You should use sunscreen and wear sunglasses and protective clothing that covers your skin to help protect against sunburn if you must be in the sunlight during treatment with this medicine.
• Sohonos may decrease your ability to see in the dark. Avoid driving at night until you know if Sohonos has affected your vision.
• Do not donate blood while taking this medicine and for 1 week after stopping.

Common Sohonos side effects

• dry skin
• swelling and small cracks in the corner of the mouth
• dry lips
• nausea
• hair loss
• muscle and joint pain
• itching
• dry eyes
• redness
• headache
• rash
• fatigue
• skin peeling
• drug eruption
• skin irritation.

Serious Sohonos side effects

Sohonos can cause serious side effects. See a Warnings section below about Sohonos causing birth defects and bone growth changes.

Other serious side effects include: 

Skin-related problems including dry skin, lips and eyes, hair loss, itching, redness, rash, and skin peeling.  You may be at increased risk of developing skin and soft tissue infections while taking Sohonos. If you develop these symptoms, your healthcare provider may tell you to use a moisturizer, sunscreen, or artificial tears.

Bone mineral density problems. Sohonos can cause a reduction in bone mineral density (bone thinning) which can increase the risk of fractures in adults and children. Your healthcare provider should check you for this during treatment with this medicine.

New or worsening mental health problems. Sohonos may cause new or worsening depression, anxiety, mood changes, and suicidal thoughts and behaviors. If you have a history of mental health problems, you may be at a higher risk of developing these side effects. Call your healthcare provider if you develop new or worsening mental health symptoms during treatment with Sohonos. Your healthcare provider should monitor you for signs of depression and refer you for appropriate treatment, if necessary.

Vision problems. Decreased vision in the dark (night blindness). You may have difficulty seeing at night or in low lit areas. Your healthcare provider should send you to see an eye specialist if you experience vision problems.

These are not all the possible side effects of Sohonos. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Warnings

Sohonos can cause birth defects (deformed babies) if taken during pregnancy. Females should not take Sohonos if they are pregnant, they become pregnant, or are planning to become pregnant.

Females who can become pregnant:

• You will be asked to take a pregnancy test 1 week before starting treatment with Sohonos, periodically during treatment, and 1 month after you stop treatment of this medicine.
• You must use effective birth control (contraception) starting at least 1 month before starting treatment with Sohonos, during treatment, and for 1 month after the last dose. Talk to your healthcare provider about birth control methods that may be right for you.
• If you become pregnant or think you may be pregnant during treatment with Sohonos, stop taking Sohonos and call your healthcare provider right away.
• Because Sohonos can cause birth defects, it is only for people who can understand and agree to carry out all instructions for pregnancy prevention.

Do not take Sohonos if you are allergic to medicines known as retinoids or any of the ingredients in Sohonos. See the bottom of this page for a full list of ingredients.

Sohonos can cause bone growth changes. Children may stop growing while taking Sohonos. Bone growth changes such as permanent early closure of the growth plate in growing children have happened with Sohonos. Your healthcare provider will closely monitor your child’s bone growth and height during treatment with Sohonos.

What should I tell my doctor before taking Sohonos?

Tell your doctor or healthcare provider if you:

• have bone loss (osteoporosis), weak bones or any other bone problems.
• have or had mental health problems.
• have or have had kidney problems.
• have or have had liver problems.

Pregnancy

Sohonos can cause birth defects (deformed babies) if taken during pregnancy. Females should not take Sohonos if they are pregnant, they become pregnant, or are planning to become pregnant. See Warnings section above for more information.

Breastfeeding

Tell your doctor or healthcare provider if you are breastfeeding or plan to breastfeed. It is not known if Sohonos passes into your breastmilk. Breastfeeding is not recommended during treatment with Sohonos and for at least 1 month after the last dose of this medicine. Talk to your healthcare provider about the best way to feed your baby if you take Sohonos.

What should I avoid while taking Sohonos? 

• Do not get pregnant while taking Sohonos. See Warnings section above
• Avoid excessive exposure to sunlight and ultraviolet lights (e.g., tanning machines). Sohonos may make your skin more sensitive to sunlight and ultraviolet light.
  You may burn more easily. You should use sunscreen and wear sunglasses and protective clothing that covers your skin to help protect against sunburn if you must be in the sunlight during treatment with this medicine.
• Sohonos may decrease your ability to see in the dark. Avoid driving at night until you know if Sohonos has affected your vision.
• Do not donate blood while taking this medicine and for 1 week after stopping.

How should I take Sohonos?

Take Sohonos according to the instructions given to you by your healthcare provider.

• Take Sohonos capsules whole with food, at about the same time each day.
• If you are unable to swallow the capsule, the capsule contents may be emptied onto a teaspoon (5 mL) of soft food (such as apple sauce, low-fat yogurt, or warm oatmeal) and taken within 1 hour of opening
• Do not eat grapefruit or drink grapefruit juice during treatment with this medicine. Grapefruit may increase the levels of Sohonos in your blood.
• If you miss taking your capsule take it as soon as you remember. If the dose has been missed by more than 6 hours, the missed dose should be skipped, and next dose should be taken at the regular time. Do not take two doses at the same time or in the same day.
• Your healthcare provider may change your dose of Sohonos as needed if you get certain side effects.
• If you take more Sohonos than prescribed you may have symptoms such as severe headache, nausea or vomiting, drowsiness, irritability, and itching.

Sohonos Dosing Information

For adults and pediatric patients 14 years and older:

Recommended dosage is 5 mg 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 (20mg/10 mg flare-up treatment).

For pediatric patients under 14 years:

Weight-adjusted for daily and flare-up dosing. Recommended daily dosage range from 2.5 to 5 mg. See Full Prescribing Information for complete pediatric dosing 

Comments:

• Take Sohonos with food preferably at the same time each day
• Reduce the dose in the event of adverse reactions as appropriate.
• Sohonos is available as capsule in 1mg, 1.5mg, 2.5 mg, 5mg and 10mg strengths.