Sotatercept is type of drug known as an activin signaling inhibitor. Activin is a protein that can cause smooth muscle cells to increase in number. Some people with PH have too much activin signaling, which overproduces smooth muscle cells in the pulmonary arteries. Overproduction causes blood vessels to narrow. Activin signaling inhibitors counteract overgrowth of smooth muscle in the blood vessels of the lungs.

Note: Sotatercept is a biologic drug, which means it is made from living systems, such as a microorganism or plant or animal cell, in a carefully controlled facility or lab. Biologics differ from conventional medications, such as aspirin, which typically are created by combining chemicals. Biologic drugs have been part of medical treatment for a long time to treat cancer, rheumatoid arthritis, psoriasis inflammatory bowel disease and other diseases.

Sotatercept is delivered through an injection under the skin in the abdomen or upper thigh every three weeks. The injection must be at least two inches away from the belly button if the injection goes in the abdomen.

Sotatercept is available in two strengths: 45- or 60-mg vials.

Sotatercept shouldn’t be injected into areas that are tender, red, bruised, hard or have scars or stretch marks.

If you take sotatercept, make sure you rotate injection sites to ensure you skin stays healthy and can absorb the medication.

Starting sotatercept

The recommended starting dose is 0.3 mg per kg (based on body weight). Depending on how well you tolerate the medication, your dose might increase every three weeks until you reach the 0.7 mg recommended target dose.

Before starting your first dose of sotatercept, your doctor will order a complete blood cell count test to check your levels of hemoglobin (protein in red blood cells that carries oxygen) and platelets (blood cells that help blood clot).

You will need a complete blood cell count test every 21 days before each dose. Your sotatercept dose might need to be adjusted if your hemoglobin level is too high and/or platelet count is too low. Your doctor might delay your next injection or change the dose.

Note: Laboratory monitoring is recommended for at least the first five doses. You might need more frequent lab tests if your results are abnormal.

Storage and handling

Store Winrevair vials in the refrigerator at 36°F to 46°F (2°C to 8°C). Make sure they are in the original cartons to protect from light. Do not freeze. Keep the kit in the refrigerator until you’re ready to use. An unused kit can be out of the refrigerator for (up to 25°C/77°F) up to 24 hours.

Sotatercept has limited distribution, which means you can’t fill the prescription at a local pharmacy. Your insurance company might need to approve this prescription before you start treatment. A specialty pharmacy specified by your insurance plan will ship the medicine to your home.

You can start sotatercept at home or in the clinic (bring your drug supply to your appointment). A health care provider or nurse will show you or your caregiver how to mix, prepare, measure and inject sotatercept. If you start at home, your health care provider can request a nurse from the specialty pharmacy to see you at home to start treatment.

The most common side effects include:

• Headache
• Nose bleeds
• Rash
• Diarrhea
• Dizziness
• Redness
• Small blood vessels that look like pink or red lines on the skin (telangiectasia). They also can occur in the gastrointestinal mucosa, which can increase the risk of gastrointestinal bleeding.

Sotatercept might cause serious side effects, including:

• Increased hemoglobin levels in the blood. This can increase your risk of blood clots.
• Severely low platelet levels in the blood. This can increase your risk of bleeding and/or bruising.
• Serious bleeding accompanied by vomiting blood or vomit that looks like coffee grounds.
• Dizziness or weakness.
• Pink/brown/cola-colored urine.
• Red or black stools that look tarry.
• Persistent abdominal cramps.
• Severe back pain.
• Coughing up blood or blood clots.
• Persistent headaches.
• Abnormal menstrual bleeding. Tell your healthcare provider if you develop any bleeding.

Note: Sotatercept may impair female and male fertility, as shown in animal studies. If you are concerned about your ability to have children, talk to your health care provider.

Certain patient populations must take precautions while taking riociguat, while others should avoid it. Learn about who can and who shouldn’t take this medication:

Pregnant and breastfeeding women

Sotatercept can harm a fetus if administered to a pregnant woman. Tell your health care provider if you are pregnant or planning to become pregnant. If you are a woman of child-bearing age, your provider should order a pregnancy test before you start taking sotatercept. You should use at least one form of birth control while taking sotatercept and for at least four months after your final dose.

Contact your provider right away if you become pregnant or if you think you may be pregnant while taking sotatercept.

There is no data on the presence of sotatercept in human milk, so you breastfeeding isn’t recommended.

Children and teens

The safety and effectiveness of sotatercept haven’t been established for patients younger than 18.

Other considerations

Kidney or liver disease aren’t conditions that prevent you from taking sotatercept.

Allergic reactions to this medication are possible but not likely. Any medication can cause side effects or sensitivities. Check with your doctor if you experience a rash or throat tightening.

Sotatercept can be taken with other prescribed PAH treatments. Most participants in the STELLAR clinical trial were taking either three or two other drugs for PAH. Forty percent were receiving prostacyclin infusion therapy.

No noted interaction has been reported for any other drugs.