Sotatercept
Pulmonary arterial hypertension drugs (endothelin receptor antagonists and prostacyclins)
Pulmonary arterial hypertension drugs (endothelin receptor antagonists and prostacyclins)Pregnancy: avoid
Avoided in pregnancy: a pregnancy test is done first and effective contraception is used during treatment and for months after the last dose; breastfeeding is avoided.
An injected activin-signalling inhibitor for pulmonary arterial hypertension. It traps growth factors that drive vessel remodelling; it raises haemoglobin.
Quick facts
- Group
- Pulmonary arterial hypertension drugs (endothelin receptor antagonists and prostacyclins)
- Target
- Activin A and related ligands (GDF8, GDF11), trapped by an ActRIIA–Fc fusion protein
- Used for
- Pulmonary arterial hypertension
- Key effects
- Headache · Nosebleeds · Spider veins
- Monitor
- Bleeding signs · Pregnancy test before starting
- ATC
- C02KX06
No doses: the clinician sets them by the current guideline.
Mechanism of action
Sotatercept is a fusion protein made of the extracellular domain of the activin receptor type IIA joined to an antibody Fc fragment. It acts as a 'ligand trap', binding activin A, GDF8 and GDF11 before they reach their receptors. In pulmonary arterial hypertension, too much activin signalling (SMAD2/3) and too little BMPR2 signalling (SMAD1/5/8) drive cell growth in small pulmonary arteries; trapping the ligands rebalances these pathways and can reverse vessel remodelling rather than only dilating vessels. Trapping the same ligands also stimulates red-cell production.
- ActRIIA–Fc fusion traps activin A, GDF8, GDF11
- Less SMAD2/3 pro-proliferative signalling
- Balance with BMPR2 signalling is restored
- Pulmonary arterial remodelling regresses
Indications
- Pulmonary arterial hypertension in adults, added to background therapy, to improve exercise capacity and delay worsening Pulmonary hypertension and cor pulmonale →
Adverse effects
Common
- Headache, dizziness
- Nosebleeds
- Spider veins (telangiectasia)
- Rash or skin redness, easy bruising
- Diarrhoea
Contraindications
- Hypersensitivity to sotatercept
- Doses are delayed when haemoglobin is too high or platelets are too low
Key interactions
- Anticoagulants and antiplatelets
- More risk of bleeding when platelets fall.
What is monitored
- Haemoglobin and platelet count before doses, especially early
- Bleeding signs; telangiectasia
- Pregnancy test before starting
- Exercise capacity and PAH symptoms
Administration and safety
- Subcutaneous injection every three weeks; patients or carers are trained to prepare and inject it at home.
- Blood tests decide whether each dose is given, delayed or changed.
- It is added to, not a replacement for, existing PAH medicines.
Pregnancy and breastfeeding
Avoided in pregnancy: a pregnancy test is done first and effective contraception is used during treatment and for months after the last dose; breastfeeding is avoided.
Nursing care
- Before each dose early in treatment: check haemoglobin and platelets as ordered.
- Teach to report nosebleeds, blood in urine or stools, coughing blood or heavy periods.
- Confirm a negative pregnancy test and effective contraception.
- Teach injection technique and safe sharps disposal.
Pharmacokinetics
- Absorption
- Subcutaneous injection every three weeks.
Test yourself
Think of the answer, then tap the question to see it.
What kind of molecule is sotatercept?
A fusion protein of the activin receptor IIA extracellular domain with an Fc fragment, acting as a ligand trap.
How does sotatercept differ from classic PAH vasodilators?
It targets the growth signalling that remodels pulmonary arteries (activin/BMPR2 balance) instead of only dilating them.
Which two blood values are checked before doses?
Haemoglobin (it can rise) and platelets (they can fall).
Connections
Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.
Sources: Sotatercept-csrk Injection: MedlinePlus Drug Information (MedlinePlus (U.S. National Library of Medicine), 2024); Sotatercept: A novel therapeutic approach for pulmonary arterial hypertension through transforming growth factor-β signaling modulation (World Journal of Methodology, via PubMed Central, 2025); ATCDDD - ATC/DDD Index (WHO Collaborating Centre for Drug Statistics Methodology, 2026).
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Representative model, for educational purposes only.