Sotatercept for PAH Granted Orphan Designation from EC

In a recent press release, biopharmaceutical company Acceleron Pharma, Inc. (“Acceleron”) announced that its investigational drug candidate sotatercept received Orphan designation from the European Commission (EC) for the treatment of pulmonary arterial hypertension (PAH). While the drug previously received Priority Medicines status in Europe and both Orphan Drug and Breakthrough Therapy designations in the United States, this newest designation highlights a potentially efficacious treatment for European patients with PAH. However, sotatercept is not currently approved for use in PAH or any other conditions.


Licensed through an agreement with Bristol Myers Squibb (“BMS”), sotatercept is a reverse-modeling agent and selective ligand trap for the TGF-beta superfamily. The drug is designed to balance BMPR-II signaling; when this is imbalanced, it can spur the development and progression of PAH. Currently, sotatercept has been explored through the Phase 2 PULSAR clinical trial. Used in conjunction with other treatments, sotatercept helped improve pulmonary health. The treatment was found to be relatively safe and well-tolerated. Additionally, the drug is also being analyzed in the Phase 2 SPECTRA trial. Phase 3 clinical trials, such as STELLAR, ZENITH, and HYPERION, are being planned.

According to the European Medicines Agency (EMA), an estimated 30 million European citizens have a rare disease. The EMA describes Orphan designation as:

A status assigned to a medicine intended for use against a rare condition. The medicine must fulfil certain criteria for designation as an orphan medicine so that it can benefit from incentives such as protection from competition once on the market.

Once the EMA establishes an opinion on an application, that is passed along to the EC, who ultimately makes the decision to grant the designation. In this case, Orphan designation is given to drugs treating rare conditions affecting less than 5 out of every 10,000 people. Outside of 10 years of market exclusivity, Orphan designation also offers clinical trial assistance and scientific and research advice.

Pulmonary Arterial Hypertension (PAH)

Although family history plays a role in up to 20% of pulmonary arterial hypertension (PAH) cases, this chronic condition is more often caused by BMPR2 gene mutations. PAH is a progressive form of high blood pressure. Normally, oxygenated blood moves through the left side of the heart into the body. An additional circulatory system exists to remove deoxygenated blood from the heart via the pulmonary artery. However, with PAH, high blood pressure causes pulmonary arteries to harden or thicken, making it more difficult to force blood through. Typically, PAH affects females more than males, and specifically those between ages 30 and 60. Unfortunately, the 5-year survival rate for PAH sits at around 57%.

While many people with PAH are asymptomatic, especially at earlier stages, symptoms include:

  • Fatigue
  • Chest pain
  • Exercise intolerance
  • Shortness of breath / difficulty breathing
  • Fainting and dizziness
  • Ankle and leg swelling
  • Heart and liver enlargement
  • Cyanosis (bluish skin discoloration)
  • Heart palpitations
Jessica Lynn

Jessica Lynn

Jessica Lynn has an educational background in writing and marketing. She firmly believes in the power of writing in amplifying voices, and looks forward to doing so for the rare disease community.

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