October 9th, 2013

New Drug for Pulmonary Hypertension Approved by FDA

The FDA approved on Tuesday a new drug for pulmonary hypertension. Bayer HealthCare’s riociguat (brand name Adempas) was approved for two indications:

  1. the treatment of adults with persistent/recurrent chronic thromboembolic pulmonary hypertension (CTEPH) after surgical treatment or inoperable CTEPH to improve exercise capacity and WHO functional class
  2. the treatment of adults with pulmonary arterial hypertension (PAH) to improve exercise capacity, improve WHO functional class and delay clinical worsening

In an FDA press release, Norman Stockbridge, director of the Division of Cardiovascular and Renal Drug Products in the FDA’s Center for Drug Evaluation and Research, said that “Adempas is the first in its drug class approved to treat pulmonary hypertension and the first drug of any class to be shown to be effective for patients with CTEPH.” The drug was reviewed as part of the FDA’s priority review program, which provides for an expedited 6-month review of drugs that may offer major advances in treatment.

The drug will carry a Boxed Warning alerting patients and healthcare professionals that the drug should not be used in pregnant women because it can harm the developing fetus. Women will be able to receive the drug only through the Adempas REMS program, which will require them to comply with pregnancy testing requirements and be counseled regarding the need for contraception.

Riociguat is a soluble guanylate cyclase stimulator and is thought to have vasodilating, antiproliferative, and antifibrotic effects. The results of two phase 3 studies supporting the new indications were published in July in the New England Journal of Medicine. In August an FDA advisory panel unanimously recommended approval of the drug for the two indications. Last month the FDA granted an orphan drug designation for the indications.

Both forms of pulmonary hypertension are characterized by blockage of the pulmonary vasculature. Patients with pulmonary hypertension are at high risk for right ventricular failure and death. Even though there already were several approved therapies for pulmonary arterial hypertension, the yearly mortality rate remained high, at about 15%. No drugs were previously approved for chronic thromboembolic pulmonary hypertension, though a surgical procedure, pulmonary endarterectomy, could cure the disease when it was successful. However, pulmonary endarterectomy is a difficult procedure that should only be performed at a very few centers with experience performing the procedure.

CardioExchange’s John Ryan, a pulmonary hypertension researcher at the University of Utah, offered the following comment:

“It will be interesting to see where this fits in our treatment options of PAH. Prostacyclin therapy is used for patients with severe right heart failure and is first line in these patients. PDE5i and ERAs have been the oral treatment options for a lot of PAH providers in patients without overt right heart failure. Then if symptoms persist or if right heart failure develops, despite dual oral therapy, providers have been upescalating patients to prostacyclins. It is unclear if, now that riociguat is available, this agent will be introduced before opting for prostacylins. Currently, there is a delay in referral of PAH patients to specialist centers of about 14 months. If providers opt for ERA plus PDE5i plus riociguat before the introduction of prostacyclins, or referral to PH centers, this has the potential to postpone the introduction of prostacyclins in these sick patients. Therefore, the outcomes in these patients will need to be followed closely to see if such delays have an impact in morbidity and mortality in this population.”

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