Riociguat (Adempas) approved for PAH and CTEPH (pulmonary hypertension)

Riociguat (Adempas) Gets FDA Indications for Pulmonary Hypertension

That was fast. The US Food and Drug Administration (FDA) approved riociguat (brand name Adempas, by Bayer) for the treatment of pulmonary arterial hypertension (PAH) and the treatment of chronic thromboembolic pulmonary hypertension (CTEPH), on October 8 2013.

Adempas is the first of a class of drugs for pulmonary hypertension called soluble guanylate cyclase (sGC) stimulators. Riociguat is a vasodilator that enhances the actions of nitric oxide on sGC, and stimulates sGC directly. This relaxes pulmonary arterioles, increases blood flow and reduces pulmonary vascular resistance and pulmonary artery pressures.

Riociguat got an FDA indication for patients with chronic thromboembolic pulmonary hypertension (CTEPH) after pulmonary thromboendarterectomy or who cannot undergo the potentially curative surgery. This category of pulmonary hypertension is also called WHO Group IV.

Adempas also received an indication for pulmonary arterial hypertension (PAH) more generally (WHO Group I), in order to improve exercise capacity, improve WHO functional class, and delay clinical worsening.

Riociguat's safety and effectiveness for treatment of CTEPH were established in a clinical trial published in the New England Journal of Medicine in 2013. 261 participants were randomized to Adempas, up to 2.5 mg three times daily, or placebo. After 16 weeks, riociguat improved 6-minute walk distance an average of 46 meters (about 150 feet) more than the placebo group.

Riociguat as a treatment for pulmonary arterial hypertension was published in the same issue of NEJM, after 443 participants randomized to Adempas 1.5 mg or 2.5 mg improved their 6 minute walk distance by a mean of 36 meters (about 118 feet) farther than placebo-treated patients.

Adempas is teratogenic and has a black box warning against use in pregnant women; women can only receive riociguat through a special risk mitigation program including pregnancy testing and contraception counseling.

Common side effects in patients treated with Adempas during clinical trials included headache, dizziness, gastrointestinal intolerance, and peripheral edema.

The FDA approved riociguat under an expedited 6-month review of drugs that represent potentially significant advances in treatment. Riociguat's approval was expected, since an FDA advisory committee voted unanimously this summer to recommend approval of Adempas for the above indications.

"FDA approves Adempas to treat pulmonary hypertension," FDA website.