Riociguat: Something new in pulmonary hypertension therapeutics?

Pulmonary hypertension (PH) continues to be a disease that is associated with woeful outcomes. The search for an ideal drug molecule for PH led to the discovery of riociguat, which is a first-in-class drug molecule that activates soluble guanylate cyclase. We conducted a systematic literature search using databases such as PubMed, Science Direct, Springer, Cochrane Reviews and Google Scholar to gather evidence generated from published clinical trials on the efficacy, safety, pharmacokinetics and regulatory status of riociguat. CHEST-1 and the PATENT-1 were phase-3 pivotal clinical trials that showed that riociguat was able to significantly improve the 6-min walk distance with 16 weeks of therapy as compared with the placebo arm. The drug also showed improvement in secondary outcome measures such as improvement in the pulmonary vascular resistance, N-terminal pro-brain natriuretic peptide levels, World Health Organization functional class, time to clinical worsening and Borg dyspnea score. The drug had a modest safety profile, with hypotension being the most bothersome adverse effect. These findings led to various regulatory agencies around the world granting approval for riociguat for the treatment of pulmonary arterial hypertension (PAH) and inoperable chronic thromboembolic pulmonary hypertension (CTEPH). The entry of a new class of drug for PAH and CTEPH therapy portends some hope for patients with a disease that is traditionally linked with a poor prognosis.