Riociguat for pulmonary arterial hypertension and chronic thromboembolic pulmonary hypertension

PURPOSE: The pharmacology, pharmacokinetics, clinical efficacy, safety, and role in therapy for riociguat are reviewed. SUMMARY: Riociguat is the first member of a new class of medications, soluble guanylate cyclase stimulators. Riociguat is indicated for patients with resistant or recurrent chronic thromboembolic pulmonary hypertension (CTEPH) after pulmonary endarterectomy who have World Health Organization (WHO) functional class IV pulmonary arterial hypertension (PAH) and in patients with inoperable CTEPH, regardless of WHO functional class, to improve exercise capacity and WHO functional class. Riociguat is indicated in patients with WHO functional class II PAH to improve exercise capacity, improve functional class, and delay clinical worsening. The mechanism of action of riociguat is within the nitric oxide pathway in the pulmonary vasculature. Clinical trials have demonstrated improvements in exercise capacity as measured by the six-minute walk distance test and in pulmonary arterial hemodynamics as measured by invasive pulmonary monitoring. Riociguat must be administered three times daily and requires dosage adjustments. Riociguat is a pregnancy category X drug and interacts with numerous medications. The two most serious adverse effects related to riociguat are hypotension and bleeding. Riociguat's role in the therapy of both PAH and CTEPH will be determined as more clinical experience and data are collected. Riociguat will likely cost approximately $90,000 annually. CONCLUSION: Riociguat is a soluble guanylate cyclase stimulator approved for the treatment of CTEPH and PAH. It can be considered first-line therapy for the treatment of CTEPH and should be considered as an alternative to phosphodiesterase type-5 inhibitors in patients with PAH.