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Briefing note: riociguat (Adempas)

What is riociguat used for?

Riociguat is a treatment for pulmonary arterial hypertension (PAH). Pulmonary arterial hypertension is a disease where the blood pressure in the blood vessels from the heart to the lungs is raised due to them being narrowed. This causes reduced blood flow to the lungs which makes any physical activity difficult. Riociguat is for use in World Health Organisation Functional Class (WHO FC) II to III PAH. Class II patients have slightly limited physical activity and Class III have more severely
limited physical activity.

How does it work?

Riociguat is the first member of a new class of medicines that stimulate an enzyme called soluble guanylate cyclase (sGC). This enzyme is involved in controlling the constriction of the blood vessels of the lungs. By stimulating sGC, riociguat causes the blood vessels to relax and widen. This increases blood flow and reduces the symptoms of PAH.

What has SMC advised?

SMC has accepted riociguat for restricted use for the treatment of adult patients with PAH with WHO FC II to III to improve exercise capacity. SMC has restricted it to use as a PAH-specific monotherapy as an alternative treatment option to endothelin receptor antagonist (ERA) monotherapy in adult patients with PAH of WHO FC II to III. It is restricted to initiation and prescribing by specialists in the Scottish Pulmonary Vascular Unit or by similar specialists.

What is the evidence to support this advice?

  • A study of patients with symptomatic PAH showed that patients treated with riociguat had improved exercise capacity (in terms of 6 minute walking distance) when compared with patients treated with placebo (a dummy medicine with no active treatment).
  • An economic analysis compared riociguat with endothelin receptor antagonists. There were a number of uncertainties with the analysis. However, as riociguat is an orphan medicine, SMC can accept greater uncertainty in the economic case.
  • This advice takes account of the views from a Patient and Clinician Engagement (PACE) meeting. Participants highlighted that riociguat would provide another treatment option for patients that may improve exercise tolerance resulting in greater independence which would have a positive impact on the quality of life of patients and their families.
  • Riociguat also met one of the criteria that SMC can take into consideration in reaching a decision (known as modifiers) as it is an orphan medicine (a medicine for a rare condition).

After considering all the available evidence, application of the orphan modifier and consideration of the output from the PACE meeting, SMC has accepted riociguat for restricted use in NHSScotland because it is an effective treatment that may offer additional patient benefits. This SMC advice is dependent upon the continuing availability of the PAS or a list price that is equivalent or lower.