OBJECTIVES: Pulmonary arterial hypertension (PAH) is a severe, progressive condition that can cause right ventricular dysfunction and cardiac failure. In the GRIPHON study, selexipag reduced the risk of the primary endpoint (composite of all-cause death or a PAH-related complication) compared to placebo. However, its cost effectiveness in Singapore remains unknown. An economic evaluation was undertaken to assess the cost effectiveness of selexipag as an add-on therapy, versus placebo, for treating PAH.

METHODS: A Markov cohort model with five health states was developed from the Singapore healthcare system perspective. Transition probabilities were derived from the GRIPHON study. In the absence of local estimates health state utilities were obtained from published literature, and direct costs were sourced from Singaporean public healthcare institutions. Selexipag was assumed to be discontinued on disease progression, and the impact of this assumption was tested in scenario analyses.

RESULTS: Compared to the placebo arm, patients treated with selexipag accrued more quality-adjusted life years (QALYs). This was mainly due to a reduction in disease progression, as no mortality benefit with selexipag was shown in the trial. They also accrued higher costs due to selexipag’s high treatment cost, despite costs averted due to fewer hospitalizations and subsequent treatment with epoprostenol. Using the local 2023 price for selexipag, the base case incremental cost-effectiveness ratio (ICER) was over SGD900,000 (USD668,385) per QALY gained compared with placebo. When an average of overseas prices was used, the ICER reduced to below SGD300,000 (USD222,795) per QALY gained. The ICER was highly sensitive to selexipag’s price. In the scenarios where patients were assumed to continue selexipag even after disease progression, the ICER increased by 25 to 35%.

CONCLUSIONS: At the current price, selexipag is unlikely to be cost effective for treating patients with PAH in Singapore, when compared to placebo.