Safety and efficacy of rodatristat ethyl for the treatment of pulmonary arterial hypertension (ELEVATE-2): a dose-ranging, randomised, multicentre, phase 2b trial.

Background: The role of serotonin in pulmonary arterial hypertension has been extensively studied in recent decades, with preclinical data strongly indicating involvement in disease pathogenesis; however, clinical studies have yielded mixed results.

Methods: ELEVATE-2 was a phase 2b dose-ranging, randomised, double-blind, placebo-controlled, multicentre trial investigating rodatristat ethyl as a treatment for patients with pulmonary arterial hypertension. The study was conducted at 64 sites across 16 countries in Europe and North America. Eligible participants were aged 18 years or older, had pulmonary arterial hypertension with WHO functional class II or III symptom severity, and had received a stable dose and regimen of one or more pulmonary arterial hypertension treatments for at least 12 weeks. Participants were randomly assigned 1:1:1 to receive two placebo tablets, one placebo and one rodatristat ethyl 300 mg tablet, or two rodatristat ethyl 300 mg tablets twice daily using an interactive response system. Participants, investigators, site personnel, and sponsors were masked to treatment allocation. Participants who completed the 24 week treatment period were invited to continue in an open-label extension. The primary endpoint was percent change in pulmonary vascular resistance (PVR) from baseline to week 24. Primary efficacy analyses were conducted on the intention-to-treat population and analyses of harms were conducted in the safety population, which included all patients who received any amount of the study drug. This trial is registered with ClinicalTrials.gov, NCT04712669, and is now complete.

Findings: Between March 18, 2021 and Dec 13, 2022, 108 participants were enrolled and randomly assigned. 36 participants received placebo, 36 received rodatristat ethyl 300 mg, and 36 received rodatristat ethyl 600 mg twice daily. Overall, 85 (79%) of participants were female and 23 (21%) were male. The mean age was 52·8 years (SD 14·7) in the full analysis set. In the open-label extension phase, 62 (82%) of participants were female and 14 (18%) were male, and the mean age was 52·8 years (SD 14·7); this phase was terminated following sponsor review of unmasked main study results. Least-squares mean percent change in PVR from baseline to week 24 favoured placebo and was 5·8% (SE 18·1) for the placebo group, 63·1% (18·5) for the rodatristat ethyl 300 mg group, and 64·2% (18·0) for the rodatristat ethyl 600 mg group. Treatment-emergent adverse events (TEAE) were reported for 29 (81%) patients in the placebo group, 33 (92%) patients in the rodatristat ethyl 300 mg group, and all 36 (100%) patients in the rodatristat ethyl 600 mg group. TEAE leading to study discontinuation were reported for three (8%) patients in the placebo group, four (11%) patients in the rodatristat ethyl 300 mg group, and four (11%) in the rodatristat ethyl 600 mg group. There was one (3%) TEAE leading to death in the rodatristat ethyl 300 mg group.

Interpretation: Our results indicate that reducing peripheral serotonin concentrations via rodatristat ethyl has a negative effect on pulmonary haemodynamics and cardiac function in patients with pulmonary arterial hypertension. This finding suggests that manipulating this pathway might not be a suitable option for pulmonary arterial hypertension therapy.

Funding: Enzyvant Therapeutics (now Sumitomo Pharma America).