Arena Pharmaceuticals announced positive data from a planned interim analysis of the ongoing open-label extension of the Phase 2 trial of its investigational drug candidate ralinepag, a next-generation, oral, selective and potent prostacyclin receptor agonist in development for the treatment of pulmonary arterial hypertension (PAH).
This is an open-label extension study evaluating the long-term safety, tolerability and efficacy of ralinepag in 45 patients (85% of study completers) who completed the Phase 2 randomized study. In the extension study, patients originally randomized to ralinepag continued on active therapy (N=30); patients randomized to placebo switched to ralinepag (N=15). Key efficacy measurements include pulmonary vascular resistance (PVR) and 6-minute walk distance (6MWD).
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Patients who continued on ralinepag in the open-label extension had a median treatment duration of 1.8 years (range 1.2-3.4 years) at the time of right heart catheterization (RHC). In these patients, sustained improvements from baseline in the original study were observed for PVR (219 dyn*s*cm -5 median reduction, p = 0.002) and 6MWD (49.8 meters mean improvement; p = 0.003). Patients switching from placebo to active drug had a median ralinepag treatment duration of 1.4 years (range 0.9-2.3 years) at the time of RHC. In these patients, a similar magnitude of improvement was observed for PVR (214 dyn*s*cm -5 median reduction, p = 0.206) and 6MWD (69.8 meters mean improvement; p = 0.010). In both groups, these long-term changes in PVR and 6MWD were observed in a population where the majority of patients were already receiving dual combination PAH background therapy.
Adverse events (AEs) observed in this extension study were consistent with the known profile of prostacyclin therapies for the management of PAH, with headache and nausea being the most commonly reported. Among patients who continued ralinepag in the open-label extension, the incidence rate of AEs was lower relative to the randomized Phase 2 study, suggesting that AEs related to tolerability are reduced after initial drug titration.
"We are pleased with the long-term safety, tolerability and efficacy that ralinepag has demonstrated in the open-label extension of our Phase 2 trial. This is the first time an oral prostacyclin has shown durable, long-term improvements on hemodynamic and functional measures. Patients continuing ralinepag from the original study clearly maintained improvements in PVR and 6MWD. Those patients switching from placebo to ralinepag in this extension trial demonstrated a similar magnitude of effect on PVR and 6MWD, although the smaller sample size limits some of the statistical comparisons. These data reinforce our belief that PAH patients can truly benefit from ralinepag's improved receptor potency and extended pharmacokinetics," said Preston Klassen, MD, MHS, Executive Vice President, Research and Development and Chief Medical Officer of Arena. "Ralinepag has the potential to offer the pharmacokinetic and pharmacodynamic advantages of continuously infused IV prostacyclin with the ease of a once-daily oral tablet."
"It is encouraging to gain additional insight into the long-term safety and efficacy of ralinepag. I look forward to seeing data from the Phase 3 ADVANCE program and the effect that ralinepag may have when added to PAH standard of care," said Vallerie McLaughlin, M.D., Kim A. Eagle MD Endowed Professor of Cardiovascular Medicine at the University of Michigan and Director of the Pulmonary Hypertension Program1. "These data validate progress towards bringing a new therapeutic option to patients suffering from PAH, a devastating disease with significant unmet medical need despite available treatments."
Ralinepag (APD811) is a next-generation, oral, selective potent, once-daily IP receptor agonist intended for the treatment of pulmonary arterial hypertension (PAH). Arena discovered and developed this drug candidate internally. Ralinepag's potency on vasodilation, inhibition of proliferation of vascular smooth muscle cells, and inhibition of platelet aggregation, combined with an extended half-life, support its application as a potentially best-in-class agent for the treatment of PAH.