Arena Pharma Begins Dosing PAH Patients with Ralinepag in Phase II Study

San Diego, California-based biopharmaceutical company Arena Pharmaceuticals, Inc. just announced they have begun dosing patients in a Phase II clinical program for ralinepag, an orally available, non-prostanoid prostacyclin (IP) receptor agonist, formulated for the treatment of pulmonary arterial hypertension (PAH).

Ralinepag has performed favorably in previous preclinical and clinical studies, and demonstrated a positive safety profile when dosed once or twice a day. The US Food and Drug Administration recently granted it an orphan drug status for PAH. PAH is a serious, progressive cardiopulmonary disease that can greatly limit one’s activities of daily living, and without proper and prompt treatment, can irreversibly progress to right side heart failure. According to the US Registry to Evaluate Early and Long-term PAH Disease Management (REVEAL), the five-year survival rate is 57% from diagnosis.

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“An intriguing component of this compound is the smooth peak-to-trough ratio, which may potentiate efficacy and minimize toxicity relative to currently available therapies,” said Lewis J. Rubin, M.D., the Emeritus Professor of Medicine at University of California, San Diego, School of Medicine. “This clinical trial should help to further elucidate how ralinepag’s intrinsic properties translate to its efficacy and safety profile.”

This randomized, double-blind, placebo-controlled Phase II study will run for 22 weeks, and aims to evaluate ralinepag’s effects on hemodynamics and exercise tolerance, along with safety and tolerability in a sample of 60 PAH patients. The study’s initial 9 weeks will be spent titrating the drug to suit each subject’s tolerance. Once tolerance level is determined, the subject will continue to be dosed for the remaining weeks.

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“We believe ralinepag offers promise in the IP receptor class of molecules given its oral availability, long plasma half-life, and high selectivity and potency in vitro,” said Jack Lief, Arena’s President and Chief Executive Officer. “In conjunction with our other clinical-stage programs, this compound further enhances our optimism about Arena’s value drivers.”

Recent updates on pulmonary hypertension:

Fellow drug development company, Actelion Ltd., recently filed for a New Drug Application (NDA) with the US Food and Drug Administration for novel PAH treatment Uptravi® (selexipag) — an orally available IP prostacyclin receptor agonist. The NDA was filed along with encouraging findings from a pivotal Phase III GRIPHON study that involved 1,156 PAH patients, which showed selexipag’s ability to lower the risk of a morbidity/mortality event by 39 percent, compared to a placebo.