Arena Pharmaceutical’s Ralinepag Shows Promise in Treating PAH in Phase 2 Clinical Trial

Janet Stewart, MSc avatar

by Janet Stewart, MSc |

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Ralinepag and pulmonary arterial hypertension

Patients with pulmonary arterial hypertension (PAH) taking Arena Pharmaceuticals‘ next-generation therapy Ralinepag (APD811) showed significant improvements in blood flow and exercise capacity in a Phase 2 clinical trial.

Results of the study (NCT02279160) will be presented at the American College of Chest Physicians 2017 (CHEST) Annual Meeting, to be held Oct. 28 to Nov. 1, at the Metro Toronto Convention Centre in Toronto, Canada.

Ralinepag is a selective prostacyclin receptor (IP) agonist. Prostacyclin is normally produced in endothelial cells that line the walls of arteries and veins. It is a known vasodilator that widens blood vessels, allowing blood to flow through them more freely.

Ralinepag promotes the activity of prostacyclin, and it is taken orally, making it easier to use and tolerate compared to other prostacyclin receptor agonists.

The presentation at CHEST 2017 is titled “Hemodynamic Effects of the Oral Prostacyclin (IP) Receptor Agonist Ralinepag in Pulmonary Arterial Hypertension (PAH), and will be held during Session 4060 Late-breaking Abstracts, on Wednesday, Nov. 1 (3:45 pm EDT).

The trial enrolled 61 adults with PAH who were already receiving at least one PAH therapy. Participants were divided into two groups, with one group receiving Ralinepag while the other took a placebo. They were followed for 22 weeks, including a 13-week treatment period. Those who completed the 22-week period had the option to transition to an extension study.

Change in pulmonary vascular resistance (PVR; used in calculations of blood pressure, blood flow in vessels supplying the lungs) was the measure used to assess the efficacy of the drug. Also, the 6-minute walk distance (6MWD, the distance walked in 6 minutes, an evaluation of exercise capacity) was assessed.

Those receiving Ralinepag showed a significant change in PVR and improved 6MWD results compared to the placebo group. The number of adverse events was comparable to that found with treatments based on other prostacyclin receptor agonists.

Based on these positive results, Arena is planning a Phase 3 clinical trial program with ralinepag.

“These Phase 2 results are extremely compelling, particularly considering the contemporary patient population of our trial in which 65% of patients were already receiving dual background therapies and all patients were receiving at least one therapy,” Preston Klassen, MD, MHS, executive vice president, Research and Development and chief medical officer of Arena, said in a press release.

“We look forward to our upcoming discussions with the FDA and advancing into a Phase 3 clinical program,” Klassen added.

Ralinepag is an investigational drug and has not been approved by the FDA or any other regulatory agency in the world.