Arena’s CEO Leaves Mast’s Board as Both Companies’ Experimental PAH Therapies Continue To Advance

The progress of two promising experimental PAH therapies has led one of the two drug development companies working on them to part ways with a board member in order to avoid a conflict of interest. Mast Therapeutics, Inc. recently announced the resignation of Jack Lief from its board of directors. Mr. Lief, who had been serving as a board member at Mast, is also the president and CEO of Arena Pharmaceuticals, Inc. Since both companies are actively developing treatments for pulmonary arterial hypertension, Lief, who was becoming increasingly associated in the development of both promising PAH therapies, decided to recuse himself from Mast’s board.

Mast is focused on using its unique molecular adhesion and sealant technology (MAST) platform to create new therapeutic options to address sickle cell disease, heart failure and arterial disease. Its leading product candidate to treat PAH, AIR001, has already been tested in phase I and II clinical studies and is now being studied as a treatment for heart failure with preserved ejection fraction (HFpEF).

Arena is working on an investigational treatment for vascular diseases such as PAH as well. The company’s experimental therapy Ralinepag is an orally available agonist of the prostacyclin (IP) receptor that was discovered and developed in-house by Arena.

“I would like to thank Jack for his many important contributions and exceptional service since he joined Mast’s Board in 2006,” said the CEO of Mast, Brian M. Culley. “Our Company has greatly benefitted from his leadership as Chair of the Board and his extensive experience in our industry. We appreciate Jack’s willingness to remain on the Board into the third quarter to assist in identifying and evaluating a suitable replacement who can help guide our company.”

Mast’s AIR001 (sodium nitrite) is an inhalation solution delivered via nebulizer for the treatment of PAH, which has revealed overwhelmingly positive results that were presented by the company last year. All doses of AIR001 were well-tolerated by patients and provided improvements in clinically relevant health parameters. In addition, the drug was granted orphan drug status by the FDA and the European Medicines Agency, which may facilitate progression through the three clinical trial phases while evaluating fewer patients.

Arena’s Ralinepag, which also holds FDA orphan drug designation for the treatment of PAH, has performed favorably in previous preclinical and clinical studies, and demonstrated a positive safety profile when dosed once or twice a day. The company began dosing PAH patients in its phase II clinical program last January.

Both companies are expected to provide encouraging, new options to improve treatment of PAH, which can greatly limit patients’ ability to perform even simple, daily activities. There is currently no cure for the disease and without proper and prompt treatment, it 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 just 57% from the time of diagnosis.