Selten Pharma, a privatively held biopharmaceutical company focused on the development and commercialization of therapies for the treatment of rare diseases, has announced its lead compound tacrolimus (SPI-026) has been granted Orphan Drug designation by the FDA for the treatment of pulmonary arterial hypertension (PAH).

Leo Gu, Ph.D., co-CEO and president of Selten Pharma, said, "We are pleased to receive Orphan Drug Designation for SPI-026, which highlights the significant need for new medications for patients suffering from PAH. We greatly appreciate the FDA's support of our efforts to evaluate our SPI-026 program for the treatment of PAH. The results of the proof-of-concept, safety and tolerability study in this indication have been very encouraging."

"We are excited to begin the phase IIb clinical trial of SPI-026, which we believe has the potential to be the first disease-modifying treatment for patients with this life threatening disease. SPI-026 has been shown to activate the BMPR2 pathway and possibly could even reverse the effects of the disease," said Narinder S. Banait, Ph.D., J.D., co-CEO and general counsel of Selten Pharma.

Orphan Drug designation is granted by the FDA Office of Orphan Products Development (OOPD) to novel drugs or biologics that treat a rare disease or condition affecting fewer than 200,000 patients in the U.S. The designation provides the drug developer with a seven-year period of U.S. marketing exclusivity, as well as tax credits for clinical research costs, the ability to apply for annual grant funding, clinical research trial design assistance and waiver of Prescription Drug User Fee Act (PDUFA) filing fees. The OOPD also works on rare disease issues with the medical and research communities, professional organizations, academia, governmental agencies, industry, and rare disease patient groups.

PAH is a life-threatening disease characterized by elevated blood pressure in the pulmonary arteries. Severe constriction of the blood vessels in the lungs leads to very high pulmonary arterial pressures. These high pressures make it difficult for the heart to pump blood through the lungs to be oxygenated. Patients with PAH typically develop significant increases in pulmonary vascular resistance (PVR) and sustained elevations in pulmonary artery pressure (PAP), which ultimately lead to right ventricular failure and death.

PAH includes patients with idiopathic PAH, familial PAH, and associated PAH, which is related to certain conditions including connective tissue diseases, congenital systemic-to-pulmonary-shunts, portal hypertension, HIV infection, drugs and toxins. The current treatments for PAH involve calcium channel antagonists, prostacyclins, prostacyclin receptor (IP receptor) agonist, endothelin receptor antagonists, phosphodiesterase-5 (PDE5) inhibitors, and long-term anticoagulant therapy and aim to reduce symptoms, improve quality-of-life and slow disease progression.