Experimental PH Treatment, Ubenimex, Recognized as Orphan Drug by EMA in Advance of Clinical Study

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by Patricia Silva PhD |

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ubenimex, a potential PH therapy

Eiger BioPharmaceuticals recently announced that its protease inhibitor ubenimex has been granted Orphan Medicinal Product designation by the European Medicines Agency (EMA) for the treatment of pulmonary arterial hypertension (PAH). The company will soon begin a Phase 2 clinical trial testing ubenimex in this patient group.

The EMA designation covers products meant for the diagnoses, prevention, or treatments of life-threatening or severe but rare conditions, affecting up to 5 in every 10,000 people in the European Union (EU). Orphan medicinal product status makes the promoter of the drug candidate eligible for a series of development incentives, including the possibility of fee waivers for regulatory procedures, or a 10-year market exclusivity period after approval of the drug candidate.

Ubenimex is a well-characterized, oral small molecule, dual-inhibitor of aminopeptidase and leukotriene A4 hydrolase (LTA4H) — the enzyme that is responsible for triggering the formation of the pro-inflammatory mediator, LTB4. It is approved in Japan as an addition to chemotherapy agents to extend post-treatment survival and remission in adults with acute non-lymphocytic leukemia, and has been commercially available there under the name Bestatin. Ubenimex has not been approved for any indications in the U.S. or EU, but it also received orphan drug designation from the U.S. Food and Drug Administration (FDA) as a potential PAH treatment in November 2015.

“We are very pleased with the EMA Committee of Orphan Medicinal Products (COMP) designation of orphan status for ubenimex in PAH,” Joanne Quan, Eiger’s chief medical officer, said in a press release. “We will soon begin enrolling the LIBERTY study, a Phase 2, randomized, double-blind, placebo-controlled, multi-center study of ubenimex in PAH patients.”

PAH is a progressive, life-threatening disease marked by elevated blood pressure that affects the arteries in the lungs and the right side of the heart. PAH develops when arterioles, or small lung arteries, are constrained, blocked, or destroyed. This can compromise the blood flow through the lungs, and raise the pressure within the arteries of the lungs. As the pressure increases, the heart’s lower right chamber, or right ventricle, has to pump harder to pass blood through the lungs, which eventually leads to heart muscle weakening and, eventually, heart failure.