Rare Daily Staff

Alexion Pharmaceuticals will pay Stealth BioTherapeutics $30 million for an option to co-develop and commercialize Stealth’s late-stage experimental therapy elamipretide for mitochondrial diseases.

Elamipretide is currently being evaluated in a phase 3 study in people with primary mitochondrial myopathy (PMM), a genetic mitochondrial disease. PMM is characterized by debilitating skeletal muscle weakness, chronic fatigue, and exercise intolerance. Under the terms of the agreement, Alexion will have the opportunity to exercise the option following the delivery of results from the phase 3 study currently underway in PMM. There are currently no therapies approved to treat the condition.

Elamipretide is a novel, potential first-in-class therapy that targets mitochondrial dysfunction. It is in clinical development for a variety of diseases caused by mitochondrial dysfunction. Elamipretide targets the inner mitochondrial membrane where it associates with cardiolipin—the signature phospholipid of the inner mitochondrial membrane, which plays a role in many mitochondrial processes, including respiration and energy conversion. Elamipretide has been shown to normalize the structure of the inner mitochondrial membrane, thereby improving mitochondrial function. In preclinical and clinical studies, elamipretide was shown to increase mitochondrial respiration, improve the electron transport chain function and ATP production, and reduce formation of pathogenic reactive oxygen species levels.

Elamipretide is being investigated in late-stage clinical studies in PMM and Barth syndrome, as well as in earlier stage clinical studies in Leber’s hereditary optic neuropathy (LHON) and geographic atrophy associated with dry age-related macular degeneration (GA). Elamipretide has received Fast Track and Orphan Drug designations for PMM, Barth syndrome, and LHON, as well as Fast Track designation for GA.

 “Mitochondria play a critical role in normal organ function and, when dysfunctional, can have devastating consequences on multiple organ systems, leading to many serious diseases, such as primary mitochondrial myopathy,” said John Orloff, executive vice president and head of research and development at Alexion. “Given our strong existing relationships with neuromuscular specialists—who play a critical role in treating PMM—we believe this is an exciting potential opportunity to further expand our rare neurology portfolio and look forward to the possibility of working with Stealth to realize the promise of elamipretide for patients.”

Under the terms of the agreement, Alexion will receive an exclusive option to partner with Stealth in the development of subcutaneous elamipretide based on results from the phase 3 trial. If Alexion chooses to exercise the option, the companies will co-develop subcutaneous elamipretide in the United States for PMM and Barth syndrome, as well as Leber’s hereditary optic neuropathy (LHON), which is currently in earlier stage clinical development.

Upon commercialization, the agreement would provide for a 50-50 co-promote between the two companies in the U.S. and Alexion would receive exclusive rights to develop and commercialize subcutaneous elamipretide outside the United States. Alexion will make initial payments to Stealth totaling $30 million, including an option fee, an equity investment and development funding. If the option is exercised, the agreement provides for additional payments, including an option exercise fee, an additional equity investment, development funding, and potential regulatory and commercial milestone payments. Stealth’s other pipeline assets, including SBT-272, are not included in the option.

Photo: John Orloff, executive vice president and head of research and development at Alexion

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