Alexion and Stealth BioTherapeutics agree option for Alexion to participate in elamipretide for mitochondrial diseases.

Alexion Pharmaceuticals, Inc.and Stealth BioTherapeutics Corp announced an agreement for an option to co-develop and commercialize elamipretide for mitochondrial diseases. Currently being evaluated in a Phase III study in people with primary mitochondrial myopathy (PMM) - a genetic mitochondrial disease - elamipretide is a novel, potential first-in-class therapy that targets mitochondrial dysfunction. There are currently no therapies approved to treat PMM, which 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 III study currently underway in PMM. Under the terms of the agreement, Alexion will receive an exclusive option to partner with Stealth in the development of subcutaneous elamipretide based on final results from the Phase III study currently underway in PMM. If Alexion chooses to exercise the option, the companies will co-develop subcutaneous elamipretide in the U.S. 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 U.S. 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.