PTC Therapeutics has announced the selection of a development candidate in its spinal muscular atrophy (SMA) collaboration with Roche and the SMA Foundation. The achievement of the milestone triggers a $10 million payment to PTC from Roche.

SMA is caused by a missing or defective SMN1 gene, which results in reduced levels of the survival motor neuron (SMN) protein. It is a genetic neuromuscular disease responsible for the early death of motor neuron cells within the spinal cord leading to muscle atrophy and eventually death, in the most severe form of the disease. The oral small molecule compounds in the program target the underlying cause of the disorder by increasing SMN protein levels in the nervous system, muscles and other tissues. It is estimated SMA affects approximately 10,000 to 25,000 children and adults in the U.S., and between one in 6,000 and one in 10,000 children are born with this rare disorder.

The SMA program initially was developed by PTC Therapeutics' in partnership with the SMA Foundation. The SMA Foundation was established in 2003 to accelerate the development of a treatment. In November 2011, Roche gained an exclusive worldwide license to PTC's SMA program. PTC received a $30 million upfront payment and may receive up to an additional $450 million upon successful completion of other development and commercialization milestones, plus tiered royalties on worldwide net product sales. Development is overseen by a joint steering committee comprised of members from Roche, PTC and the SMA Foundation.