Scholar Rock says its first muscle-targeted SMA therapy will cost about $310,000 annually

The therapy, branded as Isembyld, won approval for use in all adults and children over 2 years of age with spinal muscular atrophy who are currently receiving therapies that target SMN2, a gene for neurons that control movement.

"In terms of the launch, we expect a steady and consistent pace of Isembyld patient starts as we work to serve a gradually increasing number of children and adults living with SMA," Chief Operating Officer Keith Woods said.

Sept. 14 (Reuters) - Scholar Rock SRRK.O on Monday said the net annual cost of its newly approved spinal muscular atrophy treatment will be about $310,000 for a typical patient, after the drug became the first therapy approved to directly target muscle loss associated with the rare genetic disorder.

The cost will depend on a patient's weight and insurance coverage, the company's executives said, with a typical patient in the 35 kg to 45 kg range expected to receive approximately three vials every four weeks.

The wholesale acquisition cost for a single-use vial is $11,659. The company has commenced the launch of Isembyld immediately upon Friday's approval.

Scholar Rock's shares were about 5% higher before the bell on Monday.

The genetic disease results in irreversible loss of motor neurons and progressive muscle wasting, leading to motor function decline.

In a late-stage trial, the drug, when combined with an SMN2-targeting drug, helped patients' motor skills to significantly improve compared to placebo.

Isembyld selectively blocks activation of myostatin, a protein that limits muscle growth, with the aim of increasing muscle mass and strength.