The U.S. Food and Drug Administration has approved Johnson & Johnson's drug to treat some patients aged 12 years and older with an immune-mediated disorder, the drugmaker said on Wednesday.

The drug, which will be sold under the brand name Imaavy, was approved for patients with generalized myasthenia gravis - an immunity-related disorder that weakens the skeletal muscles, especially those in the eyes, mouth, throat and limbs.

The disorder affects about 10 to 20 individuals per 100,000 in the United States, according to government data.

J&J acquired the drug with its $6.5 billion buyout of autoimmune disease specialist Momenta in 2020.