US FDA approves J&J's immune disorder drug

By Christy Santhosh

April 30 (Reuters) - The U.S. Food and Drug Administration on Wednesday approved Johnson & Johnson's JNJ.N drug to treat a type of muscle-weakening disorder, which is expected to bring in blockbuster revenues and drive growth.

J&J had acquired the drug, to be sold under the brand name Imaavy, through its $6.5 billion buyout of Momenta in 2020.

Imaavy was approved to treat patients aged 12 years and older with a form of generalized myasthenia gravis (gMG) — an immunity-related disorder that weakens the skeletal muscles, especially those in the eyes, mouth, throat and limbs.

The drug will compete with other approved treatments for the condition, such as those by Argenx SE ARGX.BR, AstraZeneca AZN.L and UCB UCB.BR.

J&J expects the drug to bring in over $5 billion in peak sales and is also testing it for other immune disorders, including Sjögren's disease and chronic inflammatory demyelinating polyneuropathy. Leerink analysts estimate Imaavy to generate $2.3 billion in sales by 2032.

J&J's global immunology head, David Lee, said the drug aims to address autoantibodies which are one of the root causes of the disease.

"There is more than one kind of antibody that can interrupt that interaction between the muscle and the nerve," he said, adding that Imaavy addresses two of those antibodies.

While there are several types of gMG, the drug approval covers more than 90% of the patient population, J&J said.

The disorder affects about 100,000 people in the U.S., according to company estimates.

J&J has set a list price of $12,480 for a 1200 milligram (mg) vial, although patients will pay based on their insurance plan.

The approval was based on a 24-week late-stage study where Imaavy helped improve how patients performed essential daily functions such as chewing, speaking and breathing.