New FDA-approved gene therapy for kids will cost record $4.25 million

A new one-time gene therapy that treats a rare disease in children will cost an eye-popping $4.25 million, making it the world’s most expensive drug.

The Food and Drug Administration approved Lenmeldy, the first drug able to treat metachromatic leukodystrophy, on Monday. The gene therapy will treat the condition in infants and children both before and after symptoms develop. 

Metachromatic leukodystrophy, which affects one in 40,000 Americans, involves an enzyme deficiency that leads to the buildup of fatty substances in cells, which in turn harms the nervous system, particularly a person’s ability to move and think. The FDA says the disease, which can lead to an early death, has no known cure.

The maker of Lenmeldy, Orchard Therapeutics, says the disease affects one in 100,000 live births, less than 40 U.S. babies annually. 

“Lenmeldy … has the potential to stop or slow the progression of this devastating childhood disease … We are committed to enabling broad, expedient and sustainable access to this important therapy,” Orchard Therapeutics CEO Dr. Bobby Gaspar said in a statement.

The $4.25 million wholesale price tag for the drug “is reflective of the value the therapy may deliver to eligible patients and their families, as well the potential long-term impact treatment may have on overall healthcare utilization, minimization of productivity loss for caregivers, and life opportunities for patients,” Orchard Therapeutics said.

The nonprofit Institute for Clinical and Economic Review said in October 2023 that a price between $2.3 million and $3.9 million would be cost-effective for patients.

“I think when you get into numbers this big that people don’t necessarily pay attention when it gets a little bigger, but I do think this price is too high. … Going $310,000 above the very top of that range is actually a lot of money,” institute Chief Medical Officer Dr. David Rind told CNN.

The second-most expensive drug, a treatment for blood clotting disorder hemophilia B released in 2022, costs $3.5 million.

Lenmeldy involves combining a patient’s blood cells with a functioning gene that produces the correct enzymes and then injecting the new cells into the patient. Chemotherapy is required before treatment to remove cells that are replaced, the FDA said. The new cells produce the enzyme that breaks down the fatty substances, helping to stop the progression of the disease.

In clinical studies, 71% of children treated with Lenmeldy for pre-symptomatic late infantile metachromatic leukodystrophy were able to walk without assistance and 85% had normal language and IQ scores at age 5.