A high-priced drug approved last week to treat a rare disease that affects young boys is not hitting the market after criticism over its $89,000-a-year price tag.

Marathon Pharmaceuticals said Monday that it is delaying the launch of Emflaza, a drug to treat the rare muscular disorder Duchenne muscular dystrophy. The Illinois drugmaker didn’t say how long the drug would be delayed or when it initially planned to hit the market.