Two days after the U.S. FDA announced approval of gene therapy Lenmeldy (atidarsagene autotemcel), making it the first treatment option for rare disease metachromatic leukodystrophy, Orchard Therapeutics and parent firm Kyowa Kirin Co. Ltd. disclosed the wholesale acquisition price of $4.25 million for the one-time treatment, which edges out hemophilia B gene therapy Hemgenix (etranacogene dezaparvovec) to become the world’s most expensive drug.