Gene Therapy Makers Struggle to Find Patients for Miracle Cures

BioMarin Pharmaceutical Inc.’s new treatment for an inherited bleeding disorder was supposed to be a triumph. Aimed at a larger group of patients than the biotech company usually targets, Roctavian was its first foray into gene therapy, a promising field of medicine that fixes genetic flaws to potentially cure diseases.

So far, Roctavian has failed to gain traction in treatment of hemophilia A—just one paying patient in the US was treated with the therapy from the time it won approval last June through the end of 2023, Chief Executive Officer Alexander Hardy said in January at the JPMorgan Healthcare ...