Questions about whether it would work for a lifetime or just a few years came amid rumors that Biomarin might set a price tag as high as $3 million per patient. That would top the price for the most expensive therapy ever approved by the FDA, Swiss drugmaker Novartis AG's gene therapy for spinal muscular atrophy, Zolgensma, which was launched in spring 2019 with a $2.125 million price tag per patient.