The Food and Drug Administration may need an additional three months to review BioMarin Pharmaceutical’s experimental gene therapy for severe hemophilia, potentially adding another delay in the biotechnology company’s long road to a decision on the treatment’s approval.
The regulator wants to look over three-year follow-up results from BioMarin’s principal clinical trial, the company said Monday evening. The additional data might constitute what the FDA terms a “major amendment” to the drug’s application and necessitate a review extension.
Currently, the FDA is due to make a decision on approval of the treatment, called Roctavian, by March 31. It will review the additional three-year data prior to making a determination on whether it needs an additional three months, BioMarin said.
“We are not surprised that the FDA wants to make especially sure that they do not make such a momentous decision in a hasty manner,” Joseph Schwartz, an analyst at SVB Securities, wrote in a Monday note to clients.
BioMarin first sought approval for Roctavian in late 2019, but the next year had its application unexpectedly rejected by the FDA, which requested additional study data to assess how the therapy’s benefit held up over time. BioMarin subsequently collected those results and used them to support the application that’s now under review.
By early 2023, however, full three-year data from the company’s main trial of Roctavian will be available and could inform the FDA’s thinking.
“FDA stated that these data are expected to provide longer-term efficacy and safety information and would thus be useful to people with Hemophilia A and healthcare providers in making better and more informed decisions when considering valoctocogene roxaparvovec as a treatment choice should it be approved," Hank Fuchs, BioMarin’s head of R&D, said in the company’s Monday statement. (Valoctocogene roxaparvovec is the scientific name for Roctavian.)
Notably, the results might also inform a planned discussion by FDA advisers of BioMarin’s application. That meeting is not currently scheduled, but will be an important venue for the biotech to make a case for its therapy.
Between now and then, the FDA will also inspect the BioMarin facility where the company intends to manufacture commercial supplies of Roctavian. BioMarin said Monday the inspection had been scheduled, but did not give a date.
Roctavian is designed to deliver a functional copy of the gene that’s faulty in people with severe hemophilia A, a blood disease that impairs the body’s ability to clot blood. Study results have shown that treatment can restore levels of the needed clotting protein to slightly lowered or even near-normal levels, allowing trial participants to discontinue routine preventive drugs.
The durability of the treatment’s benefit has come in question, however, as follow-up data have shown clotting protein levels can wane over time. Hemophilia patients also have a number of treatments currently available to them, potentially informing the FDA’s consideration of Roctavian’s benefit-risk profile.
However, many analysts expect the FDA’s ultimate decision will be favorable. “We continue to believe that it is a matter of when not if Roctavian gets approved in the US and believe we are nearing the finish line,” Schwartz wrote.