What happened
Shares of BioMarin Pharma (NASDAQ: BMRN) are down 35% at 1:41 a.m. EDT because the U.S. Food and Drug Administration has issued a full response letter for the biotech hemophilia A gene therapy, valoctocogenic roxaparvovec (valrox).
So what
A full response letter is the FDA’s euphemism for a rejection letter. The review is complete, but the agency needs more information before it can approve the treatment.
In BioMarin’s case, it appears that the FDA moved the target post for approval.
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The agency had previously told BioMarin that it could submit the marketing application with interim data from the Phase 3 clinical trial that increased the activity of Factor VIII activity, the coagulation factor missing in patients with hemophilia A. Valrox states the Factor VIII gene in patients’ cells, allowing their blood to die after they are cut.
The FDA also wanted to see long-term data provided by BioMarin from patients enrolled in the Phase 1/2 clinical trial since they were treated four years ago. Unfortunately, the FDA concluded that there were differences between the Phase 1/2 study and the Phase 3 study, which made it difficult for the agency to mesh the long-term data from the Phase 1 / 2-study and the larger-but-shorter phase 3-study.
Well what
Now the FDA wants to show two-year data from the Phase 3 study that valrox lowers the annual blood rate, which will not be ready until November 2021. The biotech will then have to process the data and resubmit the marketing application, pushing for a potential approval in 2022
The delay is a big blow for BioMarin, which relied on valrox to push it forward. BioMarin sells multiple drugs for rare diseases, but valrox is its first legitimate opportunity to have a blockbuster treatment with more than $ 1 billion in sales.
Waiting two years for an approval also gives Pfizer en Sangamo Therapeutics an opportunity to pick up their Factor VIII gene therapy candidate, giroctocogenic fitelparvovec, which plans to enter a Phase 3 clinical trial shortly.
