- BioMarin's daily injectable drug for the rare, genetic disease phenylketonuria (PKU) hit its primary endpoint but failed to meet important secondary goals, the company said on Monday. The drug, pegvaliase, significantly lowered phenylalanine (Phe) levels by 62%. However, it failed to generate improvement in patients' attentiveness or mood.
- Patients with PKU lack the enzyme that breaks down Phe. As a result, the body becomes overloaded, leading to intellectual disability and other neurological problems if not properly treated.
- BioMarin intends to file by the end of the year, but is seeking guidance from the FDA as it prepares its submission.
BioMarin also makes the only currently approved treatment for PKU. That treatment, Kuvan, is an oral therapy intended to be used with a protein-restricted diet. When patients follow the Kuvan-based regimen, Phe levels decline by 40% to 50%. Yet there is a medical need for another therapy.
With pegvaliase, the aim is to lower Phe but without also requiring a restricted diet and proten intake. Despite hitting the primary endpoint in the study, the phase 3 results were not encouraging in terms of the effect on attentiveness and mood.
However, longer term follow-up through 41 weeks did show improvements in attentiveness and mood and may be the key to getting a positive response from regulatory authorities. A positive response from the FDA would brighten up what has been a tough several months for BioMarin, after the FDA rejected its drug Kyndrisa for treatment of Duchenne's muscular dystrophy in January.
On the bright side, Kyndrisa is still under review in the E.U. and could win approval in that market, as BioMarin waits on pegvaliase in the U.S. market.