BioMarin has gained European Union approval for Palynziq (pegvaliase injection) for the rare metabolic condition phenylketonuria (PKU).
The EU decision comes a year after the FDA approval of the treatment, which is BioMarin’s follow-up to its existing PKU drug, Kuvan.
Palyniq is an advance on the existing treatment, representing the first enzyme substitution therapy approved in Europe to treat the underlying cause of PKU, which is the build up of Phe, an amino acid found in most forms of protein which PKU patients cannot clear because of a genetic defect.
The condition can be managed with a strict Phe-restricted diet, based on low-protein modified foods and Phe-free medical foods. However, it is difficult for most adult patients to adhere to this strict diet, and Palyniq allows patients to increase their protein intake towards more normal levels.
BioMarin has identified Palyniq as having potential to break through the annual $1bn sales mark, but analysts forecast this to be nearer $500m. The main factor informing this lower total is the black box warning of anaphylaxis the treatment carries in the US and now Europe, which means the dosing must be titrated initially, and patients must carry with them an auto-injectable adrenaline pen.
The drug is now licensed in Europe for patients aged 16 years or older at doses up to 60 mg, and trial data shows it lower Phe levels, as well as suggesting beneficial effects on inattention and mood symptoms, which are characteristic of the condition.
The Palynziq approval was based on data from an eight-week phase 3 pivotal study, PRISM-2 and an ongoing open label extension study at 36 months.
This longer term data shows that at 36 months, 66% reached Phe levels of ≤360 µmol/L and 72% reached Phe levels of ≤600 µmol/L, the recommended treatment target in the EU.
Patients were also able to increase their protein intake from intact food of 25g over baseline after 36 months on treatment.
Announcing the firm’s recent Q1 results, Jean-Jacques Bienaimé, chairman and chief executive of BioMarin, said the company was “thrilled with the pace of the US launch” the treatment now reimbursed in 414 US patients.
Most promisingly, the company has a third PKU treatment in its pipeline, this time a therapy which tackles the genetic basis of the disease.
The company anticipates filing an IND for its gene therapy, named BMN 307, in the second half of 2019. The company says BMN 307 has demonstrated lifetime normalisation of Phe in a validated PKU mouse model, results which it hopes to replicate in humans and which would allow it to expand its PKU franchise significantly.
This strategy is in line with BioMarin’s most promising late-stage candidate, valoctocogene roxaparvovec a gene therapy for severe haemophilia A. The company’s pivotal study for the therapy is track to complete enrolment in the third quarter, and could take up an opportunity to use an FDA accelerated approval pathway.