BioMarin Pharmaceutical is set to begin a Phase 1/2 clinical trial to test BMN 307, its investigational gene therapy for phenylketonuria (PKU), in the first quarter of 2020.
The company recently announced the approval of its clinical trial application submitted in late 2019 to the United Kingdom’s Medicines and Healthcare products Regulatory Agency.
Moreover, BMN 307 has also been granted Investigational New Drug status by the United States Food and Drug Administration (FDA).
PKU is caused by mutations in the PAH gene which lead to a decrease in the levels of phenylalanine hydroxylase (PAH), an enzyme responsible for breaking down phenylalanine (Phe). Phenylalanine is an essential amino acid frequently found in many protein-containing foods, so patients with PKU have to maintain lifelong restrictive diets.
If left untreated, accumulation of Phe becomes toxic to the brain and can lead to severe neurological issues.
To date, BioMarin’s Kuvan (sapropterin dihydrochloride) and Palynziq (pegvaliase-pqpz) are the only approved treatments for PKU.
BMN 307 is a gene therapy candidate that aims to treat the cause of the disease, by delivering a functional PAH gene to the cells, leading to the production of PAH and normalization of Phe levels. It has been granted orphan drug designation by the FDA and the European Medicines Agency.
Preclinical results have shown that administration of BMN 307 to a mouse model of PKU led to a normalization of Phe levels.
In the new trials, BMN 307 will be evaluated to determine whether a single dose can help restore natural Phe metabolism, normalize Phe levels, and allow patients with PKU to eat a normal diet.
Biomarin is expected to start dosing patients in the Phase 1/2 study, known as PHEARLESS, in the first quarter of 2020. BMN 307 will be produced on a commercial scale from the company’s award-winning gene therapy manufacturing facility.
The PHEARLESS study will consist of a dose-escalation phase, which will be followed by a cohort expansion phase once the ideal dose has been selected.
At this time, BioMarin is actively formulating regulatory submissions that will allow it to open extra clinical sites in other countries.
“With BMN 307, we are joining together our expertise in PKU biology and the knowledge we have gained from developing the only two approved therapies for PKU with our understanding of gene therapy clinical development and manufacturing from our valoctocogene roxaparvovec experience,” Hank Fuchs, MD, president of worldwide research and development at BioMarin, said in a press release.
“BioMarin has stood with the PKU community for over 15 years and remains dedicated to continuing to increase the body of medical knowledge in this devastating disease,” he added.
BioMarin is also sponsoring an observational study (NCT03505125) known as PHENOM to measure both known and novel markers of disease and PKU patients’ clinical outcomes over time, for future clinical trials. The study has been recently completed.