A treatment for Fabry disease, a rare X-linked genetic disease that causes progressive buildup of a fatty substance called globotriaosylceramide around the body, has achieved good results at Phase III, report developers Protalix BioTherapeutics and Chiesi Global Rare Diseases.
Fabry disease occurs in one person per 40,000-60,000 people and is caused by a genetic variant on the X-chromosome that causes the lysosomal α Galactosidase A enzyme to malfunction. The fatty deposits that build up gradually around the body cause a range of symptoms from pain to peripheral nerve damage and inevitably leads to kidney, heart and other organ failure.
There are already a couple of enzyme replacement therapies on the market for treatment of the condition, but only Fabrazyme, developed and manufactured by Sanofi-Genzyme, is approved in the U.S. and can be hard to access and expensive.
Protalix and Chiesi’s treatment, currently known as PRX-102, is also a form of enzyme replacement produced in specially engineered plants developed by Protalix. The Phase III trial included 30 adults with Fabry disease (24 men, 6 women) between the age of 19 and 58 years. All the participants had previously been treated with one of the two approved therapies and so were in good health at the start of the study.
The trial was an open-label, switch-over study carried out across different countries and medical centers and was designed to assess the safety and efficacy of treatment with 2 mg/kg of PRX-102 administered every four weeks for 52 weeks.
The trial met its endpoints and no notable increases in globotriaosylceramide were seen in the participants. Kidney health, as measured by eGFR, was also stable.
Only one participant withdrew, for non-trial related reasons. Side effects from the therapy were mild to moderate, mostly infusion site reactions, and only occurred in 30% of participants.
“We are excited to share the final data from the BRIGHT study, an important milestone in the progress of our PRX-102 clinical program,” said Dror Bashan, Protalix’s President and CEO. “The availability of this data for review by the U.S. Food and Drug Administration, the European Medicines Agency and other regulators is another step forward towards the anticipated approval of PRX-102 as a potential good alternative for adult Fabry patients in both the regular 1 mg\kg every two weeks as well as the 2 mg\kg every four weeks regimen.”
Data has already been submitted to both regulatory agencies in anticipation of market approval, but the companies will continue to follow-up the trial participants for potential side effects in a longer-term follow-up extension study.
Protalix achieved its first FDA approval of a protein developed through its plant-based protein expression system in 2012, taliglucerase alpha for long-term enzyme replacement therapy for patients with type 1 Gaucher disease.
