Protalix BioTherapeutics and Chiesi Farmaceutici have endured a rejection from the FDA and conducted multiple readouts of a phase 3 trial of their Fabry disease candidate.
After many stops and starts, the companies have finally scored a marketing approval in Europe for PRX-102 (pegunigalsidase alfa), an enzyme replacement therapy for the rare, genetic, progressive disorder, which causes an accumulation of fatty deposits in the lysosomes and strikes roughly 1 in 50,000 people.
The authorization is based on results from a clinical program that has tested PRX-102 in more than 140 patients with up to 7.5 years of treatment.
A head-to-head trial pitting PRX-102 against Sanofi’s Fabrazyme (agalsidase beta) demonstrated noninferior efficacy in controlling the kidney disease that accompanies the disorder.
Fabrazyme, which was approved 20 years ago, is the longtime dominant drug in the Fabry disease market, generating sales of 938 million euros ($986 million) last year.
Amicus Therapeutics of Philadelphia, which earned an FDA approval for its Fabry disease drug Galafold in 2018, reported sales of $329 million last year for the treatment, which has the advantage of coming in tablet form as opposed to Fabrazyme, which—like PRX-102—is administered through IV.
Both Fabry disease treatments cost more than $300,000 annually.
Chiesi and Protalix are still awaiting a nod in the U.S. after getting a fast-track designation in 2018 and submitting for approval two years later. Inspection delays—brought on by the pandemic—helped lead to the FDA rebuff in April of 2021. The companies resubmitted 14 months ago, with an FDA decision expected next week on May 9.
With an approval in the U.S., Protalix of Israel would receive a milestone payment from Chiesi of Italy, which is commercializing the treatment worldwide.