FDA Reviewing Application of PRX-102 as Fabry Treatment

Note: This story was updated Sept. 9, 2020, to reflect that PRX-102 is licensed to Chiesi for all markets, including the U.S.

The U.S. Food and Drug Administration (FDA) has accepted for review an application from Chiesi Global Rare Diseases and Protalix BioTherapeutics that asks for approval of PRX-102 (pegunigalsidase alfa) as a treatment for adults with Fabry disease.

The biologics license application (BLA) was submitted in May through the FDA’s accelerated approval pathway program, and it has been given priority review. That designation is granted to therapies that have the potential to markedly improve care for serious conditions, which shortens the FDA review period to six months, from the usual 10.

A decision on the BLA is expected no later than Jan. 27, 2021.

“The FDA’s acceptance of the BLA and grant of priority review for PRX-102 are significant achievements for Protalix and Chiesi, and represent a crucial step forward as we look to establish a new treatment option to the Fabry patient community,” Dror Bashan, president and CEO of Protalix, said in a press release.

Fabry disease is caused by a lack of functional alpha-galactosidase A, an enzyme responsible for breaking down certain kinds of fat molecules. PRX-102 is a recombinant (lab-made) version of this enzyme that is intended to be administered by injection into the blood stream, compensating for the lack of the naturally-occurring enzyme.

PRX-102 is specifically a version of alpha-galactosidase A made with Protalix’s plant-based ProCellEx platform that has been chemically modified so it will last longer in the body. As such, it may require less frequent infusions than existing enzyme replacement therapies.

The medication was developed by Protalix, which licensed it to Chiesi for all global markets.

The companies’ BLA is supported by data from multiple clinical trials, including an open-label Phase 1/2 clinical trial (NCT01678898) and its extension study (NCT01769001), in which participants were given PRX-102 injections every two weeks. Results indicted that the medication stayed active in participant’s blood, decreased levels of disease biomarkers, improved kidney function, and slowed disease progression.

The BLA also is supported by data from the ongoing Phase 3 clinical trial BRIDGE (NCT03018730), which is testing the safety and effectiveness of PRX-102 in adults with Fabry disease who have been treated previously with Replagal (agalsidase alpha), a widely-approved enzyme replacement therapy for Fabry disease.

Interim findings from BRIDGE suggested that PRX-102 was well -tolerated and effectively slowed the progression of kidney disease.

“Based on the encouraging results for PRX-102 we have seen to date, we are eager to continue discussions with the FDA and to continue our other development efforts for PRX-102, as marketing approval of PRX-102 is our top priority,” Bashan said.

Giacomo Chiesi, head of Global Rare Diseases, added, “PRX-102 represents an important advance in research with the potential to deliver significant advantages to patients with Fabry disease. We are very encouraged by the strong interest in this therapy among both patients and clinicians and we look forward to the prospect of making it available to patients around the world who can benefit from treatment.”