Protalix, Chiesi Preparing to Request Accelerated FDA Approval of PRX-102 for Fabry Disease

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by Alice Melao |

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Protalix BioTherapeutics and Chiesi Farmaceutici are planning to submit a biologics license application with the U.S. Food and Drug Administration (FDA) for PRX-102 (pegunigalsidase alfa) as a treatment for Fabry disease, the companies have announced.

After several months, and a series of meetings and correspondence with the FDA, the companies have received a positive opinion from the regulatory agency about the possibility of accelerated approval of PRX-102 to treat people with Fabry disease.

As result, the companies have started to prepare their application — which is expected to be submitted in the first quarter of 2020 — based on available data from Phase 1/2 clinical trials of PRX-102 and from the ongoing Phase 3 BRIDGE study (NCT03018730).

“We are very excited to be one step closer to an approved product to help a patient population that desperately needs a better option than those currently available on the market,” Moshe Manor, president and CEO of Protalix, said in a press release.

“This regulatory approval path is a significant achievement as it means that we can start the application process and potentially attain market approval significantly earlier than the initial plan of data from our ongoing Phase 3 BALANCE clinical trial,” he added.

PRX-102 is an investigational enzyme replacement therapy (ERT) that is being developed to compensate for the lack of alpha-galactosidase A (αGAL-A) enzyme in Fabry patients. This new ERT was developed from Protalix’s plant-based ProCellEx platform that uses plant cells to produce therapeutic proteins, rather than the commonly used mammalian cells which can pose safety issues.

Previous data from Phase 1/2 studies showed that PRX-102 was considered safe, and able to prevent a decline in kidney and heart dysfunction in Fabry patients.

PRX-102 is currently being studied globally in three Phase 3 clinical trials: the BRIDGE, BALANCE (NCT02795676), and BRIGHT (NCT03180840) studies.

Preliminary results from the BALANCE study have demonstrated that PRX-102 is superior to currently available therapy Fabrazyme (agalsidase beta, developed by Sanofi Genzyme) in stabilizing kidney function, and is less suppressed by pre-existing neutralizing antibodies.

Also, data from the BRIGHT study has so far shown that PRX-102 is able to achieve about a sevenfold increase in blood concentrations within 28 days after administration compared with Fabrazyme.

The BRIGHT study — which recently completed enrollment — was designed to evaluate the safety, efficacy, and overall stability and distribution in the body of PRX-102 administered intravenously every four weeks in Fabry patients previously treated with the ERT Fabrazyme or Replagal (agalsidase alpha, marketed by Shire).

“We plan to continue the BALANCE study to further strengthen the profile of pegunigalsidase alfa,” Manor said. “Approval will depend on the formal FDA review, but based on communications with the agency, Protalix remains optimistic that the FDA will approve pegunigalsidase alfa on the accelerated basis.”

In July 2018, Chiesi acquired the exclusive rights to develop and sell PRX-102 in the U.S.

The FDA has granted fast track designation to PRX-102, which is expected to expedite its clinical development and approval as a treatment for Fabry disease.