Protalix eyes Fabry drug resubmission thanks to multiple phase 3 readouts

Protalix BioTherapeutics intends to resubmit its once-rejected Fabry disease drug to the FDA in the second half of this year thanks to new phase 3 data, with more on the way in the coming weeks, a company spokesperson told Fierce Biotech.

The biotech already asked the European Medicines Agency to greenlight the drug, dubbed pegunigalsidase alfa (PRX–102), last month. Now, it plans to ship PRX-102 off to the FDA for a second time after the agency rejected the drug in April 2021. Timing of the resubmission was unclear when the Israeli biotech reached an agreement with the FDA in October 2021 on a data package for the second try. PRX–102 is being developed in a partnership with Chiesi Farmaceutici S.p.A., which has exclusive rights to commercialize the drug worldwide. 

Protalix's shares climbed 15% on the news to $1.07 apiece as 10:01 a.m. ET on Friday. 

Fabry is a rare disease caused by a mutation of the GLA gene, which means the body has a tougher time producing a certain enzyme that is meant to break down lipids. The absence of the enzyme causes lipid to accumulate and impact blood vessels. The disease is part of the family of lysosomal storage disorders.

CEO and President Dror Bashan said Protalix the data is "another step forward" in the direction of getting an anticipated approval with results from one of three phase 3 studies Friday. The IV-delivered drug, when given at 2mg/kg every four weeks, met safety, efficacy and pharmacokinetics goals in the late-stage Bright trial, the biotech said Friday. 

The study enrolled 30 patients, including 24 men and six women who ranged in age from 19 to 58 years old. The patients had previously received an enzyme replacement therapy for at least three years, including Sanofi's Fabrazyme or Replagal. One patient withdrew due to a traffic accident, the company said.

All but one of the 29 patients to complete the study received the intended regimen of 14 infusions across 52 weeks. One patient switched to a lower dose at the 11th infusion. The drug did not lead to serious or severe adverse events, Protalix said. 

Now, the company awaits topline data from a separate phase 3 trial, named Balance, which is slated for the coming weeks or months, a spokesperson told Fierce Biotech in an emailed statement. The 24-month study is comparing PRX-102 to Fabrazyme, which received accelerated approval from the FDA nearly 19 years ago.