Protalix BioTherapeutics Reports Positive Topline Results for Fabry ERT

Rare Daily Staff

Protalix BioTherapeutics reported positive topline results from its phase 3 BRIDGE clinical trial of PRX-102, the company’s plant cell-expressed recombinant enzyme replacement therapy for the treatment of the lysosomal storage disorder Fabry disease.

Fabry disease is a rare, genetic disease in which a deficiency of the lysosomal α‑galactosidase‑A enzyme results in progressive accumulation of abnormal deposits of a fatty substance called globotriaosylceramide (Gb3) in blood vessel walls throughout a person’s body. The abnormal storage of Gb3 increases with the ultimate consequences of Gb3 deposition ranging from episodes of pain and impaired peripheral sensation to end-organ failure – particularly of the kidneys, but also of the heart and the cerebrovascular system.

Pegunigalsidase alfa (PRX‑102) is an experimental, plant cell culture-expressed, and chemically modified stabilized version of the recombinant α-galactosidase-A enzyme. In clinical studies, PRX‑102 has been observed to have a circulatory half-life of approximately 80 hours. The company designed PRX‑102 to potentially address the continued unmet clinical need in Fabry patients.

The BRIDGE study was a phase 3, 12 month open-label, single arm switch-over study evaluating the safety and efficacy of pegunigalsidase alfa, 1 mg/kg infused every two weeks, in up to 22 Fabry patients previously treated with agalsidase alfa, marketed by Takeda Pharmaceutical as Replagal, for at least two years and on a stable dose for at least six months.

Topline results of the data generated in the study showed substantial improvement in renal function as measured by mean annualized estimated Glomerular Filtration Rate (eGFR slope) in both male and female patients who were switched from agalsidase alfa to PRX-102.

Consistent with previously announced interim data, PRX-102 was found to be well tolerated, with all adverse events being transient in nature without sequelae. Twenty-two patients were enrolled in the study; two of those patients withdrew early from the study due to hypersensitivity reaction, and 20 of the patients successfully completed the 12-month treatment duration. Eighteen of the patients who completed the study opted to roll over to a long-term extension study and continue to be treated with PRX-102.

“The completion of our phase 3 BRIDGE study and its subsequent analysis mark a significant milestone towards our goal to establish PRX-102 as a new treatment option for Fabry disease,” said Dror Bashan, Protalix’s President and CEO. “As the first of our three studies to complete phase 3, we believe the BRIDGE study findings support that PRX-102 has the potential to be an important enzyme replacement therapy for the treatment of Fabry disease.”

Photo: Dror Bashan, Protalix’s President and CEO