European Commission Approves Dosing Regimen for Fabry Disease Treatment

Chiesi Global Rare Diseases and biopharma company, Protalix BioTherapeutics, announced on March 9, 2026 that the European Commission (EC) has approved a 2mg/kg every-4-weeks dosing regimen for Elfabrio (pegunigalsidase alfa) in adults with Fabry disease who are stable with an enzyme replacement therapy (ERT).1 Elfabrio was approved by the European Medicines Agency’s (EMA) Committee for Medicinal Products for Human Use (CHMP) in February 2023.2 The EC approval of the new dosing regimen gives Protalix a regulatory milestone payment of $25 million from Chiesi.

Why does the change in dosage matter?

According to the press release,1 the approved dosing regimen reduces burdens on patients and the health care system by extending infusion intervals. EC based the approval on results from an open-label, switch-over study that assessed the adverse-event profile, efficacy, and pharmacokinetics of the alternative dosing regimen, as well as an ongoing open-label extension study.

“The European Commission approval for 2mg/kg body weight E4W dosing regimen for pegunigalsidase alfa represents a meaningful advancement for adults living with Fabry disease and their families,” said Giacomo Chiesi, executive vice president, Chiesi Global Rare Diseases, in the press release.1 “Because Fabry disease requires lifelong treatment, the cadence of therapy inevitably becomes part of everyday life for patients and caregivers. By introducing an option that extends the infusion interval from every two weeks to every four weeks for eligible patients on stable ERT, we are offering families greater flexibility and the possibility to ease the overall burden of treatment. Ultimately, our goal is simple but profound: to help people spend less time managing their disease and more time living their lives. This milestone reflects our commitment to innovation that goes beyond delivering therapies—by listening to and understanding the real experiences of the Fabry community.”

“In Fabry disease, long-term treatment decisions must balance disease management with the realities of lifelong therapy,” said Prof. Aleš Linhart, DrSc, FESC., in the press release.1 “The approval of pegunigalsidase alfa 2mg/kg every-4-weeks provides an additional option that may help reduce cumulative treatment burden for appropriate patients while maintaining continuity of care.”

“This approval strengthens the treatment landscape for Fabry disease across the European Union by introducing an additional dosing approach that has the potential to enhance long-term care, " said Dror Bashan, president and chief executive officer, Protalix, in the release.1 “The authorization reflects not only scientific progress, but also a commitment to optimizing care delivery in a way that supports both patients and healthcare systems.”

“For many people living with Fabry disease, treatment is a lifelong commitment that impacts nearly every aspect of daily life,” said Mary Pavlou, president, Fabry International Network (FIN), in the release.1 “This approval allows for fewer infusion visits, helping reduce the ongoing burden on patients and families, allowing them to spend more time living their lives beyond treatment.”

How does Elfabrio work?

According to the companies, Elfabrio (pegunigalsidase alfa-iwxj), a PEGylated ERT to treat Fabry disease, “is a plant cell culture-expressed, and chemically modified stabilized recombinant version of the α—Galactosidase—A enzyme. Protein sub-units are covalently bound via chemical cross-linking using short PEG moieties, resulting in a molecule with stable pharmacokinetic parameters. In clinical studies, Elfabrio has been observed to have an initial half-life of 78.9 ± 10.3 hours.”1

The new dosing regimen is for Europe only. In the United States, the FDA-approved dosing regimen of 1-mg/kg every 2 weeks remains.

What happened to the previous requests for a 4-week dosing regimen?

In October 2025, the CHMP gave a negative opinion on a dosing regimen of 2 mg/kg body weight infused every 4 weeks for Elfabrio.3 The committee found that trial data were not sufficient to determine similar efficacy. However, in January 2026, CHMP provided a positive opinion on the dosing change after re-examining the application.4

“The CHMP’s positive opinion is another testament to Protalix’ s commitment to advancing treatments for people living with Fabry disease and, together with Chiesi, we are grateful to all of the patients and investigators and their staff members who participated in our clinical trial programs," said Bashan in the press release.4 “The CHMP’s positive opinion is a powerful validation for Protalix’ s innovative pipeline and our proprietary ProCellEx manufacturing platform, built on years of rigorous research and clinical progress.”

An open-label, switch-over trial, BRIGHT (formally PB-102-F50), and an ongoing open label extension study, CLI-06657AA1-03 (formerly PB-102-F51), have a median exposure of almost 6 years. These studies evaluated pegunigalsidase alfa 2 mg/kg administered every 4 weeks with additional support from modeling and exposure-response analyses across prior trials (PB-102-F01/-F02, PB-102-F20, and PB-102-F50).

References

1. Chiesi Global Rare Diseases and Protalix BioTherapeutics announce European Commission approval of additional dosing regimen of every four 2eeks for Elfabrio® (pegunigalsidase alfa). Press release. Chiesi Global Rare Diseases. March 9, 2026. https://chiesirarediseases.com/media/20260309-chiesi-global-rare-diseases-and-protalix-biotherapeutics-announce-european-commission-approval-of-additional-dosing-reg
2. Meeting highlights from the Committee for Medicinal Products for Human Use (CHMP) 20–23 February 2023. Press release. European Medicines Agency. February 24, 2023. https://www.ema.europa.eu/en/news/meeting-highlights-committee-medicinal-products-human-use-chmp-20-23-february-2023
3. Chiesi Global Rare Diseases and Protalix BioTherapeutics acknowledge CHMP negative opinion on every four week dosing regimen of Elfabrio® (pegunigalsidase alfa) in the EU. Chiesi Global Rare Diseases. October 17, 2025. https://chiesirarediseases.com/media/20251016-chiesi-global-rare-diseases-and-protalix-biotherapeutics-acknowledge-chmp-negative-opinion-on-every-four-week-dosing
4. Chiesi Global Rare Diseases and Protalix BioTherapeutics receive positive CHMP opinion for an additional dosing regimen of every four weeks for Elfabrio® (pegunigalsidase alfa) in the EU. Press release. Protalix BioTherapeutics. January 30, 2026.https://ir.protalix.com/news-releases/news-release-details/chiesi-global-rare-diseases-and-protalix-biotherapeutics-4