Protalix stock plunges after negative CHMP opinion on dosing regimen

Published 17/10/2025, 13:40
© Reuters.

Investing.com -- Protalix BioTherapeutics Inc (NYSE American:PLX) stock plunged 20.8% in premarket trading Friday after the Committee for Medicinal Products for Human Use (CHMP) of the European Medicines Agency (EMA) issued a negative opinion on the company’s request to approve an alternative dosing regimen for Elfabrio.

The CHMP rejected the proposed dosing regimen of 2 mg/kg body weight infused every 4 weeks (E4W) for Elfabrio (pegunigalsidase alfa), which would have been in addition to the currently approved dosing regimen of 1 mg/kg body weight infused every 2 weeks (E2W).

The submission for CHMP review was based on data from an open-label, switch-over trial called BRIGHT and its ongoing open label extension study. The combined studies have a median exposure of almost six years. Additional support came from modeling and exposure-response analyses across prior trials, but the CHMP determined these data were "not deemed sufficient to conclude on similar efficacy."

Despite the setback, both Protalix and its partner Chiesi Global Rare Diseases expressed their continued commitment to reducing treatment burden for patients with Fabry disease. Elfabrio is a recombinant therapeutic protein produced by Protalix’s proprietary ProCellEx plant cell-based protein expression system.

"We are disappointed by the result of this review but want to express our immense appreciation for the collaboration of the patient community, researchers and European Commission throughout this process," said Giacomo Chiesi, Executive Vice President of Chiesi Global Rare Diseases.

Dror Bashan, Protalix’s President and CEO, added that the companies remain committed to their priority of reducing treatment burden for Fabry disease patients despite this regulatory outcome.

The companies stated they intend to continue working together to support the Fabry disease community.

This article was generated with the support of AI and reviewed by an editor. For more information see our T&C.

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