Date: 30-May-2020

Protalix BioTherapeutics And Chiesi Global Rare Diseases Announce Submission Of Biologics License Application To US Food And Drug Administration For P

Protalix BioTherapeutics, Inc. (NYSE American: PLX) (TASE: PLX), a biopharmaceutical company focused on the development, production and commercialization of recombinant therapeutic proteins produced by its proprietary ProCellEx® plant cell-based protein expression system, or the Company, together with its development and commercialization partner Chiesi Global Rare Diseases, a unit of Chiesi, an international research-focused healthcare group, today announced the submission on May 27, 2020 of a Biologics License Application (BLA) to the U.S. Food and Drug Administration (FDA) for pegunigalsidase alfa for the proposed treatment of adult patients with Fabry disease via the FDA's Accelerated Approval pathway. Pegunigalsidase alfa, or PRX-102, was granted Fast Track designation by the FDA in January 2018. Pegunigalsidase alfa is the Company's purposefully-designed, long-acting recombinant, PEGylated, cross-linked α-galactosidase-A investigational product candidate.The BLA submission includes a comprehensive set of preclinical, clinical and manufacturing data compiled from the Company's completed Phase I/II clinical trial of pegunigalsidase alfa, including the related extension study succeeding the Phase I/II clinical trial, interim clinical data from the Phase III BRIDGE switch-over study and safety data from the Company's on-going clinical studies of PRX‑102. Upon the BLA approval, if approved, the Company will be eligible to receive a milestone payment from Chiesi.

"We are grateful for the assistance the FDA provided leading up to the submission of this BLA via the Accelerated Approval pathway, and we look forward, together with Chiesi, to working with the FDA as we seek marketing approval for PRX‑102," said Dror Bashan, Protalix's President and Chief Executive Officer. "Together with Chiesi, we thank the investigators and study participants who have made reaching this milestone possible and have supported Protalix in our commitment to bringing this new treatment option to the Fabry patient community."

"The submission of this BLA to the FDA represents a significant milestone for our Global Rare Diseases division that was established earlier this year to strengthen Chiesi's focus on making a difference for patients living with rare diseases around the world," said Giacomo Chiesi, head of Chiesi Global Rare Diseases. "Our partnership and active collaboration with Protalix are a great example showing how we can leverage Chiesi's global reach and decades of experience in drug development to support patients and their families living with Fabry disease and many other devastating rare diseases."

About Fabry Disease

Fabry disease is an X-linked inherited disease that results from deficient activity of the lysosomal α‑Galactosidase‑A enzyme resulting in progressive accumulation of abnormal deposits of a fatty substance called globotriaosylceramide (Gb3) in blood vessel walls throughout a person's body. Fabry disease occurs in one person per 40,000 to 60,000. Fabry patients inherit a deficiency of the α‑Galactosidase‑A enzyme, which is normally responsible for the breakdown of Gb3. The abnormal storage of Gb3 increases with time and, accordingly, Gb3 accumulates, primarily in the blood and in the blood vessel walls. The ultimate consequences of Gb3 deposition range 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.

About Pegunigalsidase Alfa

Pegunigalsidase alfa (PRX‑102) is an investigational, plant cell culture-expressed, and chemically modified stabilized version of the recombinant α-Galactosidase-A enzyme. Protein sub-units are covalently bound via chemical cross-linking using short PEG moieties, resulting in a molecule with unique pharmacokinetic parameters. 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.