Protalix BioTherapeutics, Inc. announced that it has submitted its reply to the Complete Response Letter issued in February 2011 by the US Food and Drug Administration (FDA) after its review of the Company’s New Drug Application (NDA) for taliglucerase alfa. Taliglucerase alfa, the company’s proprietary plant-cell expressed form of glucocerebrosidase (GCD), is in development for the treatment of Gaucher disease.

“We believe we have adequately addressed the requests that were outlined by the FDA in their Complete Response Letter,” said Dr David Aviezer, president and CEO of Protalix. “We will continue to work closely with the FDA as it moves forward with the NDA review.”

On November 30, 2009, Pfizer and Protalix BioTherapeutics, Inc. entered into an agreement to develop and commercialize taliglucerase alfa.

The Company's submission addresses the issues identified by the FDA in the Complete Response Letter, including the request for clinical data from the Company’s switchover trial and long-term extension trial, and additional information relating to chemistry, manufacturing and controls (CMC).

Data from all twenty six adult patients enrolled in the Company’s switchover trial of patients switched from Cerezyme to taliglucerase alfa over the nine-month period, were included in the submission. The data supports the efficacy and safety data package showing that patients can be switched from imiglucerase (Cerezyme) to taliglucerase alfa. One patient experienced a hypersensitivity reaction. The efficacy data demonstrates that mean haemoglobin and platelet count, spleen volume and liver volume remained stable. Patients enrolled in the trial were switched from imiglucerase (doses ranging from around 10-60 U/kg every other week) to an equivalent dose using the same number of units of taliglucerase alfa.

The submission also included data from treatment naïve patients who completed the Company’s pivotal phase III trial and have continued to receive taliglucerase alfa for over 24 months in the company’s blinded long-term extension trial. These patients continued to show an improvement in efficacy and the drug was safe and well tolerated. Furthermore, those patients who were followed specifically for their bone parameters using Quantitative Chemical Shift Imaging (QCSI) MRI continued to show bone marrow improvement over time. Detailed data from the Company’s switchover trial and long-term extension trial will be presented at upcoming medical meetings.

Regarding CMC, Protalix submitted further analyses and modifications of analyses previously submitted to the FDA to address their questions raised with regard to testing specifications and assay validation.

The Company expects the FDA to provide an updated Prescription Drug User Fee Act (PDUFA) target action date within weeks, which is consistent with FDA guidelines.

Protalix is a biopharmaceutical company focused on the development and commercialization of recombinant therapeutic proteins expressed through its proprietary plant cell based expression system, ProCellEx.