The FDA has issued a complete response letter for Protalix's Gaucher's disease drug taliglucerase alfa. Protalix won't be required to conduct any additional clinical studies, but that didn't stop its stock from plunging on the news, FierceBiotech reported.

The FDA's main concerns were with clinical and chemistry, manufacturing and controls. The agency wants additional data from Protalix's switchover trial and long-term extension trial. At the time the NDA was submitted, full information from these trials was not available, the company noted in a release. The FDA wants information on testing specifications and assay validation.

"While we are disappointed by the receipt of the Complete Response Letter, we appreciate the FDA's efforts to complete the review of our NDA,” said Protalix CEO David Aviezer. “We noted that the FDA did not request additional clinical studies. Moreover, the FDA inspected our manufacturing facilities, finding them acceptable. FDA also did not identify any issues in its audit of our clinical sites." The company said it will meet with the FDA to determine its next steps.

Gaucher's is a rare genetic disease in which lipids accumulate in the organs, resulting in organ enlargement and bone pain. Pfizer has partnered with Protalix since 2009 on the drug, an oral recombinant protein therapeutic. If approved, taliglucerase alfa could erode market share of Genzyme's Cerezyme, which has faced shortages due to manufacturing problems.