The FDA has acknowledged receipt of the Nov. 25 amendment from Salix Pharmaceuticals regarding its Rifaximin New Drug Application (NDA).

The FDA says it considers the amendment to be a “complete response” to the Oct. 25, 2002, approvable letter seeking additional clinical data. The agency has assigned a date of May 26, 2004, to review and act upon the NDA.

Salix initially is seeking approval to market Rifaximin, a non-systemic, gastrointestinal site-specific antibiotic, as a treatment for travelers’ diarrhea.

The Raleigh-based company projects up to $500 million in annual sales for Rifaximin within three to five years.

Shares of Salix (Nasdaq: SLXP) surged almost four percent to $20.60, an 76-cent increase over yesterday’s close of $19.84, at midday. it closed at $19.88, up 4 cents. The stock’s 52-week range is from a low of $5 to a high of $21.53