Salix Pharmaceuticals, Ltd. (NASDAQ:SLXP) announced that the U.S. Food and Drug Administration (FDA) issued a Complete Response Letter (CRL) on March 7, 2011 for the supplemental New Drug Application (sNDA) for XIFAXAN® (rifaximin) 550 mg tablets for the proposed indication of treatment of non-constipation irritable bowel syndrome (Non-C IBS) and IBS-related bloating. The CRL reconfirms the Company's understanding that the FDA deems the XIFAXAN 550 mg sNDA for non-C IBS is not ready for approval primarily due to a newly expressed need for retreatment information, as stated in the Company's February 24, 2011 press release. The Company received the CRL at approximately 8:00 p.m. ET on Monday, March 7, 2011.

At this time, the Company intends to request a Type A meeting with the Agency to discuss the XIFAXAN 550 mg sNDA for non-C IBS. Type A meetings should be scheduled to occur within 30 days of FDA receipt of a written meeting request submitted by a Sponsor. Until the Type A meeting is held and the Company has the opportunity to evaluate its options, the Company cannot begin to formulate future development plans for non-C IBS. The Company plans to provide its next update during the Company's first quarter 2011 earnings call to be scheduled for early May 2011.

About XIFAXAN® (rifaximin )

Rifaximin is a gut-selective antibiotic with negligible systemic absorption and broad-spectrum activity in vitro against both gram-positive and gram-negative pathogens. Rifaximin has a similar tolerability profile to that of placebo.

Rifaximin tablets 200 mg is approved in over 30 countries worldwide. Alfa Wassermann S.p.A. in Bologna, Italy has marketed rifaximin in Italy under the trade name Normix® for over 30 years. Salix acquired rights to market rifaximin in North America from Alfa Wassermann.

Important Safety Information

XIFAXAN 550 mg tablets are indicated for reduction in risk of overt hepatic encephalopathy (HE) recurrence in patients ≥ 18 years of age. In the trials of XIFAXAN 550 mg tablets for HE, 91 percent of the patients were using lactulose concomitantly. XIFAXAN 550 mg tablets have not been studied in patients with MELD scores > 25, and only 8.6 percent of patients in the controlled trial had MELD scores over 19. There is increased systemic exposure in patients with more severe hepatic dysfunction. Therefore, caution should be exercised when administering XIFAXAN 550 mg tablets to patients with severe hepatic impairment (Child-Pugh C).

XIFAXAN 550 mg tablets are contraindicated in patients with a hypersensitivity to rifaximin, any of the rifamycin antimicrobial agents, or any of the components in XIFAXAN 550 mg tablets. Hypersensitivity reactions have included exfoliative dermatitis, angioneurotic edema, and anaphylaxis.

Clostridium difficile-associated diarrhea (CDAD) has been reported with use of nearly all antibacterial agents, including XIFAXAN 550 mg tablets, and may range in severity from mild diarrhea to fatal colitis. Treatment with antibacterial agents alters the normal flora of the colon which may lead to overgrowth of C. difficile. If CDAD is suspected or confirmed, ongoing antibiotic use not directed against C. difficile may need to be discontinued.

The most common adverse reactions occurring in >8 percent of patients in the clinical study were edema peripheral (15 percent), nausea (14 percent), dizziness (13 percent), fatigue (12 percent), ascites (11 percent), muscle spasms (9 percent), pruritus (9 percent), and abdominal pain (9 percent).

Source:
Salix Pharmaceuticals, Ltd.