Xifaxan and its manufacturer, Salix, has been making news all week. An FDA advisory panel recently recommended the approval of Xifaxan in 550 mg tablets, as an Orphan Drug for the maintenance of remission of hepatic encephalopathy (HE,) a dangerous result of liver failure.
Xifaxan or Rifaximin, is almost always the front line antibiotic used to eradicate SIBO. According to the literature, it has many advantages over other antibiotics. As a broad-spectrum, non-absorbable antibiotic, it is not absorbed into the bloodstream and it acts against both gram-positive and gram-negative pathogens. In many trials, the administration of Rifaxamin has produced a very low occurrence of side effects and additionally the risk of antibiotic resistance is lower with Rifaxamin than with many other antibiotics. Probably the most unique property of Rifaxamin, and also what makes it most useful to people with SIBO, is its demonstrated efficacy against bloating! It has also been used to reduce or eliminate cutaneous lesions in Rosacea patients with SIBO.
To be honest I am unclear of the FDA’s recommendation for people with SIBO. If there is an impact, what does the drug’s status as an orphan drug mean for SIBO?
According to Wikipedia, the Orphan Drug Act is “meant to encourage pharmaceutical companies to develop drugs for diseases that have a small market.” That is certainly SIBO! However, orphan drugs have to treat orphan diseases; conditions that affect fewer than 200,000 people in the United States. I have no idea how many people in the United States suffer from SIBO. During holidays and office birthday parties when I watch everyone eat candy I feel like I may be the only SIBO patient in the nation.
It may not matter whether or not SIBO is an orphan disease. Just a day before the news broke of the FDA recommendation, an article discussing the deliberation noted that Salix is planning to submit a new drug application for Xifaxan this year, specifically for the irritable bowel syndrome indication in the first half of 2010.
Currently, Xifaxan is prescribed to people with SIBO off-label. The developments of Salix’s new application for Xifaxan for IBS will be of some interest to the SIBO community because if it is approved then Xifaxan could be prescribed specifically for SIBO. Xifaxan has not worked for all of us; I have taken several courses and sometimes it works and sometimes it doesn’t. However, the largest issue with Xifaxan for SIBO is the prohibitively high cost. Most insurance companies just don’t cover drugs when they are used off-label. If Salix’s application is approved, more people with SIBO will at least be able to try Xifaxan. Which, I believe is a good thing. It is interesting to note that there were questions of both efficacy and safety during the HE study, and the SIBO community should be on the lookout to see if these same issues arise during the IBS studies.