Appeal type: Medical necessity
Decision: Upheld

Diagnosis: Digestive System/Gastrointestinal
Treatment: Pharmacy/Prescription Drug
The insurer denied the Xifaxan.
The determination is upheld.


The patient has chronic diarrhea. The medical records provided do not indicate that she has tried and failed antidiarrheal medications, antispasmodics or tricyclic anti- depressants. The attending provider is requesting the use of Xifaxan (rifaximin) at the dose of 550 milligrams (mg) twice a day to treat this patient's diarrhea which he feels is due to irritable bowel syndrome with diarrhea (IBS-D). The patient has apparently been treated with Xifaxan in the past, but it is not known when she was last treated and how many courses of Xifaxan she has had.
At issue is the medical necessity of the Xifaxan.
The requested health service/treatment of Xifaxan 550 mg tablets is not medically necessary for this patient.
Irritable bowel syndrome (IBS) is a common gastrointestinal condition whose cause remains unknown. Therefore, treatment of IBS has been based on a symptom approach. Recent evidence is beginning to suggest that patients with IBS may have an alteration in gastrointestinal flora. Specifically, findings suggest that IBS patients have excessive bacteria in the small bowel, known as bacterial overgrowth. Antibiotic-based therapies for IBS are now shown to be very effective in treating IBS. Rifaximin is a non-absorbed derivative of rifamycin with a broad-spectrum antibiotic activity against gram-positive and gram-negative organisms. It has been approved by the Food and Drug Administration (FDA) for the treatment of travelers' diarrhea due to non-invasive Escherichia coli, and has been approved for reduction in risk of overt hepatic encephalopathy (HE) recurrence inpatients greater than 18 years of age. Pimentel et al, conducted two identically designed, phase 3, double-blind, placebo-controlled trials (TARGET 1 and TARGET 2), patients who had IBS without constipation were randomly assigned to either rifaximin at a dose of 550 mg or placebo, three times daily for 2 weeks, and were followed for an additional 10 weeks. Among patients who had IBS without constipation, treatment with rifaximin for 2 weeks provided significant relief of IBS symptoms, bloating, abdominal pain, and loose or watery stools. Thus, treatment with rifaximin at a dose of 550 mg three times daily for 14 days provides better relief of IBS symptoms than placebo for up to 10 weeks after completion of therapy. Rifaximin improved global symptoms in 92% of patients and eradicated Small Intestinal Bacterial Overgrowth (SIBO) in up to 84% of patients with irritable bowel syndrome, with results sustained up to 10 weeks post-treatment. Rifaximin caused a lower number of adverse events compared with metronidazole or levofloxacin and may have a more favorable adverse event profile than systemic antibiotics, without clinically relevant antibiotic resistance. As of May 27, 2015, Xifaxan is FDA approved at the dose 550 mg three times daily for IBS-D based on data from three phase 3 studies, TARGET 1, TARGET 2 and TARGET 3. Xifaxan 550 mg was studied in over 3,000 patients and demonstrated the efficacy and safety of repeat treatment following completion of a two-week course of treatment. [Per the FDA Label for Xifaxan: https://www.accessdata.fda.gov/drugsatfda_docs/label/2015/021361s012lbledt.pdf] Patients who experience recurrence can be retreated up to two times with the same regimen. However, there are no data in the published literature to show that Xifaxan may be used twice a day indefinitely to treat IBS-D and therefore, Xifaxan cannot be approved for at this dose and for this duration.
Additionally, since this patient has not tried and failed tricyclic anti-depressants, anti-diarrheals and antispasmodics and does not have a contraindication to these medications, Xifaxan is not medically necessary.