Appeal type: Medical necessity
Decision: Overturned

Diagnosis: Small intestinal bacterial overgrowth (SIBO).

Treatment: Xifaxan

The insurer denied coverage for Xifaxan. The denial is reversed. 

This patient is a male who developed abdominal pain and diarrhea. He has had several tests done that were normal including stool cultures. A breath test was positive for small intestinal bacterial overgrowth (SIBO). The treating provider wants to treat with Xifaxan 550 mg three times a day (TID) for 14 days.

Per Chey, W. D., Shah, E. D., & DuPont, H. L. (2020), "Irritable bowel syndrome (IBS) is a common functional gastrointestinal disorder with a multifactorial pathophysiology. The gut microbiota differs between patients with IBS and healthy individuals. After a bout of acute gastroenteritis, postinfection IBS may result in up to approximately 10% of those affected. Small intestinal bacterial overgrowth (SIBO) is more common in patients with IBS than in healthy individuals, and eradication of SIBO with systemic antibiotics has decreased symptoms of IBS in some patients with IBS and SIBO...The efficacy and safety of 2-week single and repeat courses of rifaximin have been demonstrated in randomized, placebo-controlled studies of adults with IBS. Rifaximin is widely thought to exert its beneficial clinical effects in IBS-D through manipulation of the gut microbiota."

Per Pimentel M. (2016), "Rifaximin was approved in 2015 for the treatment of IBS with diarrhoea. In contrast to other currently available IBS therapies that require daily administration to maintain efficacy, 2-week rifaximin treatment achieved symptom improvement that persisted 12 weeks post-treatment. The mechanisms of action of rifaximin, therefore, may extend beyond direct bactericidal effects. Data suggest that rifaximin may decrease host proinflammatory responses to bacterial products in patients with IBS. In some cases, small intestinal bacterial overgrowth (SIBO) may play a role in the clinical symptoms of IBS. Because of the high level of solubility of rifaximin in the small intestine, rifaximin may reset microbial diversity in this environment. Consistent with this hypothesis, rifaximin has antibiotic efficacy against isolates derived from patients with SIBO."

Per Lembo, A., Pimentel, M., Rao, S. S., Schoenfeld, P., Cash, B., Weinstock, L. B., Paterson, C., Bortey, E., & Forbes, W. P. (2016), "Of 1074 patients (44.1%) who responded to open-label rifaximin, 382 (35.6%) did not relapse and 692 (64.4%) did; of these, 636 were randomly assigned to receive repeat treatment with rifaximin (n = 328) or placebo (n = 308). Significant improvements were also noted for prevention of recurrence, durable response, and bowel movement urgency. Adverse event rates were low and similar between groups."    

The request for Xifaxan is medically necessary, therefore, the health care plan did not act reasonably and with sound medical judgment and in the best interest of the patient. Small intestinal bacterial overgrowth (SIBO) occurs when colonic type bacteria grow in large numbers in the small bowel. There is a wide variety of clinical manifestations that can be caused by SIBO including no symptoms, abdominal pain, diarrhea, fat malabsorption, disaccharidase deficiency, protein losing enteropathy, iron loss, vitamin B12 deficiency.  Xifaxan is not being used for the convenience of the patient or the doctor. Xifaxan has been shown to be safe and effective for SIBO and IBS-D and is often used off-label by pediatric gastroenterologists. Therefore, Xifaxan is medically necessary for this particular patient.

Based on the above, the medical necessity for Xifaxan five hundred fifty milligrams (550mg) tablet, quantity of forty-two every fourteen (42/14) days is substantiated.  The insurer's denial is reversed.