A new test and a new treatment recently approved by the FDA will for the first time allow physicians to definitively diagnose and treat patients who may be suffering from irritable bowel syndrome (IBS) according to Gastro One gastroenterologist Edward Cattau, MD.
“It’s going to significantly alter our approach to IBS,” Cattau said.
Named IBSchek, the test determines the existence of two antibodies in the bloodstream. Developed out of a multi-center Cedars-Sinai clinical trial with Commonwealth Medical Laboratories, it tests for anti-CdtB (cytolethal distending toxin B) and anti-vinculin, two antibodies produced by the immune system that are triggered by food poisoning leading to IBS symptoms like diarrhea.
This is the first scientifically proven cause of IBS and a “complete paradigm shift” for patients, according to Cattau. Before the test, Cattau and other gastroenterologists would test patients with IBS symptoms for other conditions, leaving them with an IBS diagnosis by exclusion.
“Now, patients come in with symptoms and we can simply do the IBSchek, and if it’s positive we can treat them and avoid expensive and invasive tests like a colonoscopy,” Cattau said. “One study suggests we can save about $500 per patient, not to mention rapidly obtain a diagnosis.”
The results from IBSchek are ready within 24 hours of the blood test reaching Commonwealth Labs.
Once diagnosed, patients can be treated with the antibiotic Xifaxan (rifaximin).
Physicians at Cedars-Sinai Hospital led by Mark Pimentel, MD, first saw a connection between bacteria and IBS when some of their patients with diarrhea-dominant IBS symptoms responded positively to a treatment of antibiotics. The nearly 3,000 patient study compared blood test results of patients with inflammatory bowel disease, celiac disease and those without GI disease. The anti-CdtB and anti-vinculin antibodies were found in test participants with IBS symptoms, with over 90 percent certainty.
Cattau likens the antibody secretion in response to certain types of food poisoning to autoimmune disease resulting in damage to the small intestine. As the body tries to fight the infection, antibodies are made to neutralize the toxin called cytolethal distending toxin B (CdtB). The new test can measure anti-CdtB levels to determine if patients have the antibodies.
Through a process called molecular mimicry, the body also makes antibodies to vinculin thinking it’s the toxin, damaging the nervous system of the small intestine and causing excess bacteria. This bacteria overgrowth results in the discomfort and diarrhea that patients experience.
In May, the FDA approved antibiotic for the treatment of diarrhea-dominant IBS, Xifaxan.
Xifaxan treats the bacterial overgrowth antibodies causing IBS diarrhea dominant symptoms. The antibiotic suppresses the excess bacteria after one or two rounds of therapy. Cattau is seeing success with the new antibiotic treatment following an IBSchek test.
“Sixty to sixty-five percent of patients I’ve tested have a positive test and almost all have responded to antibiotic treatment” he says.
There are three types of IBS – IBS-D (diarrhea predominant), IBS-C (constipation predominant) and IBC-M (mixed diarrhea and constipation). The majority of IBS patients have IBS-D, which can now be quickly diagnosed with IBSchek.
Case Western Reserve University School of Medicine estimates the annual cost of IBS in the U.S. is around $30 billion for direct medical treatment and indirect costs. It is estimated that 10- 15 percent of the population has IBS but only the minority, around 15 percent are diagnosed. Pimentel notes that patients with IBS “have been told at one time or another that the disease was psychological, all in their head. The fact that we can now confirm the disease through their blood, not their head, is going to end a lot of the emotional suffering I have seen these patients endure.”
Cattau states a significant number of his patients are referrals from primary care physicians who are unsure of the diagnosis of IBS based on symptoms alone. Many patients visit several doctors without a clear diagnosis. With IBSchek, primary care physicians can easily test patients and prescribe Xifaxan if the test is positive, saving time and money for patients.
IBSchek is a game-changer for those suffering with IBS-D and some with IBS-M, but it will not help patients with IBS-C, who are estimated to make up 30 percent of patients with IBS symptoms.
Cattau is looking forward to continued research on the blood testing of IBS-D patients to see if those with negative IBSchek results will respond to a motility drug versus an antibiotic treatment.
Additionally, more research is needed on the antibiotic treatment course for patients with recurrent symptoms after a round of medication. Cattau predicts “some patients might be better served by a low-dose over the long term, versus recurrent two-weeks of therapy.”
That study should be out next year. With continued research, gastroenterologists can customize therapy for IBS patients for effective, long-term treatments.
RELATED LINKS:
Print
