Porcine Whipworm Ova Safe for Treatment of IBD

Mindy Hung

September 26, 2003

Sept. 26, 2003 — Administering eggs from the porcine whipworm Trichuris suis to patients with Crohn's disease (CD) and ulcerative colitis (UC) is a safe and possibly effective treatment for inflammatory bowel disease (IBD) according to a small study published in the September issue of the American Journal of Gastroenterology.

"Intestinal helminthes induce Th2 cytokine release and specifically downregulate Th1 responsiveness," write Robert W. Summers, MD, and colleagues from University of Iowa Health Care in Iowa City.

"IBD is rare in developing countries with less clean environments and more crowded living conditions. The explanation for this difference in prevalence has always been speculative, but it should be noted that the prevalence of IBD is inversely proportional to the prevalence of helminthic parasites in that population," they add.

Investigators selected three patients with active symptomatic UC manifested by bleeding or diarrhea, active inflammation on flexible signoidoscopy, and four patients with active Crohn's colitis on colonoscopy and a Crohn's Disease Activity Index (CDAI) greater than 180. All patients had their disease for five years or longer.

Five patients had been treated with high-dose prednisone (≥ 40 mg), 6-mercaptopurine/azathioprine, or both during the preceding year without benefit. Two patients could not be treated with 6-mercaptopurine or azathioprine because of prior pancreatitis associated with these drugs. Patients continued on their medications at the same dosage throughout the study.

The authors excluded subjects with fulminant colitis or a CDAI less than 220; an ileostomy or colostomy; an extensive resection of bowel; the need for surgery; cancer; history of substance abuse; stools positive for pathogens, ova, or parasites; Clostridium difficile toxin; significant concurrent infection; and severe or progressive systemic diseases.

Investigators harvested eggs from cultured worms, washed them, and checked them for bacterial and viral pathogens. After performing baseline studies on blood count and hepatic enzymes and bilirubin, the authors administered a single dose of 2500 live T. suis eggs orally to the patients with 30 mL of Gatorade.

Dr. Summers and colleagues monitored patients' follow-up efficacy responses, as well as their clinical status and laboratory status every two weeks for 12 weeks. Investigators also tracked subjects' progress using the CDAI, the Simple Clinical Colitis Acitivity Index (SCCAI), and the Inflammatory Bowel Diseases Quality of Life Index (IBDQ).

During the 12-week treatment and observation period, only one of the four CD patients experienced a clinical response without remission, according to the CDAI, while the other three patients entered remission. Patients with UC experienced a reduction of the CCAI to 57% of baseline.

Six (86%) of seven patients achieved remission according to the IBDQ. However, the investigators note that three of the six patients relapsed within 12 weeks after the single dose according to the CDAI or SCCAI.

After the initial treatment and observation period, the authors administered multiple doses of ova to four patients (two with UC and two with CD) at three-week intervals for a maintenance period of at least 30 weeks. The patients did not experience detectable adverse effects or clinically significant changes from ingestion of the ova.

Of the patients who did not participate in long-term maintenance, one patient underwent prolonged remission for seven months when he moved to another state. The other two subjects were unreliable in their follow-up.

The investigators acknowledge that the observations may represent a placebo response. "We recognize that a larger double-blind, placebo-controlled study is important and necessary to establish helminthic colonization as a safe and effective therapy for IBD," they add.

Preliminary results of this work were presented at the 100th annual meeting of the American Gastroenterological Assocation in May 1999.

This work was supported by grants from the Crohn's and Colitis Foundation of America, the National Institutes of Health, and by a gift from the Thomas Irwin Memorial Fund.

Am J Gastroenterol. 2003;98:2034-2041

Reviewed by Gary D. Vogin, MD

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