Intestinal worms may resolve Crohn's, IBD.
In a study of 29 patients with Crohn's disease, ingesting a dose of helminth eggs every 3 weeks led to a 72% remission rate after 24 weeks, Dr. Robert W. Summers reported at the annual Digestive Disease Week. And in a second study with 54 patients, dosing with the same type of worm eggs every 2 weeks led to a 48% response rate during 12 weeks of treatment, said Dr. Summers, the James A. Clifton professor and director of clinical programs for the gastroenterology division at the University of Iowa in Iowa City.
"Helminths have a unique property of causing long-lasting modulation of the immune system," commented Dr. Joel V. Weinstock, professor and director of gastroenterology-hepatology at the university and a coinvestigator on these studies. "Inflammatory bowel disease and other common immune diseases in industrialized countries seem to be diseases of the 20th century that are very rare in less developed countries. I predict that helminths may also be a factor in asthma, multiple sclerosis, and other immunologic diseases."
The helminth selected for initial clinical study was Trichuris suis, a porcine whipworm that can colonize for several weeks in humans but cannot multiply, because it is not a natural human parasite. It is not directly transmissible from one person to another. So far, this treatment has been developed with support from the University of Iowa, the National Institutes of Health, and charitable foundations. Helminth treatment has not yet been commercialized.
In the Crohn's disease study, 29 patients with a Crohn's disease activity index score of 220-450 were enrolled, and 25 finished the study. In this open-label study, each patient ingested 2,500 T. suis ova every 3 weeks for 24 weeks. After 12 weeks, the response rate was 75.9% and the remission rate was 62.1%. After 24 weeks, these rates had risen to 79.3% and 72.4%, respectively, said Dr. Summers. There were no adverse effects or complications from therapy.
The ulcerative colitis study involved 54 patients with a disease activity score of at least 4. Patients were treated with either 2,500 T. suis ova or placebo every 2 weeks for 12 weeks, then the two study groups were crossed over and the patients took the new regimens for another 12 weeks.
Combined data from both 12-week treatment groups showed that the 47.8% response rate among patients treated with helminths was significantly better than the 15.4% response rate during placebo treatment, Dr. Summers reported in a separate presentation at the meeting.
In this initial clinical study, the dosing regimens, as well as the type of helminth administered, were not yet optimized, Dr. Summers added.
"This is a prototype," Dr. Weinstock said. "It likely works by a novel mechanism. It has the potential to give us real insight into the causes of inflammatory bowel disease and perhaps new insights into how to treat and prevent inflammatory bowel disease," he said.
BY MITCHEL L. ZOLER