Crohn’s is a complex and chronic inflammatory bowel disease that affects the entire digestive tract. Medications address painful symptoms, like intestinal ulcers and inflammation. Other therapies can put the disease into remission. If Dr. Hermon-Taylor’s research is successful, a simple — and cost-effective — cure may be on the horizon. The retired physician and molecular scientist has devoted a great deal of his career to studying the microbiology of inflammatory bowel disease (IBD). After decades of research, he has concluded that Crohn’s may be caused by a single bacterium — Mycobacterium avium subspecies paratuberculosis, or MAP, which he reported on in a review published July 2009 in the journal Gut Pathogens. Unlike most vaccines, what Hermon-Taylor has developed is designed to be both preventive and therapeutic. His vaccine targets MAP by training the immune system to destroy it. This will not only keep healthy people from developing Crohn’s, but also give relief to Crohn’s patients. According to his theory, once the body is free of this bacterium, it will no longer produce the inflammatory response that causes so much pain for those with Crohn’s. “If it does in humans what it did in preclinical animal trials, the vaccine could have significant benefits for people with Crohn’s disease,” Hermon-Taylor says.
The Connection Between Crohn’s Disease and MAP
A relative of both tuberculosis and leprosy, MAP was first observed in cattle in 1894, by the German bacteriologist and veterinarian Heinrich A. Johne. The bacterium wreaks havoc on the animals’ digestive tracts, inducing ulcers and inflammation that resemble that of Crohn’s. MAP then travels to human hosts through milk, or through water tainted by cow dung. “A major part of our work has been developing a way to detect the organism in human patients. We’ve found that every single Crohn’s patient we studied is infected with MAP,” Hermon-Taylor says, noting that in a recent study, his team examined tissue samples from more than 70 patients. They will be publishing the study’s results later this year. The high incidence of MAP in Crohn’s patients led him to believe that it plays an important role in the disease’s development. In cows and humans alike, Hermon-Taylor’s website argues, “[MAP] initiates a cascade of events with disastrous consequences.” The bacterium’s effect on the immune system destabilizes the walls of the gut, making it vulnerable to secondary infections and irritants. That’s what gives rise to an extreme intestinal inflammatory response, the hallmark of Crohn’s disease. Treatments dampen that response and temporarily ease symptoms. But Hermon-Taylor emphasized that “unless you treat MAP itself, you are only treating the symptoms, not the cause.” In cattle, inoculating against MAP has proved remarkably effective, according to a study published in October 2014 in Veterinary Research. The vaccine trains cows’ immune systems to kill off MAP in their guts, in many cases leading to permanent relief. The tantalizing question: Might it also work for people?
What Outside Experts Say About the MAP Theory
Experts on Crohn’s disease are divided about MAP’s role. Helen Fasanya-Uptagraft, MD, a gastroenterologist at Midwest Gastrointestinal Associates, in Omaha, Nebraska, is intrigued. “Crohn’s and tuberculosis come with some similarities in presentation, so a bacterial etiology like this makes sense,” she says. “I’m optimistic about the prospect of a cure.” Work from Saleh Naser, PhD, an infectious disease specialist at the University of Central Florida in Orlando, also bodes well for the theory. In 2004 he developed a means to test the blood of Crohn’s patients for the presence of MAP. His own research comports with Hermon-Taylor’s findings: Of the 30 patients he sampled, all 30 presented with MAP. Right now, Dr. Naser is working with a team of researchers at RedHill Biopharma to develop an oral antibiotic that specifically targets MAP in Crohn’s patients. The pill, called RHB-104, is currently undergoing an international phase 3 (large scale) clinical trial, with results to come in September 2018. This treatment, too, has curative potential — but further trials will be needed to confirm its lasting effects. In a presentation to RedHill’s investors, David Graham, MD, the lead investigator on RedHill’s MAP study in the United States, said that if RHB-104 successfully heals intestinal lesions caused by Crohn’s, that would likely confirm the anti-MAP hypothesis to be true. Others in the field, however, are not quite ready to endorse the MAP theory. Skeptics challenge the identification of MAP as the lone cause of Crohn’s. They argue that the illness is too complex to have just one culprit. Benjamin Hall, MD, a gastroenterologist in Omaha (and also a Crohn’s patient), expressed some doubts. “We’ve heard about these kind of silver bullets before,” Dr. Hall says. “And once the research is done, the numbers usually don’t bear them out. Crohn’s is multifactorial and complicated. I don’t think we’re going to see any one single cause of it [or cure for it].” Aaron Castens, the executive director of the Crohn’s and Colitis Foundation of the Midwest, echoed Hall’s caution. It’s the Foundation’s official position that MAP “may play a role in the development of Crohn’s disease as one of many different microbes that might act as a trigger for an abnormal inflammatory response,” he says, “but until more convincing scientific proof emerges, it cannot be described as a primary or the sole cause of Crohn’s disease.” Hermon-Taylor is undeterred. “It’s true that Crohn’s disease is complex — but so was leprosy. All of these ailments are difficult to understand until we learn what causes them,” he says. Answering the skepticism will require significant clinical results, which the professor and his organization, Crohn’s MAP Vaccine, are doggedly pursuing. It has not been easy, because MAP is a uniquely resilient bug. Even pasteurization fails to kill it off completely, which is why people can contract it from drinking milk. It took 10 years for Herman-Taylor — and other scientists between London and Oxford University — to develop an effective vaccine against it, according to research published in PLoS One. For all their efforts, the vaccine hasn’t attracted investment from drug makers. Instead, hopeful Crohn’s patients and their families donated the majority of the project’s expense, around £850,000 ($1.2 million). Results for Hermon-Taylor’s vaccine trial will be announced in March of 2019. Until then, no one can say for certain whether he has succeeded. “I’d like nothing better than to deliver good news to Crohn’s sufferers, but right now we don’t know if the vaccine can cure,” Hermon-Taylor said. “But from what we know about how the organism presents in humans, the odds are better than an even split, I’d say.” For Crohn’s patients, those are the best odds they’ve heard of in a long time.
