Researchers at the Fred Hutchinson Cancer Research Center were approved to begin a trial to test whether a bone-marrow transplant from a healthy donor can cure patients with severe Crohn’s disease by giving them a new immune system.
In a bold experiment, Seattle researchers are seeking to cure severe Crohn’s disease by giving patients a new immune system.
The clinical trial, which just received final approvals, will take a closer look at a side effect of bone-marrow transplantation that researchers at the Fred Hutchinson Cancer Research Center noticed years ago: A handful of leukemia patients given donor marrow cells were also cured of their Crohn’s disease, a chronic intestinal inflammation.
Essentially, the idea behind the new study is simple: “It’s swapping out an old, diseased immune system for a new immune system, which we hope — and our research would support — will take care of the Crohn’s disease,” said Dr. George McDonald, the study’s principal investigator.
McDonald, a transplant researcher and gastroenterologist, said until recently, it was unthinkable to offer a bone-marrow transplant for a non-life-threatening disease.
I’ve been waiting to do this protocol for 20 years, but only recently have our outcomes gotten to the point where I think it’s a good balance between risk and benefits,” McDonald said.
In a study published in the New England Journal of Medicine in 2010, McDonald concluded patients who had a bone-marrow transplant from 2003 to 2007 were much more likely to live long-term than those who underwent the procedure in the 1990s.
Even so, a bone-marrow transplant is not without risks to patients. In this study, it will be offered only to those with the most devastating, untreatable form of the disease, believed to be caused by an abnormal immune response to intestinal bacteria that is rooted in genetic abnormalities.
“This is something we’ve thought very hard about — the ethics of this,” McDonald said. “The ethical equipoise of this protocol is not life versus death, it’s continued misery versus curing the disease.”
McDonald said the Crohn’s & Colitis Foundation of America estimates that about 700,000 Americans live with Crohn’s disease, which can cause pain, fever, diarrhea and weight loss. For most, medications control the disease, but a small fraction has found no relief.
Those are the people McDonald and his team are hoping to find for the very small Phase 2 clinical trial now under way. Patients must be between 18 and 60 years old with severe Crohn’s disease unresponsive to conventional treatments, but otherwise healthy.
Even for patients who meet the criteria, McDonald said, there will be challenges. For one thing, their insurers have to agree to cover the transplant and related medical expenses.
Then, the study will have to find matched bone marrow from a patient’s sibling or an unrelated donor.
Linda Huse, Northwest regional director for the Crohn’s & Colitis Foundation, said her organization is excited by the clinical trial, “and even more excited for our patients at the chance for a cure.”
The Crohn’s Allogeneic Transplant Study’s investigation team also includes the University of Washington, Seattle Children’s and the Benaroya Research Institute.
If this trial is successful, McDonald said, he hopes to be able to broaden the criteria for others with Crohn’s.
“This is one step toward offering this as the definitive therapy for more patients with this disease.”