In a new clinical trial, researchers from Fred Hutchinson Cancer Research Center set out to test the theory that giving Crohn’s disease patients a new immune system can cure severe cases of the disease.
Crohn’s disease is a chronic inflammatory condition of the gastrointestinal tract with symptoms of pain, fever, diarrhea and weight loss, which usually occurs in adolescents and young adults, but which can also occur during early childhood and older age. The Crohn’s and Colitis Foundation of America estimates that more than 700,000 Americans are affected by the disease, although incident rates vary in different parts of the world, with incidence rates of 4 to 9 people per 100,000 in North America. 10% of Crohn’s disease sufferers are affected by the most severe form for which there is no completely effective treatment.
Researchers have made substantial progress in the medical treatment of Crohn’s disease over the past decade and a half, although even with the best immunosuppressive therapy, fewer than 50% of patients with a moderate to severe form of the disease achieve long-term relief. When Crohn’s patients cease taking their medicines, their intestinal inflammation returns and patients who took prolonged courses of medicines that suppress the immune system were noted to have some severe infections.
The initial aim of the Crohn’s Allogeneic Transplant Study (CATS) is to treat a small sample of patients with treatment-resistant Crohn’s disease by transplanting matched bone marrow cells from a sibling or unrelated donor, which replaces a diseased or abnormal immune system with a healthy one.
The researchers hypothesized that an exchange of the immune system may be successful based on evidence that Crohn’s is linked to abnormal immune responses to intestinal bacteria and to a loss of immune tolerance. CATS leading investigator George McDonald, M.D., a transplant researcher and gastroenterologist in the Hutchinson Center’s Clinical Research Division says that there is solid evidence that genetic abnormalities in the immune regulatory system are related to Crohn’s disease.
Even though the CATS clinical trial is a new direction for bone marrow transplantation, the procedure has already been used by Hutchinson Center researchers, who pioneered bone marrow and hematopoietic cell transplantation to treat blood cancers, and who have used allogeneic transplants to cure patients suffering from both leukemia and Crohn’s disease with the result that the signs and symptoms of Crohn’s disease subsequently disappeared. German studies have reported similar experiences.
Researchers have previously used autologous stem cell transplants in Crohn’s disease patients, whereby the patient’s own hematopoietic cells are removed and returned after high-dose chemotherapy to suppress the immune system. However, the benefits have only been partially permanent, which may be because the risk genes for Crohn’s are still in the patient’s body.
“Autologous transplantation following chemotherapy beats the disease down but the Crohn’s tends to come back The burden of this disease lays heavily on those who don’t respond to any therapy.”
For more information about CATS, please click here.
The website includes a patient-eligibility questionnaire. Patients must be aged between 18 to 60 years and have failed all existing conventional treatments yet they have to be sufficiently healthy to undergo a bone marrow transplant. Selected patients must either find a matched bone marrow donor from a sibling or an unrelated donor person who volunteers to donate their bone marrow. The patients must be covered by private insurance to cover the cost of the transplant and related medical expenses.
Written by Grace Rattue