Skip to main content

Italian doctor Paolo Zamboni in his studio at the University Hospital of Ferrara. He believes MS is caused by venous abnormalities, a theory that has been seized by thousands of patients across Canada who have flown to expensive overseas clinics for treatment of blocked veins.Alessandro Vincenzi for The Globe and Mail

In stark contrast to Canada's go-slow approach, U.S. drug regulators have issued their strongest warning yet to multiple sclerosis patients about the dangers of a controversial new treatment.

The Food and Drug Administration issued its alert on Thursday after it received adverse reports connected with two patients who had the experimental therapy in the United States: One died from bleeding in the brain and another was paralyzed from a stroke. The agency said it also has heard reports of stents (sometimes used in the procedure) migrating to the heart, cranial nerve damage, blood clots and abdominal bleeding related to the procedure.

The frequency of these complications is unknown.

"Because there is no reliable evidence from controlled clinical trials that this procedure is effective in treating MS, FDA encourages rigorously conducted, properly targeted research to evaluate the relationship between [the therapy]and MS," said William Maisel, chief scientist and deputy director for science in the FDA's Center for Devices and Radiological Health. "Patients are encouraged to discuss the potential risks and benefits of this procedure with a neurologist or other physician who is familiar with MS and [the procedure]"

The so-called liberation therapy is based on an unproven hypothesis advanced by Italian doctor Paolo Zamboni that some cases of MS are not an autoimmune disease but vascular disorders caused by vein blockages that lead to a buildup of iron in the brain, and can be treated by a simple surgical procedure – angioplasty.

The FDA warned patients of the risks of serious injuries and death, emphasizing that studies exploring the link between MS and vein blockages are "inconclusive." It also told doctors and researchers that any studies using medical devices, such as inserting stents in the veins, must be approved by U.S. regulators. One trial was voluntary shut down because the researcher did not have approval.

Ottawa has repeatedly cautioned people considering the procedure, but has made no formal declaration to warn MS patients.

Unlike in Canada, the procedure is readily available in the United States. That hasn't stopped thousands of Canadians from travelling as far as Costa Rica, Poland and Kuwait to have the treatment at private medical clinics, which typically costs thousands of dollars. At least two Canadians have died after having the therapy.

The federal government recently announced plans to accept research proposals for a small study. Health Minister Leona Aglukkaq said the "limited clinical trial" would need ethical approvals from medical authorities before getting the green light.

"When it comes to clinical issues, I rely on advice from doctors and scientists who are continually monitoring the latest research, and make recommendations in the best interests of patient health and safety," Ms. Aglukkaq said.

Several provinces with particularly high rates of MS, such as Saskatchewan and Newfoundland and Labrador, have committed millions toward clinical trials to study the vein-widening treatment.

Anthony Traboulsee, director of the University of British Columbia Hospital MS Clinic, who is also conducting a study, said the FDA message is not far from what the Canadian medical community and politicians have been saying. "The main difference," he said, "is that Canadian professionals and government agencies have stated the need for high-quality research on this topic."