OTTAWA - The federal government will fund a clinical trial of a controversial treatment for multiple sclerosis patients but it could be years before so-called liberation therapy is widely available in Canada.

Health Minister Leona Aglukkaq announced the move Wednesday in spite of recent studies that have cast doubt on narrowed neck veins as the primary cause of the debilitating illness.

She said a scientific working group established by the federal government last August has agreed unanimously that a preliminary clinical trial into a controversial vein-widening procedure should proceed.

"Our government has been clear that we were prepared to fund a clinical trial, but only when there was sufficient medical scientific information to support proceeding safely," said Aglukkaq.

She said the team, sponsored by the Canadian Institutes of Health Research, reviewed scientific reports on the procedure and deemed it safe enough to go ahead.

"There is unanimous agreement that a clinical trial should proceed at the Phase 1 and Phase 2 level."

Aglukkaq attached no dollar figure on the federal funding. She said that will depend on the proposal that's ultimately accepted by the CIHR for conducting clinical tests on liberation therapy.

Narrowed neck veins -- or chronic cerebrospinal venous insufficiency -- became the subject of numerous studies after Dr. Paolo Zamboni of Italy theorized it could be a factor in the development of MS.

Zamboni surmised that reduced blood flow leaves iron deposits in the brain, leading to the neural lesions typical of MS. He contends that reversing the condition by unblocking neck veins using balloon angioplasty could help alleviate symptoms.

Many hopeful Canadian MS patients have gone abroad seeking the procedure, which isn't offered in this country, while the MS community has been leaning on Ottawa to proceed with trials.

In the absence of action from Ottawa, Saskatchewan and Manitoba have committed funding for clinical trials. Earlier this month, New Brunswick announced it will provide public funding to help cover the costs of receiving liberation therapy abroad.

Some clinical studies -- most recently by a team at the University of Buffalo -- have indicated that the vascular condition does not have a primary role in causing MS and have cast doubt on the efficacy of liberation therapy.

But CIHR president Dr. Alain Beaudet said the evidence reviewed so far suggests "a trend to an association between the greater prevalence" of blocked neck veins in patients with MS than in healthy people.

"More studies will be needed, and particularly the results of the seven ongoing studies will be needed, to strengthen this conclusion. But, nonetheless, the committee felt that, on the basis of this preliminary evidence and what's published so far, that we should in parallel start already with a Phase 1-2 trial."

Beaudet said it's hoped the preliminary trials , which involve only small sample groups, will begin early in 2012. Realistically, he said it will be at least a year before any results are known.

Should preliminary results warrant, a phase 3 trial, involving hundreds of patients, would then be undertaken. Beaudet conceded it could take years before determining whether liberation therapy works and should be widely available in Canada.

"Clinical research takes time but you don't want to subject patients to a treatment that has not been proven and you don't want to carry out a trial on patients without having the necessary scientific evidence to do so," he said.

"I believe that we are proceeding in the way that science tells us we should be proceeding."

The MS Society of Canada, which has committed $1 million toward the cost of a clinical trial and has been lobbying hard for federal funding, welcomed Aglukkaq's announcement.

"We are pleased to see that the federal government and CIHR have kept MS at the top of their health care agendas," the society said in a written statement.

Opposition parties also welcomed the announcement but criticized the federal government for taking so long and expressed concern about how long the trials will now take.

"I think there'll be continuing, very strong pressure on the government to move as quickly as possible," said New Democrat MP Libby Davies.

"It's going to come from us politically but it's also going to come from the (MS) community because this is now a well-organized community and I think they do have legitimate expectations that they want the government to act with the greatest speed and efficiency to get this under way."

Liberal MP Kirsty Duncan said Canadians with MS have been calling for clinical trials since November 2009 when news of liberation therapy first emerged. Fifty other countries have already launched clinical trials.

With some 55,000 to 75,000 Canadians afflicted with multiple sclerosis and 400 a year dying from the illness, Duncan said: "If (liberation therapy) improves quality of life, it's incumbent on us to do the science and do it as quickly as possible."

Duncan has been keeping close contact with 300 Canadians who've undergone the vein-widening procedure and she said there've been "some very exciting results." She knows of wheelchair-bound patients who've been able to walk again and home-bound patients who've been able to return to work.

Aglukkaq maintained the government has acted swiftly but prudently.

"What we've been able to accomplish since the time the issue was raised and today has been significant," she said, adding that she's asked Beaudet to move as quickly as possible on launching the trials.

"We agreed to move forward with clinical trials once the evidence was there ... The evidence is now here."