At the height of last summer's national debate over the multiple sclerosis "liberation therapy," Manitoba Health Minister Theresa Oswald was being briefed weekly, suggesting the controversial treatment was top-of-mind for the minister.

But the province won't reveal details of the internal debate that prompted Oswald to hold off on clinical trials in Manitoba.

But the province won't reveal details of the internal debate that prompted Oswald to hold off on clinical trials in Manitoba.

More than half the information in the briefing notes is censored -- in some instances, up to 90 per cent on each page. Still shrouded in secrecy is the government's internal analysis of the issue, including recommendations and cautions from Manitoba's senior health experts.

In an interview, Oswald said she heard from vascular surgeons, doctors from the MS Clinic in Winnipeg, researchers and her own staff, many of whom cautioned her against launching isolated clinical trials too early.

"There's no question I began my journey by saying 'Let's just start clinical trials right now,' " said Oswald. "But it became really clear if what I wanted to do is cross the finish line with an answer, one of the worst things we could do as a nation is go off in different directions doing a patchwork of trials."

Oswald said she got opinions on both sides of the debate, including from MS sufferers and advocacy groups, but she wouldn't name names. She said doctors and health staff must be free to give her frank advice knowing their submissions will remain confidential. She said the issue is so emotionally charged, some doctors have even been threatened in other jurisdictions.

In September, a freedom of information request revealed that from late 2009 to mid-2010, Oswald was given 14 briefing notes on the vein treatment widely known as liberation therapy. Six were delivered to her between June 15 and July 23, shortly after the first MS Liberation Day rally was held at the Manitoba legislature and a week before Oswald announced on July 29 the province would not perform its own clinical trials of liberation therapy.

Saskatchewan has offered to fund clinical trials within its province, and Newfoundland and Labrador is launching its own "observational studies."

Manitoba has called for co-ordinated, pan-Canadian trials and is willing to chip in $500,000, but Ottawa has said it will not fund trials of a therapy many doctors call unproven and dangerous.

Oswald said she was "like a dog with a bone" at a recent meeting of health ministers who agreed, some reluctantly, to co-operate on clinical trials, if and when they get the scientific go-ahead. They are awaiting the results -- expected in a matter of months -- of seven diagnostic studies that are expected to help their decision on whether to proceed.