Researchers at the University of Alberta have been flooded with calls from people volunteering to take part in human trials for a cancer drug that significantly shrunk tumours in rats.

Health Canada has approved dichloroacetate, or DCA, for a limited trial on people with an aggressive brain cancer called glioblastoma. Researchers are looking for 50 patients in Edmonton who have already tried chemotherapy, surgery or radiation with no success.

The university has already received 100 phone calls from potential volunteers.

Known as "The Terminator," the cancer has an average survival rate of one year with conventional therapy, said Dr. Kenn Petruk, head of neurosurgery at the university.

The drug, to be tested over the next 18 months, has already showed it can shrink lung, breast and brain tumours in animal and human tissue experiments. Lead investigator Dr. Evangelos Michelakis said doctors will know early into the trial whether DCA is having any effect.

"In six weeks or so, we will know if the drug will have some efficacy on the tumour," Michelakis said at a news conference Wednesday. "But that doesn't mean that the job is done. We still have to show that the tumour didn't increase or, even better, decreased."

Researchers said DCA cuts tumours off from the glucose they feed on. Without it, cancerous cells die off.

The team will monitor how much glucose the tumours are taking in during the treatments and then watch to see whether they stop growing or even shrink.

No debilitating side-effects expected

DCA does not appear to harm normal cells, which means there would be none of the debilitating side-effects such as nausea and extreme fatigue associated with conventional cancer therapies.

No pharmaceutical companies are involved in the trial, which Michelakis said is because DCA is cheap and can't be patented. Researchers around the world have raised $800,000 in grants and donations to fund the clinical trial.

But Michelakis emphasized that DCA is not a miracle cure.

"Oncology is full of examples of miracle drugs in animals that never make it because they don't work in human beings," he said.

"That's why I want to emphasize of equal importance to this drug itself is the fact that such an effort is taking place and it should inspire other places to develop generic drugs without the support of the industry."

Don't self-medicate, cancer society warns

DCA is already used to treat lactic acid buildup in children as well as patients with diabetes and AIDS.

In March, reports of cancer patients trying to self-medicate with DCA prompted the Canadian Cancer Society to warn people not to use it until it has been fully tested on humans.

Michelakis said it will be six months or more before any results of the clinical trial will be made public.

With files from the Canadian Press