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Hope and fear: Part III

The promise of viral therapies

Continued from Page 2

"About half the patients have no side effects at all," Dr. Thompson said. "The most common side effects in the other half are mild fever . . . mild joint or muscle pain . . . and a bit of tiredness."

As well, a few patients in the trials who were not expected to live long are still alive, he said.

The U.S. National Cancer Institute is so intrigued by the company's strategy that earlier this year it announced it will pay for a multicentre clinical trial to test Oncolytics' stomach bug on patients with melanoma and ovarian cancer. "That's a big endorsement," Dr. Thompson said.

Dr. Bell is no longer involved with the Maryland company developing the Newcastle virus. With the Ottawa teams' hopes of genetically tweaking viruses to increase their ability to selectively target tumour cells, there was a parting of ways.

Said David Stojdl, who was once a postdoctoral student in Dr. Bell's lab: "We can engineer them to do whatever we want." Currently, he is working out ways to specifically arm viruses to break into tumour cells only, but still "trip the alarm" that will bring immune guards to protect healthy cells.

It's also possible, Dr. Bell said, that they could design a virus primed to attack cancer stem cells, which have recently been revealed as the engines driving several types of tumours.

But in the meantime, he sees a major challenge to the field: finding and keeping private-sector investment. Grants from government agencies such as Cancer Care Ontario help, he said. But academic grants are barely a sliver of what is needed to run clinical trials.

The Ottawa group has most recently been exploring a partnership with a California company to focus on vaccinia, a cowpox relation best known as an ingredient in the smallpox vaccine.

Dr. Bell understands that using live viruses as a medical treatment naturally raises concerns. In 1999, for example, Jesse Gelsinger, an 18-year-old American who suffered from a rare metabolic disorder, died after doctors injected him with a weakened cold virus as a means of delivering a corrective gene to his ailing liver.

"People are fearful, perhaps," Dr. Stojdl agreed, "that you don't have control of its distribution throughout the body."

Harold Atkins, a medical oncologist who has worked with Dr. Bell for eight years, also noted that the virus field doesn't follow the traditional course of other therapies.

"With chemical drugs," Dr. Atkins said, "there's 40 to 50 years of understanding how drugs interact with the body and find their target, and with this, it's not clear those lessons apply."

Still, the Ottawa group is forging ahead. In a tower that overlooks the cancer centre, a small, stark white biofactory of negative air-pressure rooms is under construction where the researchers hope to produce their cancer-fighting viruses for clinical trials.

"Our purpose here," Dr. Bell said, "is to get it far enough along so that it's not viewed as a fringe concept."

From the vantage point of a private-sector player, Dr. Thompson is more optimistic. The drug industry may have been initially reluctant, he agreed, because of safety concerns. But safety trials have gone well.

"[Pharmaceutical companies] have never really lost interest. They've always been watching over our shoulders."

Industry's main concerns, he said, are, "Can you produce enough and will it work well?"

Viruses like the common cold and stomach bug may be ubiquitous in nature, but producing enough of them for use in treatment is a challenge.

Dr. Thompson explained that 10 trillion viral particles are needed for one IV treatment, and a patient may receive as many as 45 treatments over a nine-month period.

After a six-year investigation, Oncolytics has turned to a European manufacturer to grow Reolysin in human cell lines, where the virus can replicate itself and then be harvested.

Dr. Thompson suspects the interest from big companies will follow from the next phase of trials, which he said is preferable as an initial investor: "You are rewarded for the risk you undertake."

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Series schedule

Nov. 20 Drugs and dollars:

The pressure of high costs on care

Nov. 21 So tired of waiting:

Treatment is still taking too long

Nov. 22 Canada's research chasm: A nation falls behind

Nov. 23 PET scan scandal: High tech sits idle

Nov. 24 Screen test: Beating the

colorectal killer

Nov. 25 in Focus English lessons: The quest for a national strategy

Nov. 25 in NewsThe science of stem cells: A new way of looking

at cancer

Nov. 28 The end of chemo: There must be a better way

Today Can a shot of the flu cure cancer?

Saturday In his shoes:

Eight-year-old Spencer fights to live

Wednesday, Dec. 6 It's everywhere: Is the environment killing people?

Saturday, Dec. 9 "C-type" mentality: The psychology of survival

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