Thursday April 28, 2016

Canadian researcher says immunotherapy is a cancer-fighting miracle

From left, Sean Parker and Jeffery Bluestone at the Parker Institute for Cancer Immunotherapy Scientific Retreat in St. Helena, Calif. A project to speed development of cancer-fighting drugs that harness the immune system.

From left, Sean Parker and Jeffery Bluestone at the Parker Institute for Cancer Immunotherapy Scientific Retreat in St. Helena, Calif. A project to speed development of cancer-fighting drugs that harness the immune system. (Nano Visser/Parker Institute/Associated Press)

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When Alan Taylor, a 46-year-old father of two from Toronto, decided to have a dermatologist remove a lesion from his leg, he didn't expect the phone call telling him it was melanoma, or the implications of the diagnosis. 

"The thing that shocked me," he tells Day 6, "was that he told me I should go out and get a will done, which was pretty terrifying. It almost made me seem like I was done right from the very beginning." 

It was an aggressive cancer. About a year after the surgery, tumours were spreading throughout his body, his lungs and his brain. Doctors told him there was only one option left, and it would probably just slow the advancement of his disease.

"Instead," says Taylor, "this drug turned out to be the miracle drug for me." 

The drug Taylor is taking, PD 1, is from a class of medications called immunotherapy. They help the body fight cancer by using its own immune system and oncologists are finding them effective against a growing list of cancers. 

Former U.S. President Jimmy Carter, who announced last summer his malignant melanoma had spread to his liver and brain, now believes he is cancer-free because of PD1 and immunotherapy.

Last week, at the American Association for Cancer Research in New Orleans, evidence was presented showing immunotherapy has been successful in treating a resistant and lethal carcinoma, suggesting a new course for treating virus-caused cancers. 

"This is the way of the future for cancer therapy," Dr. Pam Ohashi, the director of the immune therapy program at the Princess Margaret Cancer Centre in Toronto, tells host Brent Bambury. "It's really a game changer." 

Dr. Ohashi has been a researcher in the field of immunotherapy for 20 years. She says the latest findings are both exciting and a vindication.  

"I think it's really fantastic. It's almost exhilarating because the few of us who are diehards in this field of immunotherapy have just been waiting for this moment to hear such success stories."

 "It's like Viagra for the immune system" - Dr. Pam Ohashi on the promise of immunotherapy in treating cancer

How immunotherapy works

The human immune system is effective in identifying viruses and infections, but not tumours or cancers. 

"A cancer is a little different than a virus because it's part of your body," explains Dr. Ohashi. "The immune system doesn't want to get too out of control so it has checks and balances. So it may start to attack the cancer but over time all these other barriers get thrown up against this natural attack on the tumour. So what you want to do is shut off the stop signals and that's what PD 1 does. The analogy I like to use for PD 1 is that it's like Viagra for the immune system."

Because it is still an experimental treatment, immunotherapy is only used on patients who are not responding to established treatments. 

"That means a patient normally undergoes some kind of chemotherapy, some kind of radiation therapy and then they find they have no other options so then we start the immunotherapy," Dr. Ohashi tells Bambury. 

Dr. Ohashi believes the new evidence presented in New Orleans shows clinicians may be soon be able to introduce the treatment as something other than the final option. 

"In terms of the vision of the next few years we have to ask the question: Is it better to actually use immunotherapy early on the patient treatment? Right now we have no options for that." 

Immunotherapy does not work for everyone. Future research will investigate the role genetic mutations play in the effectiveness of the therapy, but Dr. Ohashi says it's already saving lives and changing oncology. 

"Ten years from now I can say for sure there are going to be people on this earth that should not have been here if there was not immunotherapy." 

That's true of Alan Taylor and his doctors agree. 

"I've had some of the doctors tell me that it's a miracle that I'm still around today."

Dr. Ohashi says she's fine with using the phrase 'miracle drug'.

"I think it's absolutely true. I think the whole field realizes this is a miracle drug. You see the enthusiasm from the pharmaceutical industry; when we first started this approach there were two different pharmaceutical companies developing these drugs. Now there are over 12. They realize this is a blockbuster drug."