Is Gordie Howe's stem cell recovery the 'miracle' it's cracked up to be?

Canadian experts in stem cell research are warning that Gordie Howe's heralded recovery from multiple strokes after an experimental stem cell treatment is a rarity and that there is the possibility of complications from the treatment. The son of Canadian hockey legend Gordie Howe called his father's recent recovery, "nothing short of a miracle" at an event in Calgary this week. Marty Howe said his father is walking, beginning to speak and is able to play with his grandchildren after he took part in a clinical trial in Mexico that saw stem cells injected into his spinal canal and his bloodstream.

"You usually hear about the rare cases and they always seem to be immediately after the transplant," Dr. Mick Bhatia, told CBC Radio's Brent Bambury. "Follow up, however, and subsequent indication that the positive effects have been sustained are extremely rare. I personally am unaware of anyone that's gone back and reported a sustained effect," said Bhatia who is director and senior scientist at McMaster University's Stem Cell and Cancer Research Institute. 

Howe's family approved his participation in the clinical trial in Tijuana, Mexico following discussions with medical representatives of Stemedica, the U.S. company providing the stem cells for the trial. Another company, Novastem, is conducting the trial at their Clinica Santa Clarita facility.

Dave McGuigan, vice president of marketing and business development for Stemedica and Howe family friend, contacted the family about the possibility of taking part in the trial after he heard of Howe's strokes last year.

Stemedica has been involved in clinical trials in the United States, but the treatment tested on Gordie Howe is not currently approved by Health Canada or the U.S. Food and Drug Administration. According to McGuigan, the main difference between the U.S. and Mexican trials is that in the U.S. people are only eligible for the experimental therapy six months after having a stroke. In Mexico, Stemedica has government approval to proceed with clinical trials within two weeks of a patient having a stroke.

"When the Howe family evaluated the protocol for both clinical trials, they didn't believe that Gordie could live as long as six months, so they decided to enrol him in the government-sanctioned clinical trial in Mexico," says McGuigan.

But Bhatia says Howe's case presents more questions than answers.

"What is the origin of those cells? Why are they classifying them as stem cells? Were there multiple injections? Were the patients given some sort of drug before they were injected, or after, or during? A lot of questions," says Bhatia. "But that's sort of par for the course for these stem cell transplants that are outside of North America or some of the centres in Europe."

Dr. Lev Verkh, chief regulatory and clinical officer for Stemedica told the Canadian Press that his company's products - bone marrow-derived mesenchymal stem cells from young healthy donors and neural stem cells derived from donated brain tissue - don't trigger the immune system, so patients don't need medications, including immunosuppressant drugs.

Bhatia disputes that claim. "Scientifically, I'd like to know what the evidence is. All cells in people's bodies can identify something that is their own versus something that's foreign," says Bhatia. "That's how the immune system combats bacteria or viruses as well. So if these cells that are being put in are not being detected by the patient's immune system, that's very interesting and I think some evidence behind that, especially something so paradigm-shifting, is probably required."

The other explanation, says Bhatia, is that the injected cells don't trigger an immune response because they die shortly after entering the body.

He also warns that stem cell injection can be far from innocuous. Beyond the risk of major financial cost of experimental treatments, the biggest risk comes from the fact that stem cells are programmed to regenerate and grow. 

"You can imagine if these cells land in the wrong place after injection," says Bhatia. "These cells can go anywhere. And if they're in the incorrect place, they may grow uncontrollably, and that's something you would call a tumour."

Not only that, says Bhatia, but they might also grow in places that affect the healthy tissue in unpredictable ways. "It's not like a drug, where a chemical may have an adverse effect and you can simply stop taking the drug. When you inject a cell, that cell, if it goes rogue in the body, will continue and there's no way of controlling it."

McGuigan, however, says that what Stemedica does is different from unregulated treatments and clinical trials going on around the world in places like China, Poland and Mexico. "We know from our U.S. trial that we've seen incremental improvement in functional, physical and cognitive skills," he says.

"We know that our cells have been deemed safe by an independent data monitoring board. So based on that and other evidence we've seen from other clinical trials we feel that the stem cells have played some role in the recovery process," says McGuigan. In an emailed statement, McGuigan added that Stemedica has carried out two clinical trials and there have been no adverse patient reactions.  

It may be inevitable that Gordie Howe's high profile and his recovery from near-death will encourage others to pursue similar stem cell treatments. "That's certainly the concern. I think anyone as iconic as Mr. Howe and other celebrities that participate in these types of things definitely send a message to everyone," says Bhatia. 

"I would caution anyone trying to think about these types of transplants to ask common sense questions like you would from your doctor or any hospital in North America. If the comfort level isn't there, I would really worry about the risk, both in loss of money and potential danger of being transplanted with cells that are uncontrolled, you don't know what they are, what that can do in the long run."