As
desperation leads patients to experimental treatments overseas, a leading
neurosurgeon says it’s time.
Before his accident, Mike Kowalski loved fast
motorcycles. At 26, he rode his bike from his home in Markham, Ont., three
hours north to Haliburton—it has “nice roads and less cops,” he says—when he
took a turn too fast. Hitting a gravel patch, Kowalski lost control. His first
and only motorcycle crash left him paralyzed from the chest down. Devastated,
he tried to be optimistic: rapid advances in stem cells seemed to suggest
powerful new treatments on the horizon. “I was mentally prepared for five
years,” Kowalski says. “Not to be back where I was, but that I’d be using a
cane instead of a wheelchair.”
Kowalski kept up with the latest research,
attending conferences and chatting with scientists about their work in stem
cells. As time went by, and treatments failed to materialize in North America,
he got increasingly frustrated. Two years after his accident, he went to
Taiwan, where an experimental “nerve cocktail” was injected into his spine.
Five years later, he went to Beijing and received an embryonic stem cell
transplant. Neither treatment, which cost about $20,000 each, made much of a
difference, he says. He kept waiting. “Five years came and went, and then 10.”
It’s now been 11 years, and Kowalski still uses a wheelchair. “It seems
incomprehensible that we can fix rats in a lab and fly rovers to Mars,” he
says, “but we can’t regenerate some nerves in my spine.”
Stem cells, which can grow into any cell type
in the body, have been touted as a potential cure for everything from type 1
diabetes to stroke. They aren’t without controversy—embryonic stem cells come
from discarded human embryos—but they hold huge promise, too. This is certainly
true when it comes to spinal cord injury, a devastating condition that affects
about 86,000 Canadians. Unlike muscles, organs, skin and blood, the central
nervous system can’t repair itself; despite huge advances in treatment and
rehabilitation for this type of injury, the damage is often permanent. In
theory, stem cells could be injected into a damaged spinal cord to promote repair.
Now one influential Toronto neurosurgeon says it’s time to take stem cells out
of the lab and into the clinic.
Dr. Michael Fehlings, medical director of the
Krembil Neuroscience Centre at Toronto Western Hospital, makes his case in the
October issue of Neurotherapeutics. Cell therapies shouldn’t be “stalled at the
animal model stage,” he writes. No rat, pig or monkey can perfectly mimic the
human condition; after years of working on these animals in the lab, we should
pursue “focused, safe and ethical” trials in humans. All new therapies carry
their risks. Stem cells “can make anything, but that’s also the danger,” he
told Maclean’s in an interview. If they were to grow out of control, these
cells could potentially turn into cancer. One argument for moving forward is to
stop patients like Kowalski from making desperate trips overseas. “I’m not in
favour of medical tourism,” Fehlings says. If patients receive stem cell
treatments, “it should be in a carefully regulated clinical trial, with fully
informed consent, and they shouldn’t be charged.” After all, we still don’t
know if these treatments will work. “We’re hopeful,” Fehlings says, “but
there’s a difference.”
A small number of trials have already begun,
Fehlings points out, but they’ve faced “incredible hurdles” in getting
approved. Geron, the California company now conducting the first human clinical
trial of an embryonic stem cell-based therapy, had to submit a 21,000-page
application to the U.S. Food and Drug Administration (FDA) outlining 24 different
animal studies before it got the green light. Using stem cells derived from
human embryos that were discarded after fertility treatments, Geron’s technique
transforms stem cells into crude versions of nerve cells, which are injected
into the spinal cord. It showed good results in lab rats, who regained some
function. Geron’s phase one clinical trial was launched last year; four
patients have received transplants, with no adverse effects from the cells or
surgery reported so far.
In Canada, there have been no human stem cell
trials, in part because government regulations are quite strict. “If anything,
the bars here are even tougher,” Fehlings says. “The science has moved at a
rapid pace. It’s a very daunting task for regulators to stay up to speed.”
Freda Miller, another star Toronto researcher, believes there’s good reason to
be cautious. “A lot of us are nervous about those trials,” says Miller, a
senior scientist at the Hospital for Sick Children Research Institute and a
University of Toronto professor. Any stray embryonic stem cells left over in
the cell preparation could be a danger, she says. “It would be a death knell
for stem cell-based therapy if an ill-conceived trial led to a patient having a
tumour in the spinal cord.”
Beyond that, scientists debate whether lab
rats tell us enough about spinal cord injury to safely attempt these treatments
in humans. In his paper, Fehlings calls it an “unrealistic hurdle” to expect
researchers to validate all their findings in bigger animals, like pigs and
monkeys, before launching a clinical trial. “If every treatment had to be
replicated in monkeys, we would never move forward,” he says. But Miller points
out that a lab rat isn’t the ideal stand-in for a person with an injured spinal
cord. “The size of a lesion in a rat is very different, and their spinal cord
is somewhat different,” she says. “Even if you injure them badly, they can get
some hind leg locomotion back, which is not the case for humans. You can’t
predict what would happen in humans on the basis of a rat.”
Miller is concentrating on Schwann cells, a
type of cell not found in the brain or spinal cord that helps peripheral nerves
to function and heal. Several years ago, McGill University’s Albert Aguayo
showed that transplanting Schwann cells into the central nervous system could
help it regenerate; in 2007, Miller found a way to derive stem cells from a
patient’s skin and then generate Schwann cells. Today, her lab makes Schwann
cells in Toronto, then flies them to Vancouver, where they’re transplanted into
lab animals for study. She and her team are “laying the groundwork” for a
clinical trial in Canada, she says, which she hopes to begin in the
“not-too-distant future.”
Using a patient’s own cells to treat their
injury, instead of donor cells, could be ideal. Doctors wouldn’t have to worry
about rejection, Miller says, and there would be no ethical conundrum. A team
at the Miami Project to Cure Paralysis, based at the University of Miami, is
awaiting FDA approval for another trial involving Schwann cells, and hopes to
start enrolling patients in late 2012. They’ve developed a way to harvest a
patient’s mature cells from a nerve in their leg, grow a lot more of them in the
lab, and then transplant them into their injured spinal cord to promote
healing. This technique doesn’t require stem cells, although they could
theoretically help. “If you could take a skin sample and then make different
kinds of cells, that would probably be much more user-friendly,” says Kim
Anderson-Erisman, director of education. “There’d be no need for a biopsy.”
Despite the urgency of scientists in the lab,
it isn’t clear how many patients with spinal cord injuries would actually opt
for stem cell treatments, even if they were available, which is highlighted in
a 2011 study co-authored by Judy Illes, a neuroethicist at the University of
British Columbia, who interviewed individuals with spinal cord injury about
their experiences. People tend to think all patients are fixated on walking,
but this study noted that it isn’t necessarily the main goal. Depending on the
type of injury, they could view regaining the use of their arms and hands,
improved bladder and bowel control, or sexual function as their highest
priority. And as the study points out, patients’ views can shift over time. The
longer they adapt to living with their injuries, the less likely they seem to
be inclined to enrol in a clinical trial, which might uproot them again. One
said, “The transition was hard enough the first time; I don’t want to go
through it again.”
Of the few existing clinical trials, including
Geron’s, most recruit patients “at very acute time points,” a week or two after
the injury, Illes notes. “We would never say, ‘Stop the science,’ ” but the
goal is to determine the best ways to make sure patients give well-informed
consent and “do not make one-time, sudden decisions at a time of tremendous
life change and desperation.”
It will realistically be decades before most
patients can benefit from stem cell treatments. In the meantime, better
surgery, drugs and rehabilitation have dramatically improved outcomes. “In the
past, people with severe injuries didn’t tend to live very long,” says Dr.
Anthony Burns, medical director of the spinal cord program at the Toronto
Rehabilitation Institute, the largest of its kind in Canada. “That’s changed a
lot. With diligent and appropriate care, their lifespans are approaching those
of able-bodied individuals.”
The benefits were clear on a recent morning in
late October at the Toronto Rehab facility, where Gord Sloan, a 54-year-old
farm owner from Schomberg, Ont., exercised on a treadmill. Wearing a harness,
he took careful steps while physiotherapist Trish Stapleford braced him. Sloan had
surgery on Sept. 5 to remove a benign tumour from his spine, and he came to the
centre as an in-patient shortly after. At the time, he was “flat on his back,”
he says. Sloan has been working closely with Stapleford and on his own,
spending hours at a stretch in the gym. That day, as she helped him take
halting steps backwards, he said, “it’s a long way from early September.”
Sloan’s discharge date is Nov. 11, and he hopes to walk with a cane.
Kowalski has adjusted to living with his
injury, too. Just over a year before the motorcycle accident, he got married.
“We stayed together,” he says. “Many don’t.” Three years later, they had twins,
a boy and a girl. He’s stopped following the latest research as closely as he
once did. “It’s painful to live and breathe it like I used to do, and not see
it come to fruition,” he says. “I backed off, and focused on my kids and work.
You can choose to be miserable, or choose to be happy.” Even so, Kowalski
admits he’d seek out another experimental treatment overseas if one became
available. “I want my life back,” he says, “or as close to it as possible.”
Kate Lunau
Business & Investment Opportunities
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