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BY OUR PHARMA CORRESPONDENT 30
April,2007: Terminally ill patients with
incurable cancers are increasingly using a
compound via Internet trade that is not yet
approved, reports Nature.
The 'drug' in question -- dichloroacetate (DCA) –
has been but found shrinking tumours in rats but
yet to put on studies to ascertain its safety in
human use.
An experimental cancer drug shrinks tumours in
rats with no apparent side effects. While
researchers alert unanticipated side effects,
dying patients seems to think they don’t have the
luxury of waiting for years and years long
clinical trials to find out the safety of the
drug.
What’s DCA?
DCA is an odourless, colourless, inexpensive,
relatively non-toxic, small molecule. And
researchers at the University of Alberta believe
it may soon be used as an effective treatment for
many forms of cancer.
In January this year, Evangelos Michelakis at the
University of Alberta in Edmonton, Canada, and his
colleagues reported that DCA has seemingly
remarkable anticancer properties (S. Bonnet et al.
Cancer Cell 11, 37–51; 2007).
Dr Michelakis has shown that dichloroacetate (DCA)
causes regression in several cancers, including
lung, breast, and brain tumors.
Scientists and doctors have used DCA for decades
to treat children with inborn errors of metabolism
due to mitochondrial diseases. Mitochondria, the
energy producing units in cells, have been
connected with cancer since the 1930s, when
researchers first noticed that these organelles
dysfunction when cancer is present.
Until recently, researchers believed that
cancer-affected mitochondria are permanently
damaged and that this damage is the result, not
the cause, of the cancer. But Michelakis, a
cardiologist, questioned this belief and began
testing DCA, which activates a critical
mitochondrial enzyme, as a way to "revive"
cancer-affected mitochondria.
Michelakis and his colleagues found that DCA
normalized the mitochondrial function in many
cancers, showing that their function was actively
suppressed by the cancer but was not permanently
damaged by it.
More importantly, they found that the
normalization of mitochondrial function resulted
in a significant decrease in tumor growth both in
test tubes and in animal models. Also, they noted
that DCA, unlike most currently used
chemotherapies, did not have any effects on
normal, non-cancerous tissues.
"I think DCA can be selective for cancer because
it attacks a fundamental process in cancer
development that is unique to cancer cells,"
Michelakis said. "One of the really exciting
things about this compound is that it might be
able to treat many different forms of cancer”.
Another encouraging thing about DCA is that, being
so small, it is easily absorbed in the body, and,
after oral intake, it can reach areas in the body
that other drugs cannot, making it possible to
treat brain cancers, for example.
Also, because DCA has been used in both healthy
people and sick patients with mitochondrial
diseases, researchers already know that it is a
relatively non-toxic molecule that can be
immediately tested patients with cancer.
”The results are intriguing because they point to
the critical role that mitochondria play: they
impart a unique trait to cancer cells that can be
exploited for cancer therapy” Dario Alteri
Director University of Massachusetts Cancer Center
The DCA compound is not patented and not owned by
any pharmaceutical company, and, therefore, would
likely be an inexpensive drug to administer, says
Michelakis, the Canada Research Chair in Pulmonary
Hypertension and Director of the Pulmonary
Hypertension Program with Capital Health, one of
Canada’s largest health authorities.
However, as DCA is not patented, Michelakis is
concerned that it may be difficult to find funding
from private investors to test DCA in clinical
trials. He is grateful for the support he has
already received from publicly funded agencies,
such as the Canadian Institutes for Health
Research (CIHR), and he is hopeful such support
will continue and allow him to conduct clinical
trials of DCA on cancer patients.
On line trading of DCA
In the meantime Jim Tassano, who owns a
pest-control and marketing company in Sonora,
California, came across DCA when researching
alternative cancer therapies to help his dying
ballroom-dance instructor. He wanted something
that was effective, safe and that he could lay his
hands on: DCA fit the bill. He ordered some from
chemical supply companies, teamed up with a
chemist friend and they worked out a way to
synthesize the compound themselves. "I couldn't
walk away from it," Tassano says. "It could do so
much good for so many people."
Tassano set up two websites. The first of these (thedcasite.com)
hosts information on DCA and a patient chatroom.
On the second (buydca.com) Tassano is selling his
home-made DCA — labelled for veterinary use, as
drugs sold for human use in the United States must
have approval from the Food and Drug
Administration (FDA). Tassano says he is sure
patients are buying the drug to use on themselves,
and reckons that a couple of hundred of people
from around the world have bought from the site.
Many patients taking DCA — acquired from Tassano,
chemical companies or other sources — are
reporting their progress on thedcasite.com.
Some of these patients plan to set up a database
on Tassano's website to collect DCA results in a
more organized way. They want people to submit
information including the type of cancer they
suffer, medical history and the dose they are
taking, says Susan Hirasawa in Seattle,
Washington, who suffers from late-stage breast
cancer and is one of the organizers. The idea is
to provide information for others who want to take
DCA, she says, but "it's not a real clinical
trial".
Michelakis and other researchers are worried by
the development. Although DCA seems safe overall,
they point to a clinical trial that was stopped
early because those taking the drug developed
damage to their peripheral nerves (P. Kaufmann et
al. Neurology 66, 324–330; 2006). Without a
control group, they point out, it will be
impossible to tell whether any improvement in the
patients' condition is caused by the drug.
Patients could also be taking DCA that is not of
pharmaceutical grade and might contain harmful
impurities.
Michelakis says the patients could end up
undermining efforts to do a controlled clinical
trial if, for example, some develop harmful side
effects and the drug earns a bad reputation. "It's
destroying efforts to do this right," he says.
"Any way you look at this, it's a negative
development." An FDA spokesperson told Nature that
the agency is looking into the matter.
An estimated 95% of cancer drugs that enter
clinical trials do not get approval, many because
they are ineffective or unsafe, so patients risk
shortening their life or making their last days
more uncomfortable. "They say what do I have to
lose? The truth of the matter is, you have the
rest of your life to lose," says George Annas, an
expert in bioethics at Boston University School of
Public Health.
BY OUR PHARMA CORRESPONDENT |
