WEDNESDAY, July 18 (HealthDay News) — When common heart drugs
such as digitalis and digoxin are combined with some chemotherapy drugs,
the effect appears to be an increase in the death of cancer cells,
according to French researchers.
These medications, called glycosides, have been around for decades and
are used to treat heart failure and irregular heartbeats.
When combined with chemotherapy drugs, however, they appear to act
similar to a vaccine — priming the immune system to kill cancer
cells.
“This is very exciting; it describes a new way to make chemotherapy
more effective,” said Marc Symons, an investigator at the Center for
Oncology and Cell Biology at the Feinstein Institute for Medical Research
in Manhasset, N.Y. Symons was not involved in the study, which was
published July 18 in the journal Science Translational Medicine.
The effect was first noticed when the French team, led by Laurie Menger
from INSERM in Villejuif, combed through patients’ medical records. They
discovered that cancer patients undergoing chemotherapy who were also
taking these drugs for heart trouble tended to do better than cancer
patients who did not take them.
The authors said this appears to be because the drugs convert dead
cancer cells into a kind of trigger that alerts the immune system to
attack tumor cells.
This approach to cancer therapy still needs to be tested, however, and
the researchers said they plan to do so in patients with neck and head
cancer.
William Chambers, director of Clinical Cancer Research and Immunology
at the American Cancer Society, noted that the researchers also have
developed a way of screening drugs to see if they will have this effect on
cancer cells. That could help spot drugs that trigger an immune response,
he said.
“It also reinforces the notion that the immune system and chemotherapy
working in concert is really going to be important for effective
treatments for cancer,” he said. “Immunotherapy for cancer has been a
‘sweet spot’ in the last couple of years. A lot has been happening there.”
“We have learned a lot about the immune response to cancer,” he added.
“There is a lot of potential here and I expect we are going to see a good
bit more looking at this phenomenon.”
One of the unanswered questions is what the effect will be of using
these heart drugs on cancer patients with healthy hearts.
“Digoxin and similar drugs have effects on the heart that could be side
effects in patients with normal hearts,” said Dr. Kirk Garratt, director
of interventional cardiovascular research at Lenox Hill Hospital in New
York City.
These effects could pose a problem for these patients, he said, “but
right now I don’t see this as a problem in pursuing this research.”
Garratt cautioned chemotherapy patients that not enough is known to add
these drugs to their treatment at this point in time.
“It’s too early to take that action,” he said. “We don’t know what
side-effect issues might surface. We don’t know what the downside will be,
and there is always a downside.”
For heart patients, however, these drugs are very safe, Garratt said.
And there’s another up side, he added: Since these drugs have been around
for years, they are generic and inexpensive.
Although the study revealed an association between the use of these
heart drugs and an increase in the death of cancer cells, it did not prove
a cause-and-effect relationship.
More information
To learn more about cancer immunotherapies, visit the American Cancer Society.
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