Diabetes pill from 1958 shows promise as new cancer drug

Updated 10/8/2012 3:56 PM

The next new treatment for breast, colon and prostate cancers, among others, may be a diabetes drug first approved in 1958.

Metformin, the most commonly used medicine to lower blood- sugar, is the subject of about 50 cancer studies globally, according to U.S. government clinical trial information compiled by Bloomberg. The research began after scientists found metformin prevented tumors in mice and that diabetics were less likely to develop a malignancy if they were taking the 5 cents- a-day pill than other diabetes medications.

The medicine is dispensed about 120 million times annually, according to a 2010 report in the journal Molecular Cancer Therapeutics. If the latest trials on breast and other tumors are successful, the drug could become a cheap weapon in the fight against a myriad diseases including pancreatic and ovarian cancers. All told, cancer kills one in eight people and is the second-leading cause of death in most developed countries.

"The hope is that if it does show safety and efficacy, it would be available in a cost-effective way," said Chandini Portteus, vice president of research, evaluation and scientific programs at Susan G. Komen for the Cure, a Dallas-based breast cancer advocacy group. "It would be wonderful for patients if we had something that we knew worked and was safe and low- cost."

The organization has spent about $10 million investigating metformin for breast cancer, Portteus said. "We have to turn over every single rock to determine what the options are for patients who need them."

Global cancer deaths will climb to 13.1 million by 2030 from 7.6 million in 2008, the Geneva-based World Health Organization said in February. Cancer costs totaled $124.6 billion in the U.S. alone in 2010, according to the National Cancer Institute. Newer, more targeted drug therapies, such as Dendreon Corp.'s $93,000-a-year Provenge for prostate cancer, may add only a few months of life.

Metformin was the seventh most-dispensed medicine in the U.S. in 2011, according to a list published by IMS Institute for Healthcare Informatics in April that ranked a group of painkillers that includes Vicodin as the most-prescribed. A pack of 84 500-milligram tablets of the diabetes pill, taken twice daily, costs the U.K.'s National Health Service 1.37 pounds, or the equivalent of about 5 U.S. cents a day.

The MD Anderson Cancer Center in Houston is studying metformin in at least eight trials, according to a National Institutes of Health online database.

"It is safe and it is cheap," said Donghui Li, an epidemiologist and professor of medicine at the center. "It reduces the risk and has better survival" in studies she's done in pancreatic cancer patients.

Patients who had taken metformin had a 60 percent lower risk of developing pancreatic cancer, according to a case- control study Li published in 2009 in which she compared cancer patients taking metformin against people not on metformin.

Metformin didn't benefit patients whose pancreatic cancer had already spread to other tissues, Li reported this year in the journal Clinical Cancer Research. Those patients whose malignancies were confined to the pancreas survived longer if they were on metformin -- an average of 15 months, or four months more than patients not taking the drug, she found.

More research is needed to confirm those benefits in patients as their disease is developing, Li said.

"I got a lot of calls from patients and other clinicians, but I told them I cannot give them a recommendation," she said.

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