Taking advantage of the power of food to boost the effectiveness of drugs could sharply lower the cost of cancer treatments, U.S. researchers said Monday.
"We can use drug interactions to our advantage," said Dr. Ezra Cohen, a cancer drug expert at the University of Chicago Cohen, whose work appears in the Journal of Clinical Oncology.
He and colleague Mark Ratain analyzed data from a recent clinical trial showing how food affected GlaxoSmithKline's new breast cancer pill Tykerb, known generically as lapatinib.
The drug is supposed to be taken on an empty stomach. But taking it after a full meal would boost the amount of the drug circulating in the body by 167 percent, and taking it after a high-fat meal would boost it by 325 percent, the researchers found.
That might allow patients to use 40 percent less to achieve the same effect as taking it on an empty stomach. At a cost of $2,900 a month, the change could save each patient, or insurers, $1,740 or more a month, the researchers said.
And washing it down with grapefruit juice might allow patients to use as much as 80 percent less, they said. That could reduce the recommended dosage from the current five, 250 mg pills on an empty stomach to just one pill with a full meal and grapefruit juice chaser, they said.
Don't try at home
But the researchers hastened to say they are not recommending that patients try this on their own.
"The first word of caution is 'do not try this at home.' The last thing we want is to have patients take their drug with food or change the dose on their own," Cohen said in a telephone interview. "That could be potentially dangerous."
The point, he said, is that instead of looking at drug interactions with food as something to be avoided, researchers should seek ways to benefit from them.
Food sometimes enhances the effectiveness of drugs because some foods are broken down by the same processes that the liver uses to break down drugs. If liver enzymes are all busy working on the food, they are not available to break down as much of the drug, meaning it circulates for longer in the system.
Cohen and Ratain are currently studying the effect of grapefruit juice, which is known to delay the breakdown of many drugs, on Wyeth's immune suppressant drug sirolimus or Rapamune, but there are many possibilities.
"The list can go on and on in terms of the agents that could be favorably modified to reduce dose and perhaps specific side effects," Cohen said.