Impact of food-cancer drug interactions

A commentary in the Journal of Clinical Oncology (JCO) urges researchers to explore an intriguing approach to reduce the dose, and therefore the cost, of oral targeted cancer therapies.

The commentary, by Mark Ratain, MD and Ezra Cohen, MD of the University of Chicago, examines recent pharmacologic research which found that taking the targeted therapy lapatinib (Tykerb) with food significantly increased the concentration of the drug in the body. The commentary suggests that taking lapatinib with food instead of on an empty stomach, as currently indicated, could cut the needed dose by at least 60 percent, reducing the cost accordingly. The authors stress that formal studies are needed to determine the effectiveness of this approach. The article is being published online July 16.

The commentary focuses on a study presented at the March 2007 meeting of the American Society for Clinical Pharmacology and Therapeutics, which found that lapatinib is more readily absorbed by the body when taken with food, particularly a high-fat meal. As a result, 500 mg of lapatinib taken with food may be as effective as taking the currently approved 1,250 mg without food.

Lapatinib was approved by the U.S. Food and Drug Administration (FDA) in March of this year for women with advanced HER2-positive breast cancer. The FDA approved the 1,250 mg dose of lapatinib based on a large phase III clinical trial demonstrating its effectiveness and safety at that dose without food. It is taken as five 250 mg tablets on an empty stomach and costs $2,900 per month.

The cost of new targeted cancer therapies , which can be as high as $10,000 per month , has generated substantial discussion and debate. "The economic implications of this food effect study are particularly remarkable. At the current price of $2,900 per month, this would have a cost savings of 60 percent or $1,740 per month, the commentary states. "As we enter an era of ,targeted, anticancer agents with a monthly cost measured in the thousands of dollars, we should view drug-drug or drug-food interactions as opportunities to lower costs."

The commentary states that rising cancer drug prices are encouraging researchers to explore such pharmacologic approaches to lowering costs. However, the authors urge that neither physicians nor patients consider changing lapatinib dose based on these findings, and that everyone strictly follow the prescribing label directions, which are based on the findings of rigorous clinical tests. The authors strongly emphasize that a formal pharmacokinetic study of a lower dose of lapatinib with food would need to confirm these findings before any change in dosage could be considered safe and effective.