Consumer ads for aromatase inhibitors did not prompt inappropriate prescriptions, a study has found – in fact, ads for Arimidex, Aromasin and Femara seem to have had a beneficial effect.

The researchers picked aromatase inhibitors both because the category has seen significant spending and because they could use the patient’s age as a proxy for appropriate or inappropriate use, since the drugs, which are used to prevent recurrence of breast cancer, are only effective in post-menopausal women. The question, said the study’s authors, was not whether DTC advertising was effective, but whether it was beneficial or harmful to patients.

“If DTCA causes previously undiagnosed, untreated or improperly-treated patients to receive appropriate care, it is a valuable mode of health communication,” they wrote. “If it results in superfluous or harmful new prescriptions, it is not.”

Matching TNS data on category adspend to IMS data on prescriptions for the drugs from October, 2005 to September, 2007, the researchers expected to see broad effects from DTC. “We hypothesized that there would be a significant increase in AI use associated with DTCA in all age groups,” they wrote, “both for older women for whom this treatment is appropriate, as well as for younger, presumably premenopausal women for whom such treatment is inappropriate,” a hypothesis they say assumes that viewers “will sometimes ask for the medications, even if the advertisements specify that the medications are not appropriate for them, and also that their providers will sometimes mistakenly prescribe them.”

They also tracked professional advertising in The Journal of Clinical Oncology to come up with a back-of-the-envelope estimate of professional adspend for the three drugs.

Instead of an across-the board bounce, they found that increases in advertising didn’t have any effect on prescriptions written for women 40 and under but did boost scripts written for patients 60 and up. The authors hypothesized that the finding could mean that the ads were simply “perfectly successful targeted marketing,” or that physicians did their job in turning away advertising-induced requests for the drugs by patients for whom they would be inappropriate.

“Our data thus suggest that this controversial form of medical communication may not be harmful for certain classes of drugs such as cancer medicines,” they wrote. “Indeed, in some situations, such as when an appropriate use is the only option, DTCA may actually be beneficial.”

The study appeared online in the Cancer, the journal of the American Cancer Society, on November 6.