Almost half of sales visits by pharmaceutical company representatives advocating the use of the drug gabapentin led to doctors stating that they intended to increase their prescription of the drug or recommend it to colleagues, according to an analysis of a survey completed by the doctors shortly after the visits.
Nearly 40 percent of the visits involved discussion of so-called "off-label" uses of the drug not approved by the Food and Drug Administration, say the authors of the study.
At the time of the visits, gabapentin was approved only for secondary treatment of a certain form of epilepsy. Off-label uses included treatment of pain, migraine, and psychiatric conditions.
"The increased intention to prescribe after these sales visits is remarkable, and is in fact greater than has been observed in other studies," says lead author Michael A. Steinman, MD, a staff physician at the San Francisco VA Medical Center (SFVAMC).
The senior author is Lisa Bero, PhD, professor of clinical pharmacy and health policy studies at the University of California, San Francisco (UCSF) and an expert on pharmaceutical industry marketing practices.
The authors analyzed a survey form that chronicled 116 visits to 97 physicians by pharmaceutical sales representatives from 1995 to 1999. The forms were collected by a market research firm and became available to the researchers as the result of a lawsuit against Parke-Davis, the maker of gabapentin. The lawsuit was brought by a former employee who alleged that the company promoted gabapentin, which it sold under the name Neurontin, for uses not officially approved by the FDA.
"To me, the remarkable thing is how effective a very brief visit by a drug representative ---- most often less than five minutes ---- can be in influencing physicians' choices to use a drug for an unapproved indication," Bero said.
After 46 percent of the visits, the doctors expressed the intention to increase either their prescribing of gabapentin or their recommendations that their colleagues prescribe the drug.
During 39 percent of visits, the sales representative either gave or promised free drug samples to the doctor, says Steinman, who is also an assistant professor of medicine at UCSF.
During 38 percent of the visits, the "main message" involved discussion of at least one use of gabapentin that was not approved by the FDA at the time, he says. "We can't say for sure whether these off-label uses were brought up by the sales representatives or the physicians," cautions Steinman, "but it's clear there was extensive discussion of uses that were not approved by the FDA ---- which, in general, sales representatives are prohibited from discussing in an unsolicited manner."
Steinman observes that off-label uses for gabapentin "represented a much larger potential market" than the officially approved use, "so there was certainly incentive for Parke-Davis to encourage the use of gabapentin for these other conditions."
He notes that physicians were just as likely to say they intended to increase prescription of gabapentin whether or not visits included mention of off-label use. Neither the duration of visit nor the visit's perceived educational value made any detectable difference in intention to prescribe, he says. "We can't rule out small differences in effectiveness. That said, even short visits of mediocre educational value were about as effective as longer visits of high educational value," he concludes.
There was no indication of whether the physicians followed up on their stated intention to prescribe more gabapentin, he says. "We can only say what, at that moment, they intended to do in the future, which is a major limitation of the study. We can't say the doctors wouldn't have increased their use of gabapentin anyway, without the visit."
Steinman speculates that the real effectiveness of pharmaceutical sales visits lies primarily in the "relationship-building" that occurs during those visits. "Aside from free drug samples, the representative will often bring a gift ---- lunch for the doctor and his or her staff, new pens and coffee mugs, offers to attend an educational conference. As a result, the doctor feels subtly, even subconsciously, indebted to the representative. This can lead to higher prescribing."
He adds, "This feeling of obligation to reciprocate a favor is not unique to doctors. It's human nature."
Steinman says that the form provides "a window into the sorts of things that can happen" during visits by pharmaceutical representatives to doctors' offices. "Today, many pharmaceutical companies officially discourage any and all discussion of off-label drug uses by sales representatives," he acknowledges.
"Nonetheless," he says, "physicians and the pharmaceutical industry don't have a great track record of self-policing in this area." He says that "there may well need to be a role for some sort of careful oversight to ensure that we don't slip back into practices that are problematic. We need to be careful of hidden forms of marketing."
The study appears in the April 24, 2007 issue of PLoS Medicine. Co-authors of the study were G. Michael Harper, MD, Mary-Margaret Chren, MD, and C. Seth Landefeld, MD, of SFVAMC and UCSF. Steinman, Landefeld, and Chren served as unpaid expert witnesses for the plaintiff in the litigation from which the source data for the study was obtained.
The study was supported by funds from the Veterans Health Administration, the National Institute on Arthritis and Musculoskeletal and Skin Diseases, the National Institute on Aging, the John A. Hartford Foundation, and the California Tobacco-Related Disease Research Programs.
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