Antismoking drugs go up in smoke
Anti-smoking treatments offer a way to help smokers kick the habit, but how effective are they really?
NEW YORK (CNNMoney.com) -- For millions of frustrated smokers, drugmakers promise to help them quit with a little pill. But studies from the companies themselves don't show very promising results.
"The drugs are approved because they've shown in FDA studies that they're better than placebo," said Dr. Edward Levin, a psychopharmacological researcher at Duke University Medical Center in Raleigh, N.C. "But being better than placebo doesn't take a whole lot, so there really is room for improvement."
Pfizer's (PFE, Fortune 500) Chantix is the most effective therapy in quitting smoking, according to test results from a company-funded study conducted by Dr. Douglas Jorenby of the University of Wisconsin School of Medicine and Public Health. During the 12 weeks that patients were on the drug, a little less than half were able to quit smoking.
But a more important figure to look at is Chantix's success rate when the patient stops using it after 12 weeks, according to Pfizer's recommended dosage. The number of smokers who have still quit after a year falls by half to roughly one in four, compared with one in ten who were on a placebo.
"The patient may have to go through this quitting process many times," said Dr. Martina Flammer of Pfizer, senior medical director of the Chantix global medical team. "It is inherent of the nature of nicotine addiction that the patient may actually relapse."
Jorenby's study, published in 2006 in The Journal of the American Medical Association, found that Chantix is better than GlaxoSmithKline's Zyban, which had weaker success rate: 14.6% of smokers had still quit after one year compared with 10.3% for placebo.
"Most people in the field would agree that there is room for improving," Jorenby said in an email to CNNMoney.com.
On its Zyban label, Glaxo (GSK) says its drug is 19% effective at six months, but it does not provide figures for one year. Dr. John Ascher, a director of clinical development for Glaxo's psychiatry division, said his company has not conducted a head-to-head study comparing Zyban to Chantix.
Anti-smoking drugs also carry serious health risks of their own. The Food and Drug Administration safety labels for Chantix and Zyban both carry warnings related to suicide. Chantix's label was updated in January to include a warning of "suicidal ideation and suicidal behavior" associated with the drug. Zyban is the same drug as Glaxo's Wellbutrin, an antidepressant. Like other antidepressants, it carries a warning of "suicidal thinking and behavior" in children, adolescents and young adults.
The market for the drugs is growing, despite skepticism about their effectiveness and safety. Research firm Datamonitor projects that the prescription market for anti-smoking therapies, worth $213 million in 2006, will balloon to $4.6 billion by 2016. This is in addition to the $2 billion market for nicotine replacement therapies, like inhalers and gum.
Chantix is the biggest driver so far, entering the market in 2006 and ramping up to $880 million in sales in 2007. But much of Datamonitor's projected sales increase is forecast to come from anti-smoking vaccines, which would work by building up anti-nicotine antibodies. These vaccines are still in development.
The first, NicVAX from Nabi Biopharmaceuticals, could enter the market in 2010, with annual sales of $700 million by 2016, said Datamonitor. NIC-002, an experimental vaccine from the Swiss partners Novartis (NVS) and Cytos Biotechnology, wouldn't enter the market until 2012, said Datamonitor, but annual sales would surge to $1.3 billion by 2016, bolstered by the vaccine's "strong efficacy, combined with Novartis' strong sales and marketing experience."
Nabi (NABI) spokesman Greg Fries said that NicVAX works by prompting the body, through a series of vaccinations, to produce antibodies that "capture" the nicotine molecules and prevent them from crossing the blood-brain barrier. But studies so far have shown NicVAX to have a just a 16% success rate after 12 months, compared with the 6% seen with a placebo, said Fries.
NIC-002 has shown promise. In studies so far, the vaccine has been 42% effective after 12 months in patient groups with the highest antibody response, according to Cytos. But this success rate represents only a subgroup of smokers where the vaccine was most effective. In other groups it was 26% or 21% effective, compared with a placebo success rate of 21%, Cytos said. Late-stage studies have yet to be conducted.
Smokers quit an average of eight to 11 times, according to the American Legacy Foundation, an anti-smoking group. For now, Chantix appears to be the best bet, even though the odds of quitting are still stacked against them.
Dr. David Gonzales, co-director of the Smoking Cessation Center at the Oregon Health & Science Center in Portland, conducted a Pfizer-funded study comparing Chantix to Zyban, just like his collegue Jorenby. Like Jorenby, Gonzales found that Chantix works better than Zyban and published the results in JAMA.
But smokers shouldn't have "false expectations" about Chantix and other drugs, which aren't completely effective because they address only the physiological parts of the addiction, not the behavioral, according to Gonzales. For that, they should get counseling.
"There's nothing out there now that you can take that will make you not smoke," said Gonzales, "That's what people think these drugs do, but they don't do that. The drugs do a reasonable job with suppressing withdrawal, but they don't teach people how not to smoke."