The US Food and Drug Administration (FDA) has approved Pfizer's antismoking pill, varenicline(Drug information on varenicline) (Chantix). The first new prescription medication approved for smoking cessation in nearly a decade, varenicline received priority review designation by the FDA because of its potential to be a significant therapeutic advance over existing therapies.

Unique Mechanism

Varenicline is unique because it is specifically designed to partially activate the nicotinic receptor and reduce the severity of the smoker's craving and the withdrawal symptoms from nicotine(Drug information on nicotine). Moreover, if a person smokes a cigarette while receiving treatment, varenicline has the potential to diminish the sense of satisfaction associated with smoking. This may help to prevent the cycle of nicotine addiction.

"Pfizer's discovery and development of Chantix demonstrates groundbreaking science leading to the first prescription treatment aimed directly at smoking cessation in nearly a decade," said Hank McKinnell, chairman and chief executive officer of Pfizer. "Smoking harms nearly every organ in the body. It is responsible for approximately one in five deaths in the US and costs the US health-care system about $167 billion annually. This medical advance from Pfizer will now help many smokers end their addiction."

Pivotal Trials

Varenicline's approval was based on a comprehensive clinical trial program including four pivotal trials involving more than 2,000 cigarette smokers. Subjects on average had smoked about 21 cigarettes per day for an average of approximately 25 years. In two identically designed studies, patients receiving a 12-week course of varenicline therapy (1 mg twice daily) nearly quadrupled their likelihood of quitting compared with those taking placebo, and had nearly twice the likelihood of quitting compared with those patients taking buproprion (150 mg twice daily), after the 12-week course of therapy. Enrolled patients were provided with educational materials.

Patients were followed for an additional 40 weeks without treatment. After 1 year, approximately one in five patients who received the 12-week course of varenicline remained smoke-free. For patients who quit at the end of 12 weeks, an additional 12‑week course of varenicline resulted in a greater likelihood of long-term success in quitting smoking.

Never Too Late

"These results suggest Chantix is a significant advancement," said Dr. Cheryl Oncken, a varenicline clinical investigator and associate professor of medicine at the University of Connecticut Health Center. "It is never too late to quit smoking. People who quit smoking before the age of 50 have one-half the risk of dying of a smoking-related illness in the next 15 years compared to those who continue smoking. Patients who are unable to quit on their own should consider seeking medical support and treatment."