Pfizer launches dual-mode therapy to block nicotine's effect in the brain.

Let's quit

Pfizer launches dual-mode therapy to block nicotine's effect in the brain.

PFIZER Malaysia recently launched its new smoking cessation pill, varenicline, a

breakthrough non-nicotine oral medication. It has a novel mechanism of action which helps smokers quit smoking by providing dual benefits.

Varenidine 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.

Moreover, if a person smokes a cigarette while receiving treatment, it has the potential to diminish the sense of satisfaction associated with smoking.

This assists the attempting quitter by helping prevent the cycle of nicotine dependence.

Nicotine dependence makes quitting smoking very difficult and is one of the main reasons many smokers do not succeed in their attempts to quit.

When smokers inhale smoke from a cigarette, nicotine reaches the brain within seconds and binds to nicotinic receptors, which activates the reward pathway in brain circuitry. This stimulates the pleasure centre in the brain.

However, the initial effects of pleasure recede quickly. The rewards-or pleasurable effects rein-force a smokers' physical dependence on the nicotine contained in cigarettes.

Smokers then become accustomed to certain levels of nicotine in their systems and a drop in these nicotine levels results in a cycle of craving and uncomfortable with-drawal.

"Pfizer's discovery and development ofvamnicline demonstrates groundbreaking science leading to the first treatment aimed directly at smoking cessation," said Dr Wong

Kok Seng. Medical Director, Pfizer Malaysia, Singapore and Bmnei. "Smoking harms nearly every organ in the body and is a preventable cause of death. This innovahve

medication will now help many smokers end their nicotine dependence and enjoy healthier and happier lives."

In two identically designed varenicline studies, patients receiving a 12-week course of varenicline therapy ( lmg twice daily) nearly quadrupled the likelihood of quitting than those taking placebo and had nearly twice the likelihood of quitting than those patients taking buproprion (150rag twice daily).

Varenicline also demonstrated a favourable safety and tolerability profile in studies of almost 4,000 smokers.

"These results suggest varenidine is a significant advancement in the management of smoking cessation," said Dr Wang. "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. Smokers who are unable to quit on their own should consider seeking medical support and treatment."

In trials, vareuicline was generally well tolerated, with overall discontinuation rates similar to placebo. The most common side effects included nausea, vivid dreams, headaches and vomiting.

"As everyone knows, it is extremely difficult to quit smoking," said Dr Wang. "For example, less than 7% of smokers who try to quit on their own achieve more than one year of abstinence. In fact, most smokers begin smoking again within a few days of attempting to quit. It takes about five to seven attempts -with or without treatment - before the average smoker is able to quit."

Because smokers need considerable support to successfully quit their dependency on nicotine, a support programme known as the Quitting Championship designed to help address behavioural components of smoking dependence will be made available to patients.

Recognising the need for greater awareness of the role of medical therapy in quitting smoking, Pfizer wil! also be making available to the public a Quitter's Guide, which provides information on the different options for smoking cessation therapy available in Malaysia.

"Varenicline represents Pfizer's commitment towards working together for a healthier world through applying innovative science to improve the quality of life for patients," said Dr Wang.

Unlike other smoking cessatior solutions that work only on controlling the withdrawal symptoms, varenicline reduces craving and withdrawal symptoms as well as the smoker's sense of satisfaction derived from smoking.

Both nicotine and varenicline act on the nicotinic acetylcholine receptors (nAChRs) in the brain, which is associated with nicotine dependence.

However unlike nicotine, varenicline is a partial agonist of the receptors.

References:

1. Conzales DH, Rennard SI, Billing CB, Reeves KR. A pooled analysis of varenicline, an a462 nicotinic receptor partial ogonist versus bupmpion for smoking cessation. Presented at Surety for Research on Nicotine and Tobacco, February 2006.

2. Jorenby DE, Hays ff, Rigotfi NA, et al, for the Varenidine Phase 3 Study Group. Efficacy of varenidine, an a462 nicotinic acetylcboline receptor partial agonist, vs placebo or sustained-release bupropion for smoking cessation: a randomized controlled triaIJAMA. 2006;296:56-63.

3. Tonstad S, Hays JT, Jorenby DE, Reeves K. Billing 13, Gong J, Azoulay

5. Smoking cessation efficacy and safety of an o462 nicotinic receptor partial agonist - results from varenidine in cessation therapy: optimizing results. Presented at American Heart Association, November 2005.