First Approval, In The USA, For Glaxo's Zyban

Glaxo Wellcome has been granted its first approval, from the US Food andDrug Administration, for the smoking cessation drug Zyban 300mg (bupropion sustained-release), which is also on the market, under the brand-name Wellbutrin, for the treatment of depression. Earlier this month, the company announced that it had received an approvable letter for the new indication, which was unanimously recommended for approval by the FDA's Drug Abuse Advisory Committee last year (Marketletter December 23, 1996).

Zyban, says GW, is the first non-nicotine product for smoking cessation. It mediates its effects through the norepinephrine and dopamine systems, mimicking the reward effect that nicotine has in the brain, but without the side effects associated with nicotine withdrawal, including irritability, anxiety and restlessness.

Positive Trial Data In two trials involving 1,508 heavy smokers (more than 15 cigarettes per day), it was demonstrated that treatment with Zyban at both 150mg per day and 300mg per day was significantly more effective than placebo in helping people obtain a four-week abstinence from smoking. In addition, treatment with Zyban 300mg for seven weeks was found to be more effective than placebo in maintaining abstinence through to week 26 of the study. The most common side effect in this trial was insomnia, experienced by 35% of the treatment group, compared to 21% of the placebo group.