Chantix Provides Fourth New Drug Approval for Pfizer in 2006, Fifth on the Way?

Smoking Out the Drugs

U.S. überpharma Pfizer announced yesterday that the FDA has approved its anti-smoking pill Chantix (varenicline). The green light has come slightly earlier than expected, following a priority review that took less than five months. Chantix, which was originally developed as Champix, has been renamed following negotiations with the FDA, according to a company representative who spoke to Global Insight yesterday. Pricing has not yet been confirmed, but will probably be revealed in the coming weeks.

However, Pfizer has gone into full marketing mode for a product that could have the greatest consumer brand penetration since Pfizer's own erectile dysfunction pill Viagra (sildenafil). Chantix is the first new prescription medication to be approved for smoking cessation in nearly a decade, and will immediately be positioned in the market against GlaxoSmithKline/Watson's (U.K./U.S.) genericised Zyban (bupropion). Zyban is generally priced at around US$119 per 30-tablet prescription of 150 mg, but Chantix is likely to be priced at a significant premium to this.

The primary innovation of Chantix is that it does not attempt to act as a nicotine substitute, unlike other nicotine replacement therapies (NRTs). Instead, it is designed to partially activate nicotinic receptors in the brain, in order to reduce both the craving for smoking and the withdrawal symptoms. Chantix has also been shown to reduce the satisfaction associated with smoking.

Chantix is designed to be taken according to a relatively formalised programme for quitting smoking; like Zyban, it should ideally be taken on a course of up to 12 weeks. It comes in two doses, 0.5 mg white tablets and 1 mg blue tablets, and for the first three days, one tablet of the lower dose should be taken. For the next four days the 0.5mg dose should be taken twice a day, and from then on the 1mg dose should be taken twice a day.

Outlook and Implications

In terms of convenience of use and side-effects, Chantix will not offer much improvement on Zyban. They are both twice-daily treatments, and although Zyban patients generally find sleeplessness to be a major problem, Chantix comes with its own side-effects, largely involving nausea and gas. However, in Phase III head-to-head trials, Chantix proved to be more effective than generic bupropion, offering nearly twice the likelihood of quitting smoking after 12 weeks: 44% of patients taking Champix had given up smoking at the end of that period, compared to 30% of Zyban users. A follow-up analysis after a further 40 weeks showed that 22% of varenicline patients had continued to stop smoking, compared to 16% of bupropion patients, although this differential did not reach statistical significance.

Obtaining favourable placing on reimbursement lists thus remains critical, to ensure that pricing does not get in the way of consumer acceptance. Pfizer will also be positioning itself to build up a European launch, following its filing in November 2005. The drug is expected to have sales of around US$150 million by 2007, and Global Insight maintains that current market estimates of peak sales of US$500 million are relatively modest, particularly given the failure of French drug-maker Sanofi-Aventis' Accomplia (rimonabant) in this setting earlier this year, which has removed a major potential competitor.

While rising costs and declining sales are clearly pressing on Pfizer's margins, and will continue to do so through 2006 and most of 2007, the high rate of successful R&D productivity that has already been seen this year, compared to the lacklustre 2005, provides a strong reminder that the company can still maintain a bullish position at the top of the industry. FDA action on insomnia drug indiplon is expected next week, while newly acquired urology drug fesoterodine and approvable antibiotic Zeven (dalbavancin) should also receive approval this year. However, sales of cholesterol drug Lipitor (atorvastatin) remain a major concern, and many observers believe that Pfizer's projection of US$13 billion for 2006 (from US$12 billion last year) is too ambitious; CEO Hank McKinnell's statement a year ago that Lipitor could reach peak sales of US$20 billion seem far, far away. Positives are largely emerging from Lyrica (pregabalin; nerve pain) and Geodon (ziprasidone; schizophrenia), as well as a resurgent Celebrex (celecoxib; arthritis) and Caduet (amlodipine/atorvastatin; cholesterol).

Related Articles:

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• United States: 13 February 2006: Pfizer Restores Guidance, but Not Confidence

• United States: 20 January 2006: Pfizer Full-Year 2005: Could Have Been Worse, but Still No Guidance

• United States: 22 December 2005: Pfizer's Smoking Cessation Candidate Champix Receives Priority Review

• United States: 16 November 2005: Drug Market Underwhelmed by New Data for Pfizer's Lipitor, Torcetrapib and Smoking Drug Champix