Pfizer, Glaxo anti-smoking drugs need warning -FDA

U.S. health officials on Wednesday ordered Pfizer Inc and GlaxoSmithKline PLC to add strong “black box” warnings on their anti-smoking drugs to highlight the risk of serious mental health problems, including suicidal thoughts.

The warnings, which must be added to Pfizer’s Chantix and Glaxo’s Zyban, follow thousands of reports of depression, hostility and other behavioral changes, the Food and Drug Administration said.

The agency is also requiring the companies to conduct additional clinical trials to help determine how serious a problem the mood disorders are in patients taking the smoking cessation drugs, including among patients who already have depression or other similar conditions.

While the drugs are effective, “the possible risk of serious adverse events occurring while using these drugs should always be weighed against the significant health benefits of quitting smoking,” said Dr. Curt Rosebraugh, who oversees the FDA office that reviews smoking-cessation drugs.

Additionally, the agency strengthened its caution about possible accidents and serious injuries with Chantix but stopped short of adding it to the boxed warning as some advocates have urged.

The warnings will hamper Pfizer’s ability to advertise Chantix, which the world’s largest drugmaker had been counting on to revive profits. Instead, it has seen the drug’s sales plunge over the last year amid safety concerns. Global first-quarter sales of Chantix fell 36 percent to $177 million.

FDA first alerted patients and doctors about possible mood changes in November 2007 and since then has continued to receive a growing number of reported problems, though it said it could not directly link them to use of the drugs.

Overall, the agency received 4,762 reports of serious psychiatric events since Chantix’s approval in 2006. For Zyban and its generic rivals, it received a total 527 reports, it said.

Specifically, the FDA said it received 98 reports of suicide and 188 reports of attempted suicide with Chantix and 14 reports of suicide and 17 attempts with Zyban and related generics.

Chantix, also known as varenicline, is designed to stimulate a type of nicotine receptor in the brain while preventing nicotine from binding to another receptor.

Zyban includes the same active ingredient, bupropion, as Glaxo’s antidepressant Wellbutrin, which already carries a boxed warning about suicide and other behavioral risks.

Both Pfizer and Glaxo said they would add the warning to their products.

Pfizer said it has already begun studying Chantix in hundreds of schizophrenia patients and was planning another trial that would include people with and without psychiatric disorders.

“The benefits of Chantix outweigh the risks for many patients when used as directed,” said Dr. Briggs Morrison, a Pfizer senior vice president.

By Susan Heavey
WASHINGTON (Reuters)