New Zealand researchers have published a meta-analysis suggesting that Pfizer’s COX-2 inhibitor Celebrex doubles the risk of a heart attack.

The authors said the results, published in the Journal of the Royal Society of Medicine (March 2006), suggest that the increased risk of cardiovascular side effects that led to the withdrawal of Merck & Co’s similar drug Vioxx (rofecoxib) may be a class effect.

Celebrex (celecoxib) was found to increase the risk of heart attacks by 2.26 times compared to placebo in the analysis of four placebo-controlled studies involving more than 4,400 patients.

Celebrex remains on the market, although its sales have plummeted in the wake of Vioxx’ withdrawal. Another drug in the same family, Pfizer’s Bextra (valdecoxib), has also been removed from sale on safety concerns.

Turnover of Pfizer's COX-2 franchise brought in third-quarter 2005 revenues of $734 million, a decline of more than 60% compared to the same period of 2004, when Vioxx was withdrawn.

The lead author of the study, Professor Richard Beasley of New Zealand's Medical Research Institute in Wellington, said that the findings indicate that “drug regulatory authorities need to urgently re-examine the assessment of the drug.”

The publication of the study comes at a sensitive time for Pfizer, which has just announced a court date for the first lawsuit brought by a patient claiming to have been injured by Celebrex. The 52-year-old woman is claiming that Celebrex was responsible for a stroke she suffered in February last year.