Canada’s drug regulator has put the lid firmly back on the potential re-sale of Pfizer’s COX-2 inhibitor Bextra (valdecoxib) in the country and, on Friday, informed the public that the arthritis drug would not return to the market.

Pfizer pulled Bextra in April after concerns arose of a class cardiovascular effect for the COX-2s, following the global withdrawal of Merck & Co’s Vioxx (rofecoxib) in 2004.

Bextra is one of a small group of drugs called COX-2 selective inhibitor non-steroidal anti-inflammatory drugs, which have been shown to increase the risk of heart attack and stroke when used for long-term treatment. In addition, says Health Canada, studies have also showed that these side effects can occur when Bextra is used for short-term pain relief following high-risk heart surgery. The compound has also been linked to a risk of rare but severe and potentially fatal skin reactions.

Now, just Pfizer’s Celebrex (celecoxib) and injectable offering Dynastat (parecoxib) remain on the market – but with much-diminished sales. The latter also comes with a warning of potentially serious hypersensitivity reactions slapped on its labelling in many countries around the world and, in the USA, it failed to get a thumbs up from the Food and Drug Administration advisory committee in September.

This latest news will be a blow to Pfizer, which previously said that it “respectively disagreed” with the decision to pull Bextra from the market and would review its options with a view to re-marketing the drug, which brought in 2004 sales of $1.3 billion. However, Health Canada said there is insufficient evidence to establish the safety of Bextra for its recommended use.