Days after Australia took Novartis’ osteoarthritis COX-2 inhibitor Prexige off the market, it has emerged that regulators in Canada are looking at new data to decide whether it will follow suit.

Health Canada said it is currently requesting and reviewing new safety information regarding serious liver adverse events in patients using Prexige (lumiracoxib), which were reported in Australia. The latter country’s Therapeutic Goods Administration recently withdrew market authorisation for the drug due to eight reports of serious liver adverse events in Australia linked to the drug, including two deaths and two liver transplants.

In Canada, Prexige was authorised for sale in November 2006 for acute and chronic treatment of the signs and symptoms of knee osteoarthritis, and in July 2007 for general osteoarthritis, and its current label warns against use in patients with severe liver problems. “Due to safety concerns associated with all Cox-2 inhibitor drugs,” the agency said, “there is a comprehensive post-market programme for monitoring the safe use of Prexige.

However Health Canada did note that the adverse events in Australia were seen in people who took 200mg and 400mg doses daily, whereas the recommended in Canada is 100mg. Once it has reviewed the available data, new information will be made public, including any resulting recommendations, though no timescale has been given for the project.

In the meantime, Health Canada says that Prexige “should be limited to the lowest effective dose for the shortest possible duration of treatment”. The regulators’ move and the Australian withdrawal have served to focus more attention on Novartis’ efforts to get the go-ahead for Proxige in the USA to add to the 50 or so other countries where it is approved. The US Food and Drug Administration has pencilled in September 26 as its action date.