Novartis has finally introduced its COX-2 inhibitor Prexige in Europe, officially launching the drug in the UK yesterday after receiving marketing approval there in 2003.

The launch comes at a difficult time for the COX-2 inhibitor class, reeling from the shock of the withdrawal of Merck & Co’s Vioxx (rofecoxib) in 2004, after the drug was linked to an increased risk of heart attack and stroke. After Pfizer’s Bextra (valdecoxib) went the same way as Vioxx, Novartis decided to hold off launching Prexige (lumiracoxib), while it carried out additional clinical testing on the product.

The UK is the first European market for Prexige, although it debuted in Brazil last July, is also available in Australia, New Zealand and several Latin American countries and is approved in a total of 24. A roll-out in the rest of Europe will take place during the remainder of 2006.

The problems besetting the COX-2 inhibitor class make estimating Prexige’s sales potential hard, but analysts said it is unlikely to become the $1 billion dollar product once predicted. Nevertheless, Prexige enters a market that has been altered beyond recognition by safety issues concerning not just the COX-2s but also other non-steroidal anti-inflammatory drugs, and could benefit from the therapeutic 'vacuum' caused as a result.

Last year, a US Food and Drug Administration concluded that Prexige had a slightly increased cardiovascular risk - in common with other COX-2 inhibitors - but said there was no firm evidence to suggest the class conferred a greater risk than non-selective NSAIDs.

Meantime, a recent report on the arthritis pain market by Decision Resources concluded that after seeing ‘substantial’ losses in 2005, the sector would shrink by around 5% a year from 2006 to 2009. But DR predicts it will stage a recovery with growth of around 6% a year out to 2014, and cites Prexige, as well as another COX-2 inhibitor from GlaxoSmithKline (GW-406381) and NicOx’ NO-naproxen, as the drivers of that growth.

Novartis notes that the COX-2 inhibitor has been extensively studied with a clinical data base of more than 34,000 patients, claimed to be the largest body of evidence supporting the launch of an NSAID. These indicate that it has a gastrointestinal safety profile superior to that of two much-used NSAIDs, ibuprofen and naproxen, but also that there was no significant difference in cardiovascular risk, such as heart attack or stroke, for lumiracoxib compared to the NSAIDs.

The results of the TARGET trial showed that Prexige provided a significant 79% reduction in the incidence of upper GI ulcer complications among non-aspirin users. In patients taking low-dose aspirin, there was a numerical (21%) but not statistically-significant difference in GI benefit in favor of Novartis’ drug.

Overall, the study did not support a clear distinction between lumiracoxib and naproxen and ibuprofen in cardiovascular risk.