EMEA counsels COX-2 action

The European Medicines Agency (EMEA) has concluded its investigation into the risk/benefit balance of COX-2 inhibitors, and has called for the marketing authorisation for Pfizerís Bextra to be suspended.

All COX-2 inhibitors remaining on the market in the EU should have new contraindications and warnings imposed upon them, the agency noted. However, when prescribed within the official constraints, ëthe balance of benefits and risks remains positiveí, it added.

With Vioxx already removed from the global market, the EMEA judged that Bextra (valdecoxib) should also be withdrawn from EU markets as it presented not only the cardiovascular risks that plague all currently marketed COX-2 inhibitors, but is also linked with potentially fatal skin reactions. Therefore, the risks outweigh the benefits, the agency found.

Pfizer had already voluntarily agreed in April this year to withdraw Bextra from EU markets, following a request by the EMEA. The company will have the opportunity to seek to have the product made available again, as there will be a review of the suspension of its marketing rights for the drug within one year. Until this time, Pfizer is permitted to provide further ësafety and other relevant dataí to support its case for Bextra to be considered for re-introduction.

With regard to other COX-2 inhibitor pain relievers available within the EU, which include celecoxib (Celebrex; Pfizer), etoricoxib (Arcoxia; Merck & Co), and parecoxib (Dynastat; Pharmacia), the EMEA affirmed that the available data show an increased risk of ëthrombotic adverse cardiovascular reactionsí, such as heart attacks and strokes.

The agencyís Committee for Medicinal Products for Human Use (CHMP), responsible for recommending action on the use and availability of COX-2 inhibitors in Europe, also confirmed the link between duration and dose of intake of these drugs and the relative risk of suffering a cardiovascular reaction.

Official European recommendations

The EMEA recommends that:

• COX-2 inhibitors are not used in patients with established ischaemic disease and/or cerebrovascular disease, or in those with peripheral arterial disease
• Warnings should be reinforced that healthcare professionals must exercise caution when prescribing COX-2 inhibitors in patients presenting with cardiovascular risk factors, such as hypertension, hyperlipidaemia, diabetes and smoking
• Doctors should prescribe the lowest effective dose for the shortest possible duration of treatment; and
• There should be additional and strengthened warnings to healthcare professionals that hypersensitivity reactions and rare, but ëserious and sometimes fatalí skin reactions can occur, in particular during the first month of use. Patients with history of drug allergies may be at greater risk.

One company still hoping to gain marketing approval in the EU for its new COX-2 inhibitor (lumiracoxib; Prexige) is Novartis, which withdrew its original application in November 2004 following the prompt withdrawal of Merckís Vioxx.

The company declined to comment on when the approval process for Prexige might recommence, however it indicated earlier in the year that it would wait for the completion of the EMEAís safety review.

Novartis claims that Prexige has a similar cardiovascular safety profile to other COX-2 inhibitors, but has a superior gastrointestinal safety profile compared with some older drugs.

Moving forward, the EMEA plans to conduct a further investigation into the safety of all non-steroidal anti-inflammatory drugs (NSAIDs), as ëit is unclear if the findings for COX-2 inhibitors are also relevant for conventional NSAIDsí.

Patients who are concerned or who have worries should consult their doctor or pharmacist, the EMEA advises.