New Bextra warnings add to COX-II doubts
pharmafile | October 22, 2003 | News story | |
New warnings on the label of second-generation COX-II inhibitor Bextra have added to doubts about the safety of the drug class.
Joint marketers Pfizer and Pharmacia have issued a drug warning to US physicians over potential life-threatening reactions to Bextra.
Post-marketing surveillance since the drug's US approval last November has picked up on rare hypersensitivity reactions (such as anaphylactic shock) and various severe skin reactions to the drug, which can all be fatal.
It is the latest in a series of safety issues to hit the COX-II inhibitor class, which is being investigated by the EMEA following concerns over cardiovascular complications.
Recent data published in the BMJ has linked high-doses of Merck's Vioxx to an increased risk of coronary heart disease.
Bextra is the follow-up to Celebrex, the US and global leader in the arthritis market, with sales of $3.1 billion last year, although Vioxx has the edge in Europe and UK. The launch of Merck's successor to Vioxx, Arcoxia, has been delayed until next year following an FDA request for more safety data.
Pharmacia had recently published new data showing patients taking Bextra (valdecoxib) had similar rates of GI events than those on placebo, and significantly less than those taking either naproxen, ibuprofen or diclofenac.
Furthermore, patients on Bextra showed no greater incidence of cardiovascular events than those on naproxen or placebo.
A new arthritis drug currently in development by German company Merckle may offer a better gastrointestinal safety profile than current COX-II inhibitors, according to new trial data.
The studies show licofelone can be taken in conjunction with aspirin without comprising its GI tolerability, unlike COX-II inhibitors such as Celebrex and Vioxx.
Licofelone has previously indicated its potential as a rival to the established market leaders, demonstrating similar or improved efficacy with fewer gastrointestinal side-effects and lower cardiovascular complications.
The success of COX-II inhibitors is partly due to an improved gastrointestinal safety profile over traditional NSAIDs but trials have shown when taken with aspirin they can lead to an increased risk of gastric ulceration.
The recent studies of licofelone at twice the anticipated therapeutic dose, indicated the incidence of gastroduodenal ulcers was only 5.6% in patients also taking low-dose aspirin, compared with 2.4% in patients on licofelone only. This compared with 25.6% and 23% for patients taking naproxen with and without aspirin, respectively.
"These new findings strengthen licofelone's profile as potentially providing a safe and effective treatment in all osteoarthritis patients including those who are at risk of cardiovascular disease and are therefore co-administering aspirin", said Prof Stefan Laufer, University of Tuebingen, Germany, who has been involved in the studies.
