New COX-2 scare as second painkiller withdrawn
after the FDA asked Pfizer to withdraw Bextra (valdecoxib) from the
market because the overall risk of heart disease and
life-threatening skin reactions outweighed its therapeutic
benefits.
The withdrawal of Bextra is a blow for Pfizer, the world's largest drugs firm, which has consistently denied there are risks from its arthritis drugs. The company responded by saying it "respectfully disagreed" with the FDA's decision on Bextra.
"In deference to the agency's views, the company has agreed to suspend sales of the medicine pending further discussions with the FDA," said the company in a statement. It indicated that it would "explore options with the agency under which the company might be permitted to resume making Bextra available to physicians and patients."
Bextra's withdrawal follows safety concerns about a similar arthritis painkiller, Vioxx (rofecoxib), which was voluntarily pulled from the market by its manufacturer, Merck, last year due to evidence that it caused heart attacks and strokes. Both Bextra and Vioxx are from the same class of drug, known as COX-2 inhibitors.
Earlier this year, an advisory panel to the FDA ruled that the benefits of Cox-2 drugs, some of which have been linked to increased likelihood of heart attack, outweighed the risks.
This latest development means that Celebrex is now the only Cox-2 drug on the market. It is expected to dominate sales wise from users of Bextra or Merck's Vioxx and Arcoxia. The three withdrawn medicines together generated about $3 billion (€2.3 billion) in revenues last year.
The FDA said that Bextra displayed no other unique advantages over the other available NSAIDs. In addition, there was an increased risk of serious skin reactions such as Stevens-Johnson syndrome, an allergic reaction that usually begins as a blistering of the mouth and lips and can spread to the rest of the body.
The European Medicines Agency had previously issued a statement about Bextra concerning safety issues for patients undergoing coronary artery bypass graft (CABG) surgery and serious skin reactions relating to the use of two COX-2 medicines.
The safety of COX-2 inhibitors has been constantly questioned since the withdrawal of Vioxx. In February US scientists had recommended that Bextra and Vioxx should remain on sale. European regulators are still undecided and report later this month on its decision.
The FDA also ruled that Celebrex, another Pfizer drug in the Cox-2 class, would have to carry the strongest government health warning to stay on the market.
Merck has been trying to get its second-generation COX-2 drug, Arcoxia, approved in the United States. It already has been approved in Canada and overseas. It is not the only player, either, as Novartis also has a COX-2 in the works called Prexige, and GlaxoSmithKline is working on what it calls compound 381, a new dual-acting Cox-2 inhibitor.
