Merck Says New Painkiller is Safer on Stomach ; Lack of Heart Safety Data May Delay Approval

Less than three weeks after withdrawing its Vioxx pill, Merck & Co. forged ahead with its new painkiller Arcoxia on Tuesday, saying a study showed it was easier on the stomach than an older medicine.

But the drug maker may lack enough data on Arcoxia’s heart safety to get the drug on the market. Cardiovascular safety is sure to be a major focus of federal regulators after Merck withdrew Vioxx because the drug showed it doubled the risk of heart attack and stroke.

Arcoxia, which is under review by the Food and Drug Administration, is critical to a resurgence for Merck, which saw $2.5 billion in annual sales vanish with the Vioxx withdrawal. The Whitehouse Station-based company lost nearly $27 billion in market value the day of the recall, and is bracing for a barrage of lawsuits.

Although not the focus of Tuesday’s 7,000-patient study, the results showed that Arcoxia did not carry higher heart risks compared with the older pain medicine, diclofenac. But the Arcoxia study lasted only one year, while higher risks started showing up with Vioxx after 18 months of use.

The deadline for the FDA to respond to the Arcoxia application is Oct. 30. Many analysts doubt the agency will approve the drug until it reviews more safety data.

“Arcoxia remains a key product for Merck,” said Sena Lund, an analyst with Cathay Financial LLC. “The question in my mind remains what the FDA is thinking.”

Merck officials continued to express optimism for Arcoxia’s prospects.

“We’ve demonstrated in this development program a role for Arcoxia,” said Dr. Sean Curtis, a senior director for clinical research for Merck Research Laboratories, speaking from the American College of Rheumatology conference in San Antonio, where the study was presented.

Like Vioxx, Arcoxia is part of class of drugs called Cox-2 inhibitors. Used primarily by arthritis patients, Cox-2s are designed to cause fewer ulcers and other serious stomach problems endured by those who use older painkillers such as ibuprofen.

In Tuesday’s study, 50 percent fewer patients stopped taking Arcoxia because of stomach problems than diclofenac.

Dr. Herbert Baraf, the study’s lead investigator and director of the Center for Rheumatology and Bone Research in Wheaton, Md., said that the stomach safety that can come with Cox-2s is a significant issue.

“One has to keep in mind that the promise of the Cox-2s and the benefit of the Cox-2s can’t be lost in the fog of this inexplicable cardiovascular data” for Vioxx, Baraf told reporters.

As a secondary result, the study also showed similar rates of heart attack and stroke between Arcoxia and diclofenac.

However, more people quit taking Arcoxia because of hypertension than those taking the older drug. Merck said that result differed from previous studies, which showed similar rates of patients quitting because of hypertension in comparing Arcoxia to other pills.

Merck is conducting another study on Arcoxia involving more than 23,000 patients that looks more specifically at heart safety. That study will finish by early 2006, Curtis said.

One possibility for Arcoxia’s fate is that regulators will delay the drug until the results are reported from that latter study.

Even if Arcoxia wins approval this month, doctors may be reluctant to prescribe it until seeing long-term data, Lund said.

Wall Street may learn more about the financial impact of the Vioxx withdrawal on Merck on Thursday, when the company is scheduled to report third-quarter results.

Shares of Merck rose 26 cents to $31.16 on Tuesday, although they have continued to drift down since the Vioxx bombshell was announced Sept. 30.