Celebrex risky in high-risk patients, study finds

CHICAGO (Reuters) - Doctors should prescribe the lowest doses of Celebrex possible in patients at high risk of heart problems, researchers who did a combined analysis of six studies of the Pfizer Inc pain drug said on Monday.

The analysis suggests the potentially harmful effect of Celebrex dosage is most pronounced in higher-risk patients, researchers said at the American College of Cardiology scientific meeting.

"Patients at low cardiovascular risk should take some level of comfort," said Dr. Scott Solomon, lead researcher of the National Cancer Institute-sponsored analysis. "That wasn't so clear previously."

Doctors should exercise caution in prescribing the drug, generally known as celecoxib, in high-risk patients, said Solomon, whose analysis was also published online in the journal Circulation.

Celebrex belongs to a class of pain drugs known as cox-2 inhibitors and is the only such drug still on the market in the United States. Merck and Co Inc withdrew its widely used cox-2 drug, Vioxx, from the market in 2004 after a study showed it doubled the risk of heart attack and stroke in long- term users.

Another cox-2 inhibitor from Pfizer called Bextra was also pulled from the U.S. market due to safety concerns.

While the analysis sheds light on how the drug should be used, Solomon said he could not judge whether the data lift the cloud over this class of drugs.

The six trials involving a total of 7,950 patients all studied Celebrex against a placebo for uses other than arthritis. Patients received either 400 milligrams once a day, 200 mg twice a day, or 400 mg twice a day.

The primary goal of the pooled analysis was an assessment of the combined risk of cardiovascular death, heart attack, stroke, heart failure or events involving blood clots.

Researchers found the heart risk was lowest at the 400 mg daily dose. They found nearly a two-fold risk of adverse heart events with the 200 mg twice daily dose and that jumped to about a three-fold risk at the 400 mg twice daily dose.

"Even 400 mg once a day showed elevated risk" in the high-risk population, Solomon said, adding he could not extrapolate whether doses lower than 400 mg cut risk further.

The increased risk was not affected by aspirin use, researchers said.

"Most of the data used in this pooled analysis have previously been published and are consistent with what we already know about the cardiovascular risks of Celebrex and other prescription arthritis pain relievers," said Gail Cawkwell, Pfizer's executive medical director.

"The analysis doesn't provide any new conclusions on the FDA-approved doses of Celebrex, including the most commonly prescribed dose of 200 mg daily," she said.

Dr. Steven Nissen of the Cleveland Clinic, who has a study on lower doses underway, added: "There aren't long-term randomized placebo-controlled trials for that dose, The only way we're ever going to answer these questions is with good randomized prospective data," he said. "We'll tell it like it is when the data is in."

(Writing and additional reporting by Bill Berkrot in New York, and Julie Steenhuysen in Chicago, editing by Dave Zimmerman/Andre Grenon)