Pfizer Inc. and Bristol-Myers Squibb Co. halted a trial of their experimental blood thinner after an increase in bleeding outweighed benefits for patients who recently suffered a heart attack or severe chest pain.
The treatment, called apixaban, was being tested to prevent heart complications in patients with a condition known as acute coronary syndrome. Enrollment in the study of 10,800 people in 40 countries was stopped and patients will be taken off the drug, Pfizer and Bristol-Myers said in a statement.
The market for new blood thinners may surpass $14 billion in annual sales, according to German drugmaker Bayer AG, a developer of a rival treatment. Pfizer and Bristol-Myers, both based in New York, said they will continue to pursue apixaban’s approval for the prevention of strokes in patients with irregular heartbeats and clots in those who have undergone hip and knee replacement.
The heart condition tested in the trial stopped yesterday “was a much dicier indication” for the use of the drug, said Steven Nissen, head of cardiology at the Cleveland Clinic in Ohio. The study “just means this indication is not going to work out. It doesn’t mean anything for the other indications.”
The drug may still bring in $1.7 billion in sales for the two companies in 2015, said Tim Anderson, an analyst at Sanford C. Bernstein & Co. in San Francisco.
“In this particular indication, we did not have high hopes, and we built nothing into our sales forecast for this,” Anderson said in a note to clients today. “While a setback to some degree, failing in acute coronary syndrome is of little real consequence.”
Bristol-Myers fell 37 cents, or 1.4 percent, to $25.95 at 4:01 p.m. in New York Stock Exchange composite trading. Pfizer declined 3 cents to $16.80.
The trial was at least the fourth such failure this year for Pfizer. In March, the company said its experimental Alzheimer’s drug Dimebon, which analysts said could have generated $5 billion in annual sales, failed to help patients in a late-stage study. That same month, Sutent, approved for kidney and stomach cancers, failed in two studies to shrink tumors of the breast, and the experimental drug figitumumab didn’t help lung cancer patients.
The halted study, called Appraise-2, was designed to prevent recurrent episodes in patients with heart attacks and acute blood vessel blockages. Patients who suffer such attacks are especially vulnerable to have a repeat event in the following months. About 733,000 Americans are released from the hospital each year with the condition.
The excess bleeding cause by apixaban outweighed the drug’s prevention benefits, according to the companies, which didn’t disclose the number or severity of the bleeding episodes or the number of episodes prevented.
“We knew there would be an increase in bleeding,” Jack Lawrence, in charge of apixaban development at Bristol-Myers, said in a telephone interview. “The question was whether we could achieve enough incremental efficacy to offset the incremental bleeding.
“We knew going in that achieving a net favorable benefit would be a challenge,” Lawrence said.
A key use for apixaban is in patients with atrial fibrillation, an irregular heartbeat that increases the likelihood of clots. The standard drug given to those patients is warfarin, a generic treatment in use for more than 50 years that causes side effects and is difficult for doctors to properly dose.
About half of the 2.2 million Americans with atrial fibrillation can’t take warfarin and are typically given a daily dose of aspirin.
In a previously published study of 5,600 patients, those who took apixaban were 54 percent less likely to have a stroke or damaging clot than those who took aspirin. Tests comparing apixaban directly to warfarin are under way as part of eight late-stage tests the companies pursued.
“When you go up against warfarin, you go up against a pretty dirty drug,” Nissen said. For the acute coronary syndrome patients, it was more difficult to beat standard care without causing harm, he said.
The results from Pfizer and Bristol-Myers’s other studies thus far have been “quite beneficial,” said Steve Romano, vice president of Pfizer’s medical development group, in a phone interview. “This was much more challenging.”
Johnson & Johnson and Bayer AG’s blood thinner Xarelto was at least as good as warfarin in a study presented Nov. 15 at the American Heart Association’s annual meeting in Chicago. The study positions Xarelto to take at least a third of the market for warfarin replacements, following U.S. approval last month of Boehringer Ingelheim GmbH’s rival drug Pradaxa, said Savant Ahmed, a London-based analyst for the Royal Bank of Scottland, in an e-mail.
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