September 2, 2008 / 9:02 AM / 11 years ago

Bristol, Pfizer drug ups bleeding in heart study

MUNICH, Sept 2 (Reuters) - Bristol-Myers Squibb (BMY.N) and Pfizer’s (PFE.N) apixaban blood clot preventer raised rates of bleeding in a 6-month study but showed some encouraging signs of protecting at-risk heart patients, researchers said on Tuesday.

The highest dose of the experimental drug had to be discontinued because of unacceptable rates of bleeding. However, there was a non-statistically significant trend suggesting patients on the drug had a lower risk of heart attack or stroke.

Apixaban, which works through a new mechanism of action by blocking a protein called Factor Xa, suffered a setback last week when it failed its primary goal in a late-stage trial for preventing clots after orthopaedic surgery.

That puts it at a disadvantage to a rival Factor Xa product called Xarelto from Bayer BAYG.DE and Johnson & Johnson (JNJ.N), which has been shown to work after surgery.

Despite this, Bristol-Myers and Pfizer hope to prove that apixiban still has a future.

Attention is now switching to its use in chronic conditions like acute coronary syndrome (ACS), an umbrella term covering symptoms ranging from severe chest pain to heart attacks, and atrial fibrillation (AF), a common heart arrhythmia.

Data from a dose-ranging Phase II clinical study involving 1,715 patients found 5.7 percent of ACS patients given 5 mg a day of apixaban on top of standard therapy experienced major bleeding or clinically relevant non-major bleeding, as did 7.9 percent of those on 10 mg.

That compared to 3.0 percent for patients who took a placebo pill plus standard therapy, including aspirin and clopidogrel.

Clopidogrel is the generic name of Sanofi-Aventis (SASY.PA) and Bristol-Myers’ blockbuster Plavix, which is given widely to patients after a heart attack to prevent a recurrence.

Study leader John Alexander of the U.S. Duke University Medical Center told the annual meeting of the European Society of Cardiology there was a clear unmet need for new approaches in treating at-risk heart patients.

The addition of an anticoagulant drug like apixiban or Xarelto is one option, since they work in a different way to aspirin and Plavix, which stop blood cells called platelets from clumping together.

But drug developers need to get the right balance between efficacy and risk of increased bleeding caused by such drugs.

John Lawrence, leader of the apixaban project at Bristol-Myers, said he believed the bleeding profile seen was acceptable, given the potential benefits of the drug.

Apixiban appeared to reduce the relative risk of cardiovascular death, heart and stroke by 27 percent when patients took 5 mg as two daily pills and by 39 percent when they took 10 mg once daily.

The trial was not powered adequately to make this finding statistically significant.

“This is only Phase II but we are encouraged by the findings. We think they suggest that a favourable scenario is possible — improved efficacy with an acceptable increase in bleeding,” Lawrence told Reuters.

The two companies are now talking with regulators about potential Phase III plans.

Bayer, meanwhile, announced on Sunday it would start a final-stage Phase III trial of Xarelto in ACS earlier than the previously planned date of the second half of 2009. (Editing by Louise Ireland)

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