Atopaxar, a new drug being developed by Japanese drugmaker Eisai, could cut blood clotting in cardiovascular diseases without serious risks of bleeding that is common with the current antiplatelet therapies.
Code-named as E5555, atopaxar has been found significantly cutting down deaths from cardiovascular diseases like heart attacks, strokes, studies have shown.
Atopaxar is a protease-activated receptor 1 (PAR-1) inhibitor that targets thrombin-induced platelet activation.
The experimental drug works differently from that of aspirin and other antiplatelet medications such as clopidogrel and ticagrelor.
Eisai has conducted two phase 2 clinical studies on atopaxar. One study involving more that 500 patients with either acute coronary syndrome or high-risk coronary artery disease showed that atopaxar could reduce incidence of heart problems to low levels compared with those on placebo.
Patients taking E5555 in the two Phase II trials demonstrated a numerically lower incidence of heart problems compared with those on placebo but Goto said the overall number of events was very low and the studies were not powered to show efficacy.
One of the trials involved 241 patients with acute coronary syndrome and the other 263 patients with high-risk coronary artery disease.
Atopaxar showed effective blocking platelet aggregation in the studies. Over 90% inhibition of platelet aggregation was achieved with doses of 100 mg and 200 mg while the inhibition rate was 20% to 60% inhibition was achieved with a dose of 50 mg in both study groups.
There was a tendency of increased bleeding incidence with higher dose of atopaxar. The researchers, however, said the dose-dependent trend was numerical and was not statistically significant.
“My personal opinion is that there is no reason not to go ahead with phase 3 trials of this drug,” Dr Shinya Goto, Tokai University School of Medicine, Japan was quoted as saying to Heartwire.
When it comes to the standard dose levels 100 mg per day can be recommended or additional phase 2 studies could be performed testing a dose of 75 mg per day, according to Dr Goto who published the findings simultaneously in the European Heart Journal, and presented in a hot-line session at the European Society of Cardiology 2010 Congress.