Schering-Plough Corp has reported that its experimental anti-clotting drug, as in an earlier trial, met its main goal in two additional mid-stage trials of not increasing bleeding risk when given in combination with standard anti-clotting drugs.
The absence of additional bleeding for the experimental medicine is an important finding because of concerns that regulators might not approve a new anti-clotting medicine if its adds to the significant bleeding risk already inherent with existing treatments.
Moreover, heart patients who took Schering-Plough's so-called thrombin receptor antagonist had a statistically significant lowered risk of heart attack than those taking standard treatments, the company said.
"These are very exciting, but very preliminary results that can only be verified by larger trials," company spokesman Lee Davies said.
The favorable findings for the drug came from a pair of phase II trials conducted in Japan. The drug works by blocking receptors to a protein called thrombin that is a main factor in the clotting process.
The drugmaker disclosed on Monday it has begun two late-stage, or phase III trials, of the pill that involve nearly 30,000 patients.
Chief Executive Officer Fred Hassan in March said the medicine has potential to fetch annual multibillon-dollar sales if it is proven equally safe and effective in the larger trials and is approved.
One of Japanese trials described on Monday involved 120 patients treated for 60 days for acute coronary syndrome, meaning heart attacks or chest pains that can precede heart attack or stroke. The patients were given stents, tiny mesh-like cylinders that prop open coronary arteries which have been cleared of plaque.
Some of the patients received only standard anti-clot medicines, such as aspirin, the injectable drug heparin or Ticlid (ticlodipine), which prevent clots by blocking blood cells called platelets from sticking together. Another group received the thrombin receptor antagonist in combination with the standard anti-platelet treatments.
The second trial, lasting two months, involved 90 patients who previously had strokes. Some of those patients received only standard treatments to prevent new strokes -- including aspirin and Ticlid -- while others received the Schering-Plough medicine in combination with them.
The company noted that Ticlid is in the same class of drugs as Bristol-Myers Squibb Co's widely used anti-platelet Plavix, which has only recently been introduced in Japan.
Favorable reports of an earlier mid-stage trial of the thrombin receptor antagonist were reported in March at the annual meeting of the American College of Cardiology.
In that study, the medicine also met its primary goal of demonstrating no increase in bleeding risk. Although patients taking the Schering-Ploughdrug had 46 percent fewer heart attacks than those taking standard drugs alone, the result was not deemed statistically significant.
