Tokyo, Japan-based Daiichi Sankyo is discontinuing all ongoing clinical studies of its CS-505 (pactimibe), after the agent failed to meet primary targets in the ACTIVATE trial, which was designed to assess the agent’s efficacy in the treatment of atherosclerosis.

Analysis of the study’s secondary endpoints revealed a lower effect of the agent on atherosclerosis than standard of care alone, and no beneficial effect on the frequency of cardiovascular events. Consequently, all ongoing clinical studies with pactimibe will be terminated, and the company says it will release additional surrounding details at the 2005 American Heart Association’s Scientific Sessions on November 15.

Daiichi Sankyo had high hopes for pactimibe, a novel compound in a new class of cardiovascular drugs designed to prevent the build-up of cholesterol via inhibition of ACAT, an enzyme ultimately contributing to foam cell formation, a characteristic of early atherosclerosis. In previous animal experiments, the agent reduced the progression of the condition, the group noted.

The first drug in this class to reach the market was Schering-Plough/Merck & Co’s Zetia/Ezetrol (ezetimibe), which has seen sales quickly ramp up since its introduction in the middle of last year to reach $356 million dollars in the third quarter of 2005 [[25/10/05a]].