Just before the holiday season, Merck announced that it was halting a major clinical trial with its cardiovascular (CV) disease drug, Tredaptive. Tredaptive is a drug which combines extended-release niacin with laropiprant. Niacin (also known as Vitamin B3) is a drug that has been used for decades to help patients control dyslipidemia. Basically, niacin is one of the few compounds known to raise HDL, the so-called good cholesterol, albeit modestly. It has been prescribed to patients at risk for heart disease with abnormally low HDL. Like all drugs, niacin comes with side-effects. In particular, dermatological effects such as itching, rashes and intense flushing are often seen with niacin. These can be so bothersome that patients who experience these effects will stop taking niacin, thus limiting the potential use of this medicine. Merck sought to solve the niacin flushing problem by coming up with a drug that prevented the dermatological effects from occurring, and discovered laropiprant with this in mind. In clinical studies, Tredaptive worked beautifully. When laropiprant was studied in combination with niacin, niacin’s HDL elevating effects were maintained and flushing was greatly minimized. After further clinical trials, Merck was able to get regulatory approval for Tredaptive in 2008 in Europe and other countries outside the U.S. Basically, Tredaptive was viewed by regulators as an improvement to niacin which was a well studied drug that had been prescribed to millions of patients over many years.
