Merck & Co has received a welcome piece of good news as European regulators have given the thumbs-up to the firm’s combination cholesterol drug Tredaptive.

Unlike the powers-that-be in the USA, the European Union have approved Tredaptive (extended-release niacin/laropiprant) for the treatment of primary hypercholesterolemia and dyslipidemia. The green-light for the treatment is based on studies involving more than 4,700 patients, Merck said, which showed that, when added to ongoing statin therapy or alone, the combo lowered ‘bad’ low-density lipoprotein cholesterol and triglyceride levels, and also increased cardioprotective ‘good’ high-density lipoprotein cholesterol levels.

What most differentiates Tredaptive from other such therapies, according to the firm, is that it can reduce the side effects of facial flushing associated with current niacin treatment, ie Abbott Laboratories’ Niaspan.

So good news in Europe but the prospects for the drug on the other side of the Atlantic are much dimmer. In April, the US Food and Drug Administration issued a not approval letter for the combo (which Merck wanted to sell as Cordaptive, a name that the agency also rejected) and demanded additional efficacy and safety data.

Then less than a month ago, Merck said that the FDA suggested that the company wait for the results of its HPS2-THRIVE cardiovascular outcomes study, which is expected to be completed in January 2013 but the firm hopes to be able to address the agency’s concerns before the end of that trial. However, 2010 is the earliest that it will be able to respond to the action letter.