An experimental drug from Roche, a Swiss global healthcare company, designed to raise "good" HDL cholesterol has produced encouraging results in a small mid-stage clinical trial.

Further details about the performance of dalcetrapib will be released at a medical meeting in Paris next week, but analysts said a scientific abstract posted by the European Society of Cardiology at the weekend painted a positive picture.     

While dalcetrapib continues to be viewed as a high-risk project, its chances of success have improved following data from the 130-patient Phase II imaging study, showing it does not increase plaque-related inflammation on artery walls.     

Furthermore, patients on the new drug had less build-up of potentially artery-clogging plaque in their blood vessel walls than those on placebo, and the medicine was well tolerated.     

It is still early days for dalcetrapib, and medical experts remain wary following the high-profile failure of a similar drug from Pfizer called torcetrapib. There is also a lack of evidence -- so far at least -- that raising HDL with drugs actually stops heart attacks and strokes.     

But analysts believe the medicine could become a major seller if it proves itself in final-stage Phase III tests.   

Roche will have to wait for results from a much larger clinical study at the end of 2012 to see whether its medicine produces a real benefit in clinical outcomes. Still, the early signs are encouraging, with only two cardiovascular events among patients on dalcetrapib seen in the small Phase II trial, compared with 13 among those on placebo.     

Andrew Weiss, an analyst at Vontobel, currently gives dalcetrapib a 30 percent chance of success but believes the medicine could generate peak sales of 4 billion Swiss francs ($5.1 billion), if it works.     

That would make it a major product for Roche and one that would start to diversify its focus firmly beyond cancer treatments, where it is the market leader.     

However, dalcetrapib will not make its mark for a few years, and industry analysts, on average, are forecasting only a modest $203 million in annual sales by 2015, according to Thomson Reuters Pharma.     

Merck & Co also has a competitor in the HDL-raising drug race, known as anacetrapib. -Reuters