By Ben Hirschler

The first patients started taking the so-called "polypill" last month and a total of 600 will ultimately be recruited into the trials, doctors said on Monday.

Its backers say the new low-cost combination drug could save millions of lives, particularly in developing countries, where most heart attacks occur.

Francisco de Paula Rodriguez Perera, director of the Spanish National Centre of Cardiovascular Research, said the medicine was likely to be launched initially in Spain and parts of Latin America but could be available globally by the end of 2010.

The polypill contains three established drugs -- aspirin, a cholesterol-lowering statin and an ACE inhibitor for reducing blood pressure -- and is intended to prevent heart attack patients from suffering a recurrence.

At the moment, such patients are often required to take multiple drugs, which is expensive. They also frequently forget to take the right medicine at the right time.

The new pill is not designed for people with no history of heart attack but Rodriguez believes other polypills will become available for this group of patients in time.

"I think in five years we are going to have several different offerings in the market ... there will be polypills for different phases of treatment," he said in a telephone interview from the World Congress of Cardiology in Buenos Aires.

London's Wolfson Institute of Preventive Medicine, for example, hopes to start testing a five-in-one polypill that could be given to everyone over 55 years, irrespective of their history of disease.

Cardiologists have talked about using polypills for years but plans to produce them have been complicated by rivalry among large drug companies, who are keen to promote patented products.

Now some of the problems are falling away. Many good drugs are available today in cheap generic form and smaller companies are showing growing interest in the combination drug concept.

The Spanish polypill is being developed in collaboration with privately owned Spanish drugmaker Ferrer and several Indian drug firms are keen to become involved in the polypill market.

Rodriguez and colleague Valentin Fuster said they aimed to get the new polypill approved by both the U.S. Food and Drug Administration and European regulators.

"We expect to finish the clinical studies in the third or fourth quarter of 2009 and be out in market in the first half 2010," Rodriguez said.

Fuster said cheaper interventions such as the polypill were critical in poorer countries, where cardiovascular disease is growing alarmingly, driven by worsening diets and smoking.