An experimental drug from Novartis to treat heart failure proved equally effective regardless of the age of patients or whether they had other medical problems, clinical trial results presented on Monday showed.

The drug, serelaxin, which is a form of a human hormone that relaxes blood vessels and eases stress on the heart and other organs, is viewed as an important medicine in the Swiss drugmaker's developmental pipeline.

Analysts at Jefferies expect the drug to generate peak sales of $1.5 billion a year.

Results from a Phase III study last November found it cut deaths by 37 percent compared with placebo - and the latest data offers further insight by showing how it performed in different patient sub-groups.

The drug led to reduced dyspnea, or breathlessness, and fewer deaths after six months in all patient groups, including those with impaired kidney function, those aged 75 or older, and those with atrial fibrillation, or irregular heartbeats.

The new findings were presented at the European Society of Cardiology congress in Amsterdam, where heart doctors have highlighted the enormous need for new treatments for acute heart failure, in which the heart is unable to pump enough blood.

Some 2 million patients are hospitalized each year in Europe and the US as a result of heart failure, and about half of all patients die within five years of being diagnosed with the condition.