Novartis AG’s experimental heart-failure drug showed signs of restoring the organ’s function more than the Swiss company’s bestselling Diovan pill, a study found.

In a trial among 301 patients, the drug known as LCZ696 –- a combination of Diovan and a new therapy — lowered levels of a tell-tale chemical associated with heart stress 23 percent more than Diovan alone after 12 weeks of treatment, according to data presented at a cardiology conference in Munich Sunday. The study was part of the second of three phases of human testing usually needed for regulatory approval to market a medicine.

If successful, LCZ696 would be the first drug for patients with preserved ejection fraction, a condition in which the organ’s ventricles still pump out more than 40 percent of the blood that comes in, but the atrium chamber fails to supply enough blood to the ventricle to meet the body’s needs. The condition, which mainly affects women, accounts for about half of all heart failure patients.

“They wanted to see if there was any signal before they designed a big trial,” Mariell Jessup, president-elect of the American Heart Association, said in an interview in Munich. “This probably does say we should do a bigger trial.”

While the company-funded study didn’t test whether the drug actually gave the patients better functioning hearts, Novartis is considering the next steps for the treatment, said Laurie Letvak, head of development for the Basel, Switzerland-based drugmaker’s critical-care unit.

Novartis will make a decision later this year or early next year, she said.

Reduced Protein

The disease is marked by an increase in a protein called NT-proBNP. The results of the 301-patient trial, presented at the European Society of Cardiology’s meeting in Munich today, will be published in The Lancet medical journal.

The U.S. Food and Drug Administration would want evidence that the drug actually improves patients’ health before approving it, Jessup said.

“We haven’t had a trial with a BNP endpoint before,” Jessup said. “I don’t think the Food and Drug Administration would allow” approval on that result alone.

The difference between the two groups wasn’t statistically significant after 36 weeks of treatment. That’s because while patients on LCZ696 maintained lower levels of the protein, those getting Diovan experienced more of a decrease between the weeks of 12 and 36, Letvak said.

Further testing should be done on the medicine, Scott Solomon, director of noninvasive cardiology at Brigham and Women’s Hospital in Boston, said at the meeting.

“We always need trials of epic dimensions to prove safety,” said Solomon, the study’s lead author.

Diovan, which is approved for treating high blood pressure, generated almost $5.7 billion in sales for Novartis last year. The drug is also known as valsartan.

[Novartis operates a vaccine production plant and a research and development office in Holly Springs, N.C.]