Pfizer Inc Thursday posted that it is stopping recruitment of patients into a heart failure clinical study involving its drug Inspra as if now on account that the study has touched its main efficacy goal early.

Professor Faiez Zannad, Co-chair of the study's executive steering committee, explained, "It is not common for clinical studies to conclude early for reasons of efficacy".

The trial, reported to be conducted in a NHYA II chronic systolic heart failure population aimed to test 3,100 patients, had an estimated conclusion date around October.

An independent committee keeping a track of the study discovered in an interim analysis that patients taking Inspra plus the current standard of care experienced a significant decrease in risk associated to cardiovascular death or heart failure hospitalization in contrast to those using placebo plus standard of care.

Pfizer posted that it has told the required regulatory agencies, ethics committees and independent review boards and investigators in countries where the trial was being conducted.

The EMPHASIS-HF trial, which was to enroll nearly 3,100 patients, involved patients surviving with mild chronic systolic heart failure.

Inspra, also known as eplerenone, is a relatively small seller for Pfizer, the world's bigger drug manufacturer.