A synthetic form of a
hormone that ramps up during pregnancy might prove to be a powerful new drug
against tough-to-treat heart failure.
Researchers who presented
data from a study this week at the American Heart Association annual meeting in
Los Angeles said the drug, serelaxin, shows promise.
But experts were cautious,
saying the findings need to be repeated in larger trials.
"If we did replicate
this finding, it would be an extraordinary advance in the care of acute heart
failure, for which we have no disease-modifying or life-saving therapies,"
said Dr. John McMurray, professor of cardiology at the University of Glasgow,
in Scotland, who commented on the study during an AHA press briefing.
Serelaxin is the lab-created
version of a natural hormone in men and women called human relaxin 2. Relaxin
circulates in low levels in humans, but spikes dramatically in women during
pregnancy.
As study author Dr. John
Teerlink explained at the briefing, "pregnancy is a physiologic state
where there are marked improvements in cardiac, arterial and [kidney] function,
and these are exactly the kinds of changes that we'd like to see in acute heart
failure."
In humans, relaxin also has
been shown to improve blood flow and cut down on inflammation, so scientists
thought it might help fight heart failure.
In heart failure, the heart
is damaged (often by a heart attack) and becomes inefficient, leading to
chronic weakness and shortness of breath. The condition is often fatal, and
there has been no real advance in treating the disease for decades.
In the study, Teerlink and
his colleagues randomly assigned more than 1,600 hospitalized heart failure
patients with an average age of 72 to receive either 30 micrograms per day of
serelaxin or a placebo via a 48-hour infusion.
Patients received the
medication within 16 hours of their hospitalization due to shortness of breath
plus a drop in kidney function. They also were given standard diuretics to help
remove excess liquid from the body and to ease swelling.
Three-quarters of the
patients in the study were men, and they tended to be very sick, with multiple
conditions such as high blood pressure, high cholesterol, heart disease,
diabetes and prior stroke.
Serelaxin did seem to have a
benefit, with shortness of breath easing by 20 percent on average, Teerlink
said. The team found that patients on the medication also had 43 percent fewer
episodes of heart failure symptoms while in the hospital, they cut short their
stay in the ICU by half a day on average and their total hospital stay was cut
by a full day on average, compared to patients taking the placebo.
Over the longer term, the
researchers reported, patients taking serelaxin were 37 percent less likely to
die from any cause (including heart disease) six months after beginning
treatment, compared to those on placebo.
There was one unusual
finding, however: Use of the drug did not cut down on
rehospitalizations, nor did it cut down on deaths from heart failure
specifically.
McMurray said that finding
has made him a little cautious in his response to the study. "It's very
unusual to see a treatment in heart failure that can improve survival but not
reduce rehospitalization," he said.
The drug's safety profile
seemed fine, however. "Serelaxin was well-tolerated and safe, with no
differences in adverse events or serious adverse events" between the
treated and placebo groups, said Teerlink, who is a professor of medicine at
the University of California, San Francisco.