Genetic variation linked with improved response to beta-blocker, say researchers
Researchers have identified a polymorphism that is associated with an improved response to beta-blockers in heart failure.
Stephen Liggett, professor of medicine and physiology at the University
of Maryland school of medicine, Baltimore, and colleagues analysed genetic
variations associated with the beta1-adrenergic receptor in a study comparing
the investigational beta-blocker bucindolol with placebo in 1,040 heart
failure patients.
The researchers found that patients with an arginine variation of the
beta1-adrenergic receptor gene (b1-Arg-389) who were treated with active
drug had a 38 per cent reduction in mortality compared with arg-389 patients
given placebo (P=0.03). Those with glycine at position 389 who were treated
with bucindolol had a similar response to those patients given placebo.
“It has been difficult to explain the variability of response to
treatment, even among patients with similar ages and other characteristics.
This
is especially the case with beta-blockers,” commented Michael Bristow,
a cardiologist at the University of Colorado and one of the study authors. “We
hypothesised that the variability in response to beta-blockers was due
to important functional genetic variation in the beta1 receptor, and
this indeed appears to be the case.”
The study is published online this week in Proceedings of the National
Academy of Sciences (www.pnas.org)
As part of their investigations, the researchers also considered genetic
variations and response to bucindolol in black patients compared with
white patients. They observed that genetics, not race, determined who
benefited from the drug. “We believe it is inappropriate to use
a race-based prescribing approach, because within any given ethnic or
racial population there is a genetic variability within that group. Therefore,
some people will have the response gene and some will not,” commented
Dr Liggett. |
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