The following drug information is obtained from various newswires, published
medical journal articles, and medical conference presentations.
Imagent (previously known as Imavist) injectable suspension has
been approved by the FDA for use in patients with suboptimal
echocardiograms. It is indicated for improving visualization of
(opacifying) the left ventricular chamber of the heart, as well as
improving the delineation of the endocardial borders (walls).
Imagent is a synthetic product packaged as a dry powder in a
ready-to-use kit. The powder is first reconstituted with water to
form a suspension of microscopic spheres, or
"microspheres." The solution is then injected
intravenously into a patient undergoing echocardiography
(ultrasound of the heart). The use of Imagent in combination with
an ultrasound may better differentiate normal and abnormal heart
structure and function.
Imagent was evaluated in two randomized, controlled, multicenter
trials in subjects with suboptimal echocardiograms. The two studies
included a total of 409 adults with a mean age of 58.9 years. A
suboptimal echocardiogram was defined as two to nine non-visualized
segments (out of 12 segments) in the apical four- and two-chamber
views of the baseline continuous fundamental, two-dimensional
In the trials, all Imagent-treated subjects received a single
intravenous bolus injection of 0.125 mg/kg. Two-dimensional
echocardiography was performed both before and after Imagent
The trials were designed to evaluate Imagent's ability to
improve endocardial border delineation, ejection fraction, and wall
motion scores/measurements. Independent blinded readers (three per
study) scored 16 left ventricular endocardial border segments on a
four-point ordinal scale for delineation and on a six-point scale
for wall motion, in addition to measuring ejection fraction. The 16
segments were in three views: apical four-chamber, apical
two-chamber, and apical long-axis.
In comparing Imagent to baseline, the mean change in endocardial
border delineation score was statistically significant for all
readers for all three views. For ejection fraction, no improvement
over non-contrast studies was observed when ejection fractions
derived from echocardiography were compared to radionuclide
Wall motion was analyzed in a subset of subjects with at least
two adjacent segments non-evaluable in at least two of the three
views on non-contrast imaging. Results showed that treatment with
Imagent converted a baseline non-evaluable image to an evaluable
image in 43 to 79% of the subjects, depending on the reader. In the
converted images, the ability to interpret wall motion (normal vs.
abnormal) improved in 10 to 46% of the subjects, also depending on
the reader; however, improvement in the specific diagnostic
assessments was not established.
The active moiety, the microsphere, consists of two critical
components: perflexane, the gaseous component, and DMPC, the lipid
membrane component. Perflexane is chemically characterized as
n-perfluorohexane, and DMPC is a semi-synthetic (not of animal
origin) phospholipid. After reconstitution and intravenous
injection, Imagent increases the ultrasound reflectivity of blood
in the left ventricle, thereby enhancing the ultrasound signal.
(from Revised Proposed Package Insert)