The US Food and Drug Administration has market-approved regadenoson
(Lexiscan), a selective A2A adenosine-receptor agonist, for resting
stress-myocardial perfusion scans, the product's developer and owner
CV Therapeutics and marketer-distributor Astellas Pharma US have
jointly announced [1].

Lexiscan was approved based on two identical phase 3 trials [2] in
which the agent produced perfusion scans of similar quality to those
made using another Astellas product, adenosine injection
(Adenoscan), according to the announcement. Lexiscan is administered
as a non¡Vweight-adjusted rapid bolus, which, published reports
observe, is a less complicated regimen than what is required for
adenosine; it's also expected to have a more favorable side-effect
profile by virtue of its adenosine-receptor selectivity.

CV Therapeutics. CV Therapeutics and Astellas announce FDA approval
for Lexiscan (regadenoson) injection [press release]. April 10,
2008. Available at: http://www.cvt.com/PressRelease.aspx?
releaseID=1128317.
Iskandrian AE, Bateman TM, Belardinelli L, et al. ADVANCE MPI
Investigators. Adenosine versus regadenoson comparative evaluation
in myocardial perfusion imaging: Results of the ADVANCE phase 3
multicenter international trial. J Nucl Cardiol 2007; 14:645-658.
Abstract