Summary
Tecarfarin is a novel vitamin K antagonist that is metabolised by carboxyl estererase,
thereby eliminating the variability associated with cytochrome-mediated metabolism.
EmbraceAC was designed to compare the quality of anticoagulation with tecarfarin and
warfarin as determined by time in therapeutic range (TTR). In this phase 2/3 randomised
and blinded trial, 607 patients with indications for chronic anticoagulation were
assigned to warfarin (n=304) or tecarfarin (n=303). Dosing of study drugs was managed
by a centralised dose control centre, which had access to genotyping. The primary
analysis tested superiority of tecarfarin over warfarin for TTR. Patients were recruited
between May 12, 2008 and May 12, 2009. TTR with tecarfarin and warfarin were similar
(72.3% and 71.5%, respectively; p=0.51). In those taking CYP2C9 interacting drugs,
the TTR on tecarfarin (n=92) was similar to that on warfarin (n=87, 72.2% and 69.9%,
respectively; p=0.15). In patients with mechanical heart valves, the TTR of tecarfarin
(n=42) was similar to that of warfarin (n=42, 68.4% and 66.3%, respectively; p=0.51).
The same was true for the TTR in patients with any CYP2C9 variant allele and on CYP2C9-interacting
drugs (tecarfarin, n=24, 76.5% vs warfarin, n=31, 69.5%; p=0.09). There was no difference
in thromboembolic or bleeding events. In conclusion, superiority of tecarfarin over
warfarin for TTR was not demonstrated. The TTR with tecarfarin was similar to that
with well-controlled warfarin and tecarfarin appeared to be safe and well tolerated
with few major bleeding and no thrombotic events. Favourable trends in certain subpopulations
make tecarfarin a promising oral anticoagulant that deserves further study.
Supplementary Material to this article is available online at www.thrombosis-online.com.
Keywords
Anticoagulation - warfarin - tecarfarin - CYP2C9