CLINICAL NEWS
and overall survival were all improved among patients with severe
ADAMTS13 deficiency compared
with patients without this deficiency
(TABLE 2).
Nearly all patients with severe
ADAMTS13 deficiency received
therapeutic plasma exchange (TPE),
compared with those without
severe deficiency (95.6% vs. 38.2%,
respectively; p<0.0001). Use of
TPE in patients with ADAMTS13
activity >10 percent, however, varied
significantly across the institutions
included in the study (range = 13.263.8%; p<0.0001).
However, this variation in the
use of TPE in TMA patients without
severe ADAMTS13 deficiency was
not associated with a difference in
mortality (60% in patients with ADAMTS13 ≤10% and 96% for patients
with ADAMTS13 >10%; p=0.98).
There are a number of limitations inherent to this study, given
the nature of the retrospective re-
view, Dr. Benapudi and co-authors
noted. “For example, we were not
able to reliably document TTP
relapses that may have been treated
at institutions outside of the consortium. … Also, suspected cases
of TTP for which an ADAMTS13
assay was not sent would not have
been captured in the dataset.”
“Our work underscores the need
for a clinical scoring tool to assist in
the rapid identification of patients
with severe ADAMTS13 deficiency
so that these cases can quickly move
on to receive life-saving care,” the
authors concluded.
REFERENCES
Hassan S, Westwood J, Ellis D, et al. The utility of
ADAMTS13 in differentiating TTP from other acute
thrombotic microangiopathies: results from the UK TTP
Registry. Br J Haematol. 2015 September 11. [Epub ahead
of print]
Bendapudi PK, Li A, Hamdan A, et al. Impact of severe
ADAMTS13 deficiency on clinical presentation and
outcomes in patients with thrombotic microangiopathies:
the experience of the Harvard TMA Research Collaborative.
Br J Haematol. 2015 August 28. [Epub ahead of print]
Andexanet Alfa Reverses Anticoagulant Activity
of Apixaban, Rivaroxaban
The investigational drug andexanet alfa is
a reversal agent designed to neutralize the
anticoagulant effects of both direct and indirect factor Xa inhibitors. With an increasing
number of patients receiving factor Xa inhibitors, such as rivaroxaban, apixaban, and
edoxaban, the need for reversal agents is high
– particularly among those who experience
bleeding or require emergency surgery.
To evaluate the safety and efficacy of
andexanet alfa, Deborah M. Siegal, MD, of
McMaster University in Hamilton, Canada,
and colleagues conducted two parallel, randomized, double-blind, placebo-controlled
studies in healthy, older patients receiving
apixaban (the ANNEXA-A study) or rivaroxaban (the ANNEXA-R study). The results of
the study were published in The New England
Journal of Medicine.
“The ANNEXA-A and ANNEXA-R studies provide important information about
the ability of andexanet alfa to reverse the
anticoagulant effects of rivaroxaban and
apixaban as measured by laboratory tests in
healthy volunteer subjects,” Dr. Siegal told
ASH Clinical News.
The study was conducted at two sites in
Arizona and California between March 2014
and May 2015 and included 145 patients
with a mean age of 57.9 years (range = 50-75
years). The study’s primary outcome was
mean W&6V