Is low-dose apixaban appropriate treatment for a DVT?
Attached, please see a NEJM study from 2013 that compared apixaban 2.5 mg twice daily with apixaban 5mg twice daily and placebo, for the extended treatment of DVT in patients who were sort of on that border of needing A/C (e.g. not clearly provoked). Unsurprisingly, both apixaban groups had lower rates of recurrent VTE than the placebo group, but I was surprised to see that the rates between the 5mg and 2.5mg groups were so similar.
Figure 2A. Kaplan–Meier Cumulative Event Rates
The study has some limitations: they excluded patients on DAPT, with a Hb below 9, or with a Cr above 2.5. Still, with a number needed to treat of 14, it’s pretty compelling evidence to consider the approach. I generally don’t like half-dosing A/C; I was taught either to treat or not treat, because hedging exposes patients to bleeding risk without giving them the therapeutic benefit of anticoagulation. I still believe that’s true, but, I also imagine this trial might be practice-changing for me, and that I will feel more comfortable utilizing this option of lower dose apixaban going forward, especially for patients with higher bleeding risk.
The number of patients total who were older, had a low body weight, and/or an elevated Cr was limited but not zero. I’m not sure if we’d get the same results if we completely excluded those patients, or if conversely apixaban 2.5mg would be superior if that group was more strongly represented. If any of you know of other literature guiding long-term A/C choices in these equivocal cases, I would appreciate your sharing! And if this study is new to you, too, I hope you enjoy, and please do share your thoughts.
Agnelli G, Buller HR, Cohen A, et al. Apixaban for Extended Treatment of Venous Thromboembolism. New England Journal of Medicine. 2013;368(8):699-708.
