ORLANDO – Idarucizumab, the reversal agent for the anticoagulant dabigatran, appeared as effective in quickly reversing dabigatran’s effects in patients with severe renal dysfunction as in patients with normally working kidneys, in a post hoc analysis of data collected in the drug’s pivotal trial.
A standard dose of idarucizumab “works just as well in patients with bad kidney function as it does in patients with preserved kidney function,” John W. Eikelboom, MD, said at the annual meeting of the American College of Cardiology. “The time to cessation of bleeding and the degree of normal hemostasis achieved was consistent” across the entire range of renal function examined, from severe renal dysfunction, with a creatinine clearance rate of less than 30 mL/min, to normal function, with an estimated rate of 80 mL/min or greater.
The ability of idarucizumab (Praxbind), conditionally approved by the Food and Drug Administration in 2015 and then fully approved in April 2018, to work in patients with impaired renal function has been an open question and concern because dabigatran (Pradaxa) is excreted renally, so it builds to unusually high levels in patients with poor kidney function. “Plasma dabigatran levels might be sky high, so a standard dose of idarucizumab might not work. That’s been a fear of clinicians,” explained Dr. Eikelboom, a hematologist at McMaster University in Hamilton, Ont.
To examine whether idarucizumab’s activity varied by renal function he used data from the patients enrolled in the RE-VERSE AD (Reversal Effects of Idarucizumab on Active Dabigatran) study, the pivotal dataset that led to idarucizumab’s U.S. approval. The new, post hoc analysis divided patients into four subgroups based on their kidney function, and focused on the 489 patients for whom renal data were available out of the 503 patients in the study (N Engl J Med. 2017 Aug 3;377:431-41). The subgroups included 91 patients with severe dysfunction with a creatinine clearance rate of less than 30 mL/min; 127 with moderate dysfunction and a clearance rate of 30-49 mL/min; 163 with mild dysfunction and a clearance rate of 50-79 mL/min; and 108 with normal function and a creatinine clearance of at least 80 mL/min.
Patients in the subgroup with severe renal dysfunction had the worst clinical profile overall, and as predicted, had a markedly elevated average plasma level of dabigatran, 231 ng/mL, nearly five times higher than the 47-ng/mL average level in patients with normal renal function.
The ability of a single, standard dose of idarucizumab to reverse the anticoagulant effects of dabigatran were essentially identical across the four strata of renal activity, with 98% of patients in both the severely impaired subgroup and the normal subgroup having 100% reversal within 4 hours of treatment, Dr. Eikelboom reported. Every patient included in the analysis had more than 50% reversal.
The study followed patients to 12-24 hours after they received idarucizumab, and 55% of patients with severe renal dysfunction showed a plasma dabigatran level that crept back toward a clinically meaningful level and so might need a second idarucizumab dose. In contrast, this happened in 8% of patients with normal renal function.