Shorter Course of Anticoagulant Therapy Adequate for Provoked VTE in Children

By Reuters Staff

January 12, 2022

NEW YORK (Reuters Health) - For children with acute provoked venous thromboembolism (VTE), six weeks of anticoagulant therapy is as effective as a three-month course of anticoagulant therapy, results of a new clinical trial suggest.

"When treatment should be stopped is as important as when it should be started," say the authors of an editorial published with the study in JAMA.

"The findings suggest that anticoagulant therapy could be stopped sooner than currently recommended and that doing so is likely to be as safe as longer treatment. Quality of life may be improved in many children by decreasing the duration of subcutaneous injections," write Dr. Jacques Lacroix of the University of Montreal, in Canada, and colleagues.

Among patients younger than 21 years, the optimal duration of anticoagulant therapy for VTE is unknown. However, the standard of care for provoked VTE (that is, VTE temporally associated with a prothrombotic clinical risk factor) has been a three-month course of anticoagulant therapy, as recommended for adults.

The Kids-DOTT trial was a noninferiority randomized trial that compared the efficacy and safety of six weeks versus three months of anticoagulant therapy to prevent recurrent VTE in 417 patients younger than age 21 years (median age, 8.3 years) who experienced an acute provoked VTE.

Provoking factors included recent hospitalization, traumatic injury, central venous catheterization. The chief exclusion criteria were prior VTE, active malignancy, systemic lupus erythematosus, pulmonary embolism unaccompanied by deep vein thrombosis, thrombolytic therapy for the index VTE, and clinically significant deficiencies of natural anticoagulants (protein C, protein S, antithrombin).

The primary efficacy and safety endpoints were symptomatic recurrent VTE and clinically relevant bleeding events within one year by blinded assessment.

The cumulative incidence of symptomatic recurrent VTE was 0.66% with six weeks of treatment and 0.70% with three months of treatment and clinically relevant bleeding events within one year were 0.65% and 0.70%, respectively.

"Based on absolute risk differences in recurrent venous thromboembolism and clinically relevant bleeding events between groups, noninferiority was demonstrated," report Dr. Neil Goldenberg of the Institute for Clinical and Translational Research, Johns Hopkins All Children's Hospital in St. Petersburg, Florida, and colleagues.

Adverse events occurred in 26% of patients in the six-week group and in 32% of patients in the three-month group; fever was the most common adverse event (1.9% and 3.4%, respectively).

This study shows that a "short period of anticoagulant therapy of six weeks can effectively and safely prevent recurrent thrombosis," the editorial writers say.

"Given that the study was conducted at 42 centers in five countries over 13 years, it is unlikely to be repeated. Although the data reported by Goldenberg et al are compelling enough that some practitioners may want to apply them immediately, the results should be applied judiciously and not be extrapolated to patients with unprovoked venous thromboembolism and older patients," they caution.

The Kids-DOTT study was funded by grants from the National Heart, Lung, and Blood Institute; the Bridge Award from the American Society of Hematology; the Thrombosis Studies Award from the Hemophilia and Thrombosis Research Society of North America; an investigator-initiated studies award from Eisai Inc; and an institutional research award from the Johns Hopkins All Children's Foundation. Dr. Goldenberg reported receiving personal fees from Anthos, Bristol Myers Squibb, Bayer, Daiichi-Sankyo, Pfizer and Novartis.

SOURCE: https://bit.ly/3HWoIe8 and https://bit.ly/3rbJZcS JAMA, online January 11, 2022.

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