Shorter duration of anticoagulation as good as standard course for paediatric VTE

A shorter duration of anticoagulant therapy of 6 weeks is as effective in preventing recurrent thrombosis as the conventional 3-month treatment course without increasing the risk of bleeding in young patients aged below 21 years old with acute provoked venous thromboembolism (VTE), according to the Kids-DOTT* trial.  

“When treatment should be stopped is as important as when it should be started. Shorter treatment duration can decrease the risk of adverse events and may be more cost effective,” wrote Drs Benoît Mâsse, Nancy Robitaille, and Jacques Lacroix of Université de Montréal, Montreal, Canada, in a linked editorial. [JAMA 2022;327:124-125] 

“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,” they highlighted.

At 1 year, the cumulative incidence of recurrent VTE — the primary efficacy outcome — was 0.66 percent (95 percent confidence interval [CI], 0–1.95) in patients on anticoagulant for 6 weeks compared with 0.70 percent (95 percent CI, 0–2.07) in patients on the 3-month anticoagulant course. [JAMA 2022;327:129-137]

For the primary safety outcome of clinically relevant bleeding events, the cumulative incidence was 0.65 percent (95 percent CI, 0–1.91) in the 6-week anticoagulant group and 0.70 percent (95 percent CI, 0–2.06) in the 3-month anticoagulant group.

Using a bivariate analytic approach which takes into account the trade-off between the risk of recurrent VTE vs bleeding, the authors demonstrated that the 6-week anticoagulant therapy was noninferior to the 3-month treatment course.

 “The data suggest that 6 weeks of anticoagulant therapy should be considered for standard treatment in children and adolescents after a provoked VTE,” stated Mâsse and co-authors.

The rates of adverse events (AEs) were 26 percent in the 6-week anticoagulant group and 32 percent in the 3-month anticoagulant group — with fever being the most common AE (1.9 percent and 3.4 percent, respectively).

“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 VTE and older patients,” commented Mâsse and co-authors.

The investigator-initiated multinational trial involved 417 patients aged <21 years with acute provoked VTE, of which 297 (median age 8.3 years, 49 percent female) were included in the per-protocol analysis. They were randomized 1:1 to receive anticoagulant therapy for 6 weeks or 3 months. Participants included were without persistent antiphospholipid antibodies and had resolved or non-occlusive thrombi on repeat imaging at 6 weeks.

While the choice of anticoagulant was determined by the treating physician, the predominant anticoagulant used was low-molecular-weight heparin (in 84 percent of patients during the acute treatment period and 86 percent during the subacute period).

“Few patients with cancer or pulmonary embolism were enrolled in the RCT** and patients with active malignancy were excluded,” noted Mâsse and co-authors.

“Caution should be exercised in applying these trial results to such patients,” the researchers advised.

*Kids-DOTT: The Multicenter Evaluation of the Duration of Therapy for Thrombosis in Children

**RCT: Randomized controlled trial