Evaluation of the Duration of Therapy for Thrombosis in Children
The Kids-DOTT trial is a randomized controlled clinical trial whose primary objective is to evaluate non-inferiority of shortened-duration (6 weeks) versus conventional-duration (3 months) anticoagulation in children with first-episode acute venous thrombosis. The first stage of the trial has consisted of a pilot/feasibility component, which then continues as the definitively-powered trial.
Inclusion Criteria
- Children (birth to <21 years of age) with radiologically-confirmed acute deep venous thrombosis in the past 30 days
- In the opinion of the investigator, the venous thrombosis was a provoked (i.e., non-spontaneous) event (e.g.: hospitalization; Central venous catheterization; infection; dehydration; surgery; trauma; immobility; use of estrogen-containing oral contraceptive pills; flare of autoimmune/rheumatologic condition).
Exclusion Criteria
- Prior episode of VTE
- Malignancy that, in the opinion of the treating oncologist, is not in remission (note: remission may exist on or off anti-neoplastic therapy)
- Systemic lupus erythematosus
- Pulmonary embolism that is not accompanied by DVT or is more proximal than segmental branches of the pulmonary artery
- Use of, or intent to use, thrombolytic therapy
- Chronic anticoagulant at prophylactic dosing is being or will be administered beyond 6 months post VTE diagnosis
- Moderate/severe anticoagulant deficiency (defined by any one of the following):
- protein C <20 IU/dL if patient is ≥3 months of age, or protein C below lower limit of detection if patient is <3 months of age;
- antithrombin <30 IU/dL if patient is ≥3 months of age, or antithrombin below lower limit of detection if patient is <3 months of age;
- protein S (free antigen or activity) <20 IU/dL.
Study sponsor and potential other locations can be found on ClinicalTrials.gov for NCT00687882.
Children (birth to 21 years of age, inclusive) with first-episode venous thrombosis in
association with a reversible clinical trigger (key exclusions: history of cancer; severe
thrombophilia state disclosed) are enrolled and prescribed anticoagulation according to
the clinical standard of care and American College of Physicians (Chest journal) 2012
recommendations. At the 6 week (post-diagnosis) follow-up visit, repeat radiologic
imaging is performed to determine residual thrombus burden and its degree of occlusion.
In addition, those subjects with antiphospholipid antibodies (APA) disclosed at
enrollment will undergo repeat APA testing.
Patients with residual occlusive thrombosis or persistent APA are excluded from
randomization, and followed on parallel cohort arms (observational), with conventional
anticoagulation durations. All other patients are randomized to a total anticoagulant
duration of 6 weeks versus 3 months. Children are followed for primary efficacy endpoints
of symptomatic recurrent venous thromboembolism (VTE) and primary safety endpoints of
clinically-relevant bleeding (major plus clinically-relevant non-major, as per
International Society of Thrombosis and Haemostasis Scientific and Standardization
Committee [Journal of Thrombosis & Haemostasis] 2012 definitions/recommendations).
Children are followed through 2 years (with primary endpoint at 1 year). Those with deep
venous thromboses affecting venous return from the limbs also undergo standardized
post-thrombotic syndrome (PTS) outcome assessment using the Manco-Johnson pediatric PTS
instrument.
The non-inferiority analysis uses a bivariate endpoint approach, modeling the inherent
clinical trade-off between the risks of recurrent VTE and bleeding. The trial will enroll
750 children across 40 participating centers, and allows for a 25% rate of exclusion from
the per-protocol population due to randomization non-eligibility (i.e. parallel cohort),
withdrawal/loss to follow-up, and protocol non-adherence.
A sub-study, completed in late 2013, used investigational dalteparin in lieu of formulary
low molecular weight heparin (typically enoxaparin) in those children who were clinically
prescribed a low molecular weight heparin for sub-acute anticoagulation. The goal of this
sub-study was to report dose-finding and outcomes data in children treated with
dalteparin for VTE. Outcomes in these patients were qualitatively compared with those of
patients who received enoxaparin, warfarin, or other anticoagulants for sub-acute
anticoagulation. This portion of the study was an industry-sponsored
investigator-initiated sub-study with an investigator-held IND. Since the closure of the
sub-study, the overall Kids-DOTT study is no longer conducted under an Investigational
New Drug (IND) application.
Principal aims and hypotheses:
Specific Aim #1: To evaluate the efficacy and safety of shortened-duration (6 weeks
total) versus conventional-duration (3 months total) anticoagulation for first-episode,
provoked, acute venous thrombosis among children in whom thrombus
resolution/non-occlusion (i.e. established blood flow) is evident after the initial 6
weeks of anticoagulant therapy
Hypothesis: Among children with first-episode, provoked, acute venous thrombosis in whom
thrombosis is resolved or non-occlusive at six weeks follow-up, a shortened duration of
anticoagulation (total six weeks; i.e. no further therapy) is non-inferior in efficacy to
the conventional duration (total three months) of anticoagulation with respect to the
risk of symptomatic recurrent VTE at 1 year, and is superior in safety with respect to
the risk of clinically-relevant bleeding.(The hypothesis will also be tested in secondary
analysis at 2 years, using the same efficacy and safety outcomes as for the 1 year
primary analysis.)
Specific Aim #2: To compare the composite efficacy of shortened-duration (6 weeks total)
versus conventional-duration (3 months total) anticoagulation for first-episode,
provoked, acute venous thrombosis among children in whom thrombus
resolution/non-occlusion (i.e., blood flow) is evident after the initial 6 weeks of
anticoagulant therapy.
Hypothesis: Among children with first-episode, provoked, acute venous thrombosis in whom
thrombosis is resolved or non-occlusive at six weeks follow-up, a shortened duration of
anticoagulation (total six weeks; i.e. no further therapy) is non-inferior to the
conventional duration (total three months) of anticoagulation with respect to a composite
efficacy endpoint comprised of the 1-year risk of symptomatic recurrent VTE or PTS. (The
hypothesis will also be tested in secondary analysis at 2 years.)
Specific Aim #3: To determine whether outcomes of first-episode, provoked, acute venous
thrombosis (specifically, with respect to recurrent VTE and PTS) among children treated
with conventional-duration (3 months total) anticoagulation differ between those with and
without thrombus resolution/non-occlusion at 6 weeks.
Hypothesis: Among children with first-episode, provoked, acute venous thrombosis treated
with conventional-duration (3 months total) anticoagulation, the cumulative incidences of
recurrent VTE and PTS are significantly lower among those in whom thrombus
resolution/non-occlusion was, versus was not, evident after the initial 6 weeks of
anticoagulant therapy.
Specific Aim #4: To establish a clinical trial-derived plasma and nucleic acids
biorepository for future proteomic, genomic, and metabolomic investigations of predictors
and modulators of VTE outcomes in children.
Specific Aim #5: To investigate whether duration of anticoagulation (over the range of 3
months to indefinite duration, as determined clinically in routine care) on influences
the risks of symptomatic recurrent VTE and clinically-relevant bleeding among children
with first-episode, provoked, acute venous thrombosis in whom persistent antiphospholipid
antibody (APA) positivity is evident at 6- and 12 -weeks post-diagnosis.
Hypothesis: Among children with first-episode, provoked, acute venous thrombosis in whom
persistent APA positivity is evident at 6- and 12 -weeks post-diagnosis, duration of
anticoagulant therapy is not a predictor of symptomatic recurrent VTE but is directly
related to the risk of clinically-relevant bleeding.
Specific Aim #6 (Exploratory Aim): To evaluate whether the effect of treatment duration
on the risks of symptomatic recurrent VTE and clinically-relevant bleeding in children
with first-episode, provoked, acute venous thrombosis differs substantively between
subgroups defined by type of sub-acute anticoagulant therapy in real-world clinical use
(all prescribed clinically, with the exception of investigational dalteparin, which was
prescribed under an investigator-held IND through December 2013).
Trial PhasePhase III
Trial Typetreatment
Lead OrganizationJohns Hopkins All Children's Hospital
- Primary IDIRB00063928
- Secondary IDsNCI-2019-07436, 1U01HL130048-01A1
- ClinicalTrials.gov IDNCT00687882