Pediatric Kidney Transplant Recipients
Conditions
Keywords
Kidney transplantation, Children, Enoxaparin, Bayesian based dose, Anti-Xa activity, allograft thrombosis
Brief summary
Allograft vascular thrombosis is a devastating complication in kidney transplantation in adults and older children. Though uncommon, it is often irreversible and represents the main cause of graft loss within after kidney transplantation in adults and in the first post-operative year in children. Since allograft thrombosis is usually observed in the first 48h post-operatively, the need to promptly achieve appropriate anticoagulation in at-risk patients is of utmost importance. However, no consensus exists regarding the optimal prophylaxis in the peri-transplant period and the following dose-adjustment, and practices are highly heterogeneous among centers. Moreover, the therapeutic target is very narrow and antithrombotic agents may conversely increase the risk of allograft hematoma. Enoxaparin is a low molecular weight heparin commonly used in this context, but off-label in children. Therapeutic ranges are based on anti-Xa levels 4 to 6 hours following injection and extrapolated from adults although evidences suggest that such extrapolation may be inappropriate in many circumstances. The current pediatric practice of dose adjustment to achieve and maintain a target anti-Xa range is empirical and dependent on the physician. The aim of the proposed clinical trial is to assess the efficacy/safety profile of this bayesian-based dose optimization in the clinical setting, as compared to the current practices of empirical adjustment. This should greatly improve the personalized management of renal transplanted children, a subset of patients with singular renal function and little-investigated pharmacokinetics and help standardizing and rationalizing practices.
Detailed description
The investigators will compare the efficacy of the Bayesian based dose versus the dose determined in a usual empirical way based on each physician's experience. The primary endpoint is the Anti-Xa activity within the target range 28 to 30 hours after initiation of the treatment. This is an open labelled randomized clinical trial. The randomization will proceed during the inclusion visit by the local pediatric nephrologist or intensivist just before the first enoxaparin injection, administered within 24 hours post-transplantation. The investigators will conduct a national multicentric study with 9 inclusion centers which are all nephrology units specialized in renal transplantation.
Interventions
DRUGBayesian based dose adjustment of enoxaparin
A first recommended dose of enoxaparin 50 IU/kg subcutaneously is administered during transplantation or within the first 24 hours. Then a Bayesian estimate of individual pharmacokinetics is performed to adapt the next twice daily (Hour 12;Hour 24) enoxaparin dose until achievement of the target on two consecutive measurements. Then anti-Xa activity will be evaluated once a day until day 7.
DRUGUsual dose adjustment of enoxaparin
A first recommended dose of enoxaparin 50 IU/kg is administered during transplantation or within the first 24 hours. Then anti-Xa activity is measured and twice-daily (hour 12 ; hour 24) enoxaparin empirical dose-adjustment is performed according to the usual practices in the investigating centers to target.
Sponsors
Assistance Publique - Hôpitaux de Paris
URC-CIC Paris Descartes Necker Cochin
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
2 Years to 20 Years
Healthy volunteers
No
Inclusion criteria
1. Pediatric renal transplant recipients 2. Aged ≥ 2 years and ≤18 years 3. With an indication for enoxaparin treatment in the first post-transplant week according to the local transplant team such as inherited or acquired thrombotic disorders (eg. but not exclusive protein C, protein S, and antithrombin III deficiency; factor V Leiden mutation (FV506Q), prothrombin mutation (G20210A), mutation in the MTHFR (methyl Tetra hydro folate reductase) gene (C677T), and antiphospholipid antibodies (anticardiolipin antibodies and lupus anticoagulants), history of thrombosis, donor age \< 2 years, recipient age \< 5 years, cold ischemia time \>24h, multiple renal vessels. 4. Informed consent form signed by the legal guardian(s) 5. Affiliated to a health insurance system, including AME
Exclusion criteria
1. Per-transplant technical surgical problems 2. Pre-inclusion allograft thrombosis (before randomization and enoxaparin administration) 3. Peri-operative thrombosis or uncontrolled bleeding (before randomization and enoxaparin administration) 4. Peri-operative hemodynamic instability 5. Medical history of heparin-induced thrombocytopenia 6. Allergic reaction to enoxaparin or excipients 7. Pregnancy 8. LMWH (Low molecular weight heparins) prophylactic before transplant 9. UFH (unfractionated heparin) treatment during renal transplantation with an anti-Xa level detectable 4-6h post administration
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Anti-Xa activity within the target range | At 28-30 hours after initiation of treatment | Anti-Xa activity within the target range (i.e., success defined by an anti-Xa activity ≥0.3 IU/mL and ≤0.5 IU/mL). |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Anti-Xa outcome measurement ≥0.3 IU/ml and ≤0.6 IU/mL | At 28-30 hours after initiation of treatment | Anti-Xa outcome measurement is defined as: Anti-Xa activity 4-6 hours after the first enoxaparin injection on day 2 |
| Difference between the Anti-Xa outcome measurement and the middle of the target range | At 28-30 hours after initiation of treatment | Anti-Xa outcome measurement is defined as: Anti-Xa activity 4-6 hours after the first enoxaparin injection on day 2- the middle of the target range = 0.4UI/mL |
| Absolute difference between the Anti-Xa outcome measurement and the middle of the target range | At 28-30 hours after initiation of treatment | Anti-Xa outcome measurement is defined as: Anti-Xa activity 4-6 hours after the first enoxaparin injection on day 2 - middle of the target range = 0.4UI/mL |
| Precision of Anti-Xa outcome measurement to reach the middle of the target range | At 28-30 hours after initiation of treatment | Precision (Root Mean square Error) - middle of the target range = 0.4 UI/mL |
| Anti-Xa activity within the target range 4-6 hours after the 2nd enoxaparin injection | From 28-30 hours to 7 days after initiation of treatment | Anti-Xa activity ≥0.3 IU/mL and ≤0.5 IU/mL |
| Anti-Xa activity ≥0.3 IU/mL and ≤0.6 IU/mL 4-6 hours after the 2nd enoxaparin injection | From 28-30 hours to 7 days after initiation of treatment | Anti-Xa activity ≥0.3 IU/mL and ≤0.6 IU/mL |
| Time to achieve a target Anti-Xa activity (0.3-0.5 IU/mL) | From 28-30 hours to 7 days after initiation of treatment | Time will be defined by the delay between date and time of treatment initiation and date and time of anti-Xa activity measurement in the target range. |
| Percentage of time within the target range | From 28-30 hours to 7 days after initiation of treatment | The target range is defined as anti-Xa activity ≥0.3 IU/ml and ≤0.5 IU/mL from treatment initiation to D7 derived with individual predicted concentration time course |
| Graft thrombosis | Up to 30 days | Graft thrombosis : assessed by allograft ultrasound |
| Enoxaparin-related side effects | Up to 30 days | Enoxaparin-related side effects during the first postoperative month: bleeding (all localisations), graft hematoma (presence/absence): assessed by ultrasound |
| Allograft bleeding | Up to 30 days | Allograft bleeding: bleeding with post-operative transfusion |
| Enoxaparin induced thrombopenia | Up to 30 days | Thrombopenia |
Countries
France
Contacts
PRINCIPAL_INVESTIGATOROlivia BOYER, Pr
Assistance Publique - Hôpitaux de Paris
Outcome results
None listed