Pediatric Kidney Transplant RecipientsPhase 4OPTI-TREXNCT05672550
Dose-adjustment of Enoxaparin by a Bayesian Pharmacological Approach in Pediatric Kidney Transplant Recipients (OPTI-TREX)
A Phase 4 study testing Bayesian based dose adjustment of enoxaparin and Usual dose adjustment of enoxaparin in people with Pediatric Kidney Transplant Recipients, run by Assistance Publique - Hôpitaux de Paris at 10 sites in France.
Trial 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. Read more about this study
- Who is it for?
- Ages 2 to 20 years
- Conditions the study is for
- Pediatric Kidney Transplant Recipients
- What is being tested?
- Bayesian based dose adjustment of enoxaparin and Usual dose adjustment of enoxaparin
- Type of treatment
- Injection or infusion
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 50 participants
- Where
- 10 sitesFrance
- Study dates
- 28 Jun 2023to 26 Feb 2026
- Phase
- Phase 4
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 2 to 20 years
- All sexes
- No healthy volunteers
- Child, Adult
Who may be able to join
- Pediatric renal transplant recipients
- Aged ≥ 2 years and ≤18 years
- 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.
- Informed consent form signed by the legal guardian(s)
- Affiliated to a health insurance system, including AME
Who cannot join
- Per-transplant technical surgical problems
- Pre-inclusion allograft thrombosis (before randomization and enoxaparin administration)
- Peri-operative thrombosis or uncontrolled bleeding (before randomization and enoxaparin administration)
- Peri-operative hemodynamic instability
- Medical history of heparin-induced thrombocytopenia
- Allergic reaction to enoxaparin or excipients
Show all 9Show fewer
- Pregnancy
- LMWH (Low molecular weight heparins) prophylactic before transplant
- UFH (unfractionated heparin) treatment during renal transplantation with an anti-Xa level detectable 4-6h post administration
Trial locations and contacts
10 sites in 1 country.
10 sites in 1 country
France10 sites
Hôpital Pellegrin
Bordeaux, 33000
CHU Félix Guyon
La Réunion
Hôpital Mère Enfant
Lyon
Hôpital de la Villeneuve
Montpellier
Hôtel Dieu
Nantes
Hôpital Necker Enfants Malades
Paris, 75015
Hôpital Robert Debré
Paris, 75019
Hôpital Necker - Enfants malades
Paris, Île-de-France Region, 75015
Hôpital de Hautepierre
Strasbourg
Hôpital des Enfants
Toulouse
About this study
Official title: Dose-adjustment of Enoxaparin by a Bayesian Pharmacological Approach in Pediatric Kidney Transplant Recipients
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.
Read the 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.
- Conditions
- Pediatric Kidney Transplant Recipients
- Being tested
- Bayesian based dose adjustment of enoxaparin, Usual dose adjustment of enoxaparin
- Keywords
- Kidney transplantation, Children, Enoxaparin, Bayesian based dose, Anti-Xa activity, allograft thrombosis
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Bayesian based dose adjustment of enoxaparinDrug
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.
Usual dose adjustment of enoxaparinDrug
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.
| Study group | Role | What they receive |
|---|---|---|
| Bayesian based dose adjustment | Experimental | Optimization of the enoxaparin dose using a bayesian program in order to prevent patients from complications due to the renal transplantation.
A first recommended dose of enoxaparin (50 IU/kg) is administered subcutaneously during transplantation or within the first 24 hours.
Then, in the experimental group, the dose is adjusted following a bayesian program integrated in the electronic Case Report Form which is based on each patient's data as the Anti-Xa activity Receives: Drug: Bayesian based dose adjustment of enoxaparin |
| Treatment as usual (empirical dose adjustment) | Active comparator | Anti-Xa activity is measured and twice-daily enoxaparin empirical dose-adjustment is performed according to the usual practices in the investigating centers Receives: Drug: Usual dose adjustment of enoxaparin |
What is being measured
The primary outcome is the main question the study is designed to answer.
Anti-Xa activity within the target range
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).
Measured: At 28-30 hours after initiation of treatment
Secondary outcomes (12)
Anti-Xa outcome measurement ≥0.3 IU/ml and ≤0.6 IU/mL
Anti-Xa outcome measurement is defined as: Anti-Xa activity 4-6 hours after the first enoxaparin injection on day 2
Measured: At 28-30 hours after initiation of treatment
Difference between the Anti-Xa outcome measurement and the middle of the target range
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
Measured: At 28-30 hours after initiation of treatment
Absolute difference between the Anti-Xa outcome measurement and the middle of the target range
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
Measured: At 28-30 hours after initiation of treatment
Precision of Anti-Xa outcome measurement to reach the middle of the target range
Precision (Root Mean square Error) - middle of the target range = 0.4 UI/mL
Measured: At 28-30 hours after initiation of treatment
Anti-Xa activity within the target range 4-6 hours after the 2nd enoxaparin injection
Anti-Xa activity ≥0.3 IU/mL and ≤0.5 IU/mL
Measured: From 28-30 hours to 7 days after initiation of treatment
Anti-Xa activity ≥0.3 IU/mL and ≤0.6 IU/mL 4-6 hours after the 2nd enoxaparin injection
Anti-Xa activity ≥0.3 IU/mL and ≤0.6 IU/mL
Measured: From 28-30 hours to 7 days after initiation of treatment
Time to achieve a target Anti-Xa activity (0.3-0.5 IU/mL)
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.
Measured: From 28-30 hours to 7 days after initiation of treatment
Percentage of time within the target range
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
Measured: From 28-30 hours to 7 days after initiation of treatment
Graft thrombosis
Graft thrombosis : assessed by allograft ultrasound
Measured: Up to 30 days
Enoxaparin-related side effects
Enoxaparin-related side effects during the first postoperative month: bleeding (all localisations), graft hematoma (presence/absence): assessed by ultrasound
Measured: Up to 30 days
Allograft bleeding
Allograft bleeding: bleeding with post-operative transfusion
Measured: Up to 30 days
Enoxaparin induced thrombopenia
Thrombopenia
Measured: Up to 30 days
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted5 Jan 2023
- Study start28 Jun 2023
- Primary completion13 Aug 2025
- Study completion26 Feb 2026
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Pediatric Kidney Transplant RecipientsStudies of the same condition, open and under way.
- More trials run by Assistance Publique - Hôpitaux de ParisThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 4
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Enrolment
- 50 participants (actual)
Sponsor and investigators
- Lead sponsor
- Assistance Publique - Hôpitaux de Paris
- Sponsor type
- University, hospital or other
- Collaborators
- URC-CIC Paris Descartes Necker Cochin
- Responsible party
- Sponsor
- Investigators
- Olivia BOYER, Pr, Principal investigator, Assistance Publique - Hôpitaux de Paris
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05672550
- Sponsor's protocol ID
- APHP180617
- Other IDs
- 2021-000099-12
- Acronym
- OPTI-TREX
- Status last verified
- Apr 2026
- First submitted
- 3 Jan 2023
- Last updated
- 7 Jul 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 7 Jul 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Dose-adjustment of Enoxaparin by a Bayesian Pharmacological Approach in Pediatric Kidney Transplant Recipients
- ClinicalTrials.gov ID
- NCT05672550
- Acronym / sponsor ID
- OPTI-TREX / APHP180617
- Conditions
- Pediatric Kidney Transplant Recipients
- Keywords
- Kidney transplantation, Children, Enoxaparin, Bayesian based dose, Anti-Xa activity, allograft thrombosis
- Phase
- Phase 4
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 50 participants (actual)
- Lead sponsor
- Assistance Publique - Hôpitaux de ParisUniversity, hospital or other
- Collaborators
- URC-CIC Paris Descartes Necker Cochin
- Study start
- 28 Jun 2023 (actual)
- Primary completion
- 13 Aug 2025 (actual)
- Study completion
- 26 Feb 2026 (actual)
- First posted
- 5 Jan 2023 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Bayesian based dose adjustment | Experimental | Drug: Bayesian based dose adjustment of enoxaparinOptimization of the enoxaparin dose using a bayesian program in order to prevent patients from complications due to the renal transplantation. A first recommended dose of enoxaparin (50 IU/kg) is administered subcutaneously during transplantation or within the first 24 hours. Then, in the experimental group, the dose is adjusted following a bayesian program integrated in the electronic Case Report Form which is based on each patient's data as the Anti-Xa activity |
| Treatment as usual (empirical dose adjustment) | Active comparator | Drug: Usual dose adjustment of enoxaparinAnti-Xa activity is measured and twice-daily enoxaparin empirical dose-adjustment is performed according to the usual practices in the investigating centers |
Who may qualify
- Ages
- 2 to 20 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Child, Adult
Key inclusion criteria (5 listed)
- Pediatric renal transplant recipients
- Aged ≥ 2 years and ≤18 years
- 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.
- Informed consent form signed by the legal guardian(s)
- Affiliated to a health insurance system, including AME
Key exclusion criteria (9 listed)
- Per-transplant technical surgical problems
- Pre-inclusion allograft thrombosis (before randomization and enoxaparin administration)
- Peri-operative thrombosis or uncontrolled bleeding (before randomization and enoxaparin administration)
- Peri-operative hemodynamic instability
- Medical history of heparin-induced thrombocytopenia
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Bayesian based dose adjustment of enoxaparinA 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. | Drug | Bayesian based dose adjustment |
| Usual dose adjustment of enoxaparinA 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. | Drug | Treatment as usual (empirical dose adjustment) |
Primary outcome
Anti-Xa activity within the target range
Time frame: 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).
12 secondary outcomes
Anti-Xa outcome measurement ≥0.3 IU/ml and ≤0.6 IU/mL
Time frame: At 28-30 hours after initiation of treatment
Difference between the Anti-Xa outcome measurement and the middle of the target range
Time frame: At 28-30 hours after initiation of treatment
Absolute difference between the Anti-Xa outcome measurement and the middle of the target range
Time frame: At 28-30 hours after initiation of treatment
Precision of Anti-Xa outcome measurement to reach the middle of the target range
Time frame: At 28-30 hours after initiation of treatment
Anti-Xa activity within the target range 4-6 hours after the 2nd enoxaparin injection
Time frame: From 28-30 hours to 7 days after initiation of treatment
Anti-Xa activity ≥0.3 IU/mL and ≤0.6 IU/mL 4-6 hours after the 2nd enoxaparin injection
Time frame: From 28-30 hours to 7 days after initiation of treatment
Time to achieve a target Anti-Xa activity (0.3-0.5 IU/mL)
Time frame: From 28-30 hours to 7 days after initiation of treatment
Percentage of time within the target range
Time frame: From 28-30 hours to 7 days after initiation of treatment
Graft thrombosis
Time frame: Up to 30 days
Enoxaparin-related side effects
Time frame: Up to 30 days
Allograft bleeding
Time frame: Up to 30 days
Enoxaparin induced thrombopenia
Time frame: Up to 30 days
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 7 Jul 2026.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Olivia BOYER, Pr principal investigator
Assistance Publique - Hôpitaux de Paris
10 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 4 study testing Bayesian based dose adjustment of enoxaparin and Usual dose adjustment of enoxaparin in people with Pediatric Kidney Transplant Recipients, run by Assistance Publique - Hôpitaux de Paris at 10 sites in France.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 5 inclusion and 9 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 7 Jul 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 10 sites in France. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 4 studies take place after a treatment is approved, to learn more about its long-term benefits and risks in everyday use.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Anti-Xa activity within the target range (time frame: At 28-30 hours after initiation of treatment). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 7 Jul 2026.