Model-informed Dose Optimization for Rivaroxaban in Children With Giant Coronary Artery Aneurysm After Kawasaki Disease

Official title

Rivaroxaban in Chinese Children With Giant Coronary Artery Aneurysm After Kawasaki Disease: a Pilot Study

Overview

Based on a population pharmacokinetic model-based dose optimization study, a 15 mg-equivalent, age-, and bodyweight-adjusted dosing regimen for Chinese children with giant coronary artery aneurysms after Kawasaki disease was proposed. This single-center, single-arm, pilot study aims to evaluate the feasibility of the 15 mg-equivalent dosing regimen within a limited sample size. Patients will be followed for more than 6 months. Clinical outcomes, including coronary artery thrombosis, major adverse cardiovascular events, and bleeding events, will be recorded. Rivaroxaban levels will be measured to assess the robustness of the model-informed dose optimization.

Detailed description

Giant coronary artery aneurysm (GCAA) is a rare but severe cardiac complication of Kawasaki disease (KD). Due to the abnormal blood rheology and the hyper-inflammatory response accompanied by thrombocytosis during the acute phase, patients with GCAA are at high risk of coronary artery thrombosis and major adverse cardiovascular events.In such instances, lifelong antiplatelet (aspirin or clopidogrel) and anticoagulant therapy (warfarin or low molecular weight heparin, LMWH) may become necessary.

In 2022, two compounds, the direct activated Factor X (FXa) inhibitor rivaroxaban was approved by international regulatory agencies for two specific pediatric indications, supported by pharmacometrics models. For instance, a dosing regimen matching exposures of 20 mg daily in adults (the 20 mg-equivalent dosing regimen) is indicated for children under 18 years with venous thromboembolism (VTE). Secondly, a dosing regimen matching exposures of 10 mg daily in adults (the 10 mg-equivalent dosing regimen) is indicated for post-Fontan patients aged two years or older, as shown in the UNIVERSE study, which compared rivaroxaban to aspirin. However, no trials have yet compared rivaroxaban with warfarin/LMWH in pediatric patients with GCAA after KD.

Inter-ethnic population pharmacokinetic (PPK) analyses have suggested that Asian patients may require a lower dosage of rivaroxaban, consistent with the findings from the J-ROCKET trail in Japanese adults. Accordingly, the maximum dosage for Japanese children with VTE (≥ 50 kg) has reduced from 20 mg q24h (every 24 hours) to 15 mg q24h. However, reports on rivaroxaban use in pediatric patients with GCAA after KD, especially in those from Asian countries, remains limited. Its application is more challenging due to (i) increased bleeding risk from concomitant antiplatelet drug use; (ii) the predominance of younger patients (typically \< 3 years) with variability in hepatic and renal function, as well as growth and development.3 Given the low incidence of GCAA, quantitative pharmacometrics is a highly promising approach for precision dosing of rivaroxaban in these patients.

Therefore, the investigators retrospectively collected the clinical experience of rivaroxaban off-label use in Chinese pediatric patients with GCAA after KD from 2023.1 to 2023.12. With clinical evidence and model-extrapolation, the investigators conducted a quantitative pharmacometrics model-based dose optimization study and proposed a 15 mg-equivalent dosing regimen for thromboprophylaxis in Chinese children with GCAA after KD, those who require dual antithrombotic therapy.

This pilot study aims to assess the potential of rivaroxaban for thromboprophylaxis in pediatric patients with KD after GCAA. Specifically, this study seeks to: (ⅰ) preliminarily evaluate the feasibility, efficacy and safety of the 15 mg-equivalent dosing regimen in target population, (ii) provide pharmacokinetic (PK)/pharmacodynamic (PD) data on rivaroxaban in Chinese children.

Interventions

• Drug Rivaroxaban (Xarelto)
  Administered in an age- and bodyweight-adjusted, 15 mg-equivalent dose regimen proposed by model-informed dose optimization study

Primary outcome measures

• Occurrence of new thrombosis in coronary arteries [Time frame: From enrollment to the 6th month after treatment]
• Composite of Major bleeding or Clinically relevant non-major bleeding event [Time frame: From enrollment to the 6th month after treatment]

Secondary outcome measures (3)

• Occurrence of major adverse cardiovascular event [Time frame: From enrollment to the 6th month after treatment]
• Any adverse events [Time frame: From enrollment to the 6th month after treatment]
• Any dose adjustments for rivaroxaban [Time frame: From enrollment to the 6th month after treatment]

Eligibility criteria

Inclusion criteria

• Giant coronary artery aneurysm(s) in any coronary artery after acute stage of Kawasaki disease. Giant coronary artery aneurysm(s) should be confirmed by two-dimensional echocardiography and meet the diagnostic criteria of Z-score ≥10 or coronary artery internal diameter ≥8mm;
• Anticoagulant with antiplatelet drug therapy for anti-thromboprophylaxis is recommended for the next 6 months;
• Participant should be able to tolerate oral feeding, nasogastric or gastric feeding;
• Children aged 1 Month to<18 years, bodyweight ≥ 2600g.

Exclusion criteria

• Active bleeding or bleeding risk contraindicating anticoagulant therapy
• With history of venous thromboembolism or risk factors related with venous thromboembolism, like congenital heart disease, carcinoma, central venous catheter or long-term immobilization.
• Hypersensitivity or any other contraindications listed in the local labeling for the comparator treatment or experimental treatment
• An eGFR <30 mL/min/1.73 m2 (For children younger than 1 year, serum creatinine results above 97.5th percentile)
• Platelet count < 100 x 109/L
• Hepatic disease which is associated with either: coagulopathy leading to a clinically relevant bleeding risk, or alanine aminotransferase > 5x ULN or total bilirubin > 2x ULN with direct bilirubin > 20% of the total
• Sustained uncontrolled hypertension defined as systolic and/or diastolic blood pressure >95 th age percentile
• Concomitant use of strong inhibitors of both CYP3A4 and P-glycoprotein, including but not limited to all human immunodeficiency virus protease inhibitors and the following azole-antimycotics agents: ketoconazole, itraconazole, voriconazole, posaconazole, if used systemically (fluconazole is allowed)
• Concomitant use of strong inducers of CYP3A4, including but not limited to rifampicin, rifabutin, phenobarbital, phenytoin and carbamazepine
• Hypersensitivity or any other contraindications listed in the local labeling for the comparator treatment or experimental treatment
• Inability to cooperate with the study procedures and follow-up visits
• Refuse to provide informed consent

eGFR, estimated glomerular filtration rate; ULN, upper level of normal; TB, total bilirubin (TB); CYP3A4, cytochrome P450 isoenzyme 3A4

Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.

Healthy volunteers: No

Study design

Allocation

N/A

Model

Single group

Masking

Open label

Primary purpose

Prevention

Study locations

China · 1 center

• Children's Hospital of Fudan University — Shanghai

Identifiers

NCT: NCT06978439 · RIVA-KD-pilot

Primary sources (government registries)

• ClinicalTrials.gov (US NIH)

View this study on ClinicalTrials.gov ↗