Pharmacokinetic-guided Dosing of Emicizumab
- Conditions
- ChildAdultHemophilia A With InhibitorHemophilia A Without InhibitorHemophilia A, SevereAdolescent
- Interventions
- Other: Emicizumab - PK-guided dose reductionOther: Emicizumab - Dose adjustment groupOther: Emicizumab - Dosis continuation group
- Registration Number
- NCT06320626
- Lead Sponsor
- Kathelijn Fischer
- Brief Summary
The goal of this multicentre, prospective, open-label, cross-over clinical study is to determine whether individualized PK-guided dosing of emicizumab is non-inferior to conventional dosing of emicizumab in the prevention of bleeding in congenital haemophilia A patients.
- Detailed Description
Haemophilia A is an X-linked hereditary bleeding disorder resulting from a deficiency or dysfunction of endogenous coagulation factor VIII (FVIII). Persons with haemophilia A (PwHA) suffer from spontaneous or provoked bleeding, predominantly into major joints, which eventually lead to painful and chronic disabling arthropathy. The primary goal in clinical management of haemophilia A is prevention of bleeding by self-administration of FVIII concentrates via intravenous injections.
Prophylaxis with FVIII concentrates has effectively reduced treated bleeds from an annual average of 20-30 to 1-4. However, in approximately 30% of PwHA anti-FVIII antibodies (known as inhibitors) develop that interfere with FVIII replacement therapy. PwHA who develop inhibitors require alternative suboptimal therapy with (costly) bypassing agents (BPA).
The first approved non-factor therapy is the bispecific, FVIII-mimicking antibody, emicizumab (Hemlibra®), which came available in the Netherlands in July 2018. Emicizumab is a humanized, bispecific antibody connecting factor IX and factor X enabling the activation of FX and subsequent thrombin generation. Emicizumab has shown to be highly effective prophylaxis in PwHA by achieving a complete eradication of treated bleeds in around 80% of PwHA (n = 374) during the second 24-week interval of treatment. Furter advantages of emicizumab are the subcutaneous administration and less frequent dosing intervals every 1, 2 or 4 weeks due to a long half-life (t ½: 28 days). Despite many PwHA are candidate for prophylaxis with emicizumab, cost limit widespread access.
Currently, emicizumab is approved by F. Hoffmann-La Roche® with a loading dose of 3 mg/kg/week for four weeks and a maintenance dose of 1.5 mg/kg/week, 3 mg/kg/2 weeks or 6 mg/kg/4 weeks. These dose regimens were based on a pharmacometric approach instead of a dose finding study, and targeted a trough concentration (Ctrough) of 45 µg/ml by using pharmacokinetic (PK)simulations. Meanwhile long-term bleed data from the phase III and IV studies by the pharmaceutical company were included in pharmacokinetic (PK) and pharmacodynamic (PD) modelling studies, and the effective Ctrough was suggested at 30 µg/ml.
Although this Ctrough of 30 µg/ml is substantially lower than the previous Ctrough (45 µg/ml), the dose regimens were not adjusted. Conventional dosing leads to mean concentrations of 55 µg/ml with two thirds of the observations between 40 and 70 µg/ml (i.e., SD of ±15 µg/ml). Emicizumab has been approved based on fixed body-weight-based dosing and therefore the concentration target might have been kept higher to avoid lower effectivity due to inter-patient variability. However, reduced dosing of emicizumab, either by extending the dosing interval or lowering the dose, without sacrificing its efficacy has been reported in small case series.
Therefore, the investigators hypothesized that lower dosing of emicizumab targeted at Ctrough 30 μg/mL, is equally as effective and less costly in preventing bleeds as conventional dosing of emicizumab, and designed the DosEmi study to investigate the hypothesis in a large prospective cohort of adult and paediatric PwHA.
Recruitment & Eligibility
- Status
- RECRUITING
- Sex
- Male
- Target Recruitment
- 95
- Confirmed diagnosis of congenital haemophilia A, with a baseline endogenous FVIII of <6 IU/ml
- Aged > 1 year at inclusion (inclusion of children 1-16 years after favourable interim-analysis see protocol)
- Receiving conventional dosing of emicizumab (6 mg/kg/4 weeks with varying intervals) for a duration of at least 12 months prior to inclusion;
- Having good bleeding control, defined as:
i No spontaneous joint/muscle bleeds in the previous 6 months AND ii A maximum of two treated (traumatic) bleeds in the previous 6 months.
- Willing and able to provide written informed consent, either by the subject or its parents/legal guardian
- Willing to provide bleeding assessment information
- Willing to adhere to the medication regimen
- Acquired haemophilia A
Study & Design
- Study Type
- INTERVENTIONAL
- Study Design
- CROSSOVER
- Arm && Interventions
Group Intervention Description Conventional dosing - open label Emicizumab - PK-guided dose reduction Patients will be followed 6 months retrospectively and 6 months prospectively on conventional dosing. Conventional dosing - open label Emicizumab - Dosis continuation group Patients will be followed 6 months retrospectively and 6 months prospectively on conventional dosing. No intervention adjusted - open label Emicizumab - Dose adjustment group Patients with emicizumab plasma concentration \< 25 μg/mL will be adjusted in dosing regimen according to local protocol. Patients will be followed for selective safety data only. Conventional dosing - open label Emicizumab - Dose adjustment group Patients will be followed 6 months retrospectively and 6 months prospectively on conventional dosing. PK-guided dosing - open label Emicizumab - PK-guided dose reduction Patients with emicizumab concentration of ≥ 40 μg/mL will receive individualized PK-guided dose reduction of emicizumab targeted at a Ctrough of 30μg/mL. Patients will be followed for 12 months on reduced dosing. No intervention continuation - open label Emicizumab - Dosis continuation group Patients with emicizumab concentration of 25-39 μg/mL will continue on their current dose regimen. Patients will be followed for 12 months on current dosing.
- Primary Outcome Measures
Name Time Method Proportion of patients without treated bleeds 12 months Comparison proportion treated bleeds 6 months before (conventional) and after intervention (PK-guided dosing)
- Secondary Outcome Measures
Name Time Method To assess and monitor pain during emicizumab administration 12 months Assessment of pain during emicizumab administration by Visual Analogue Scale (scale 0-10)
To investigate whether direct joint health remains stable measured by physical examination when switching to lower-dosed emicizumab compared to conventional treatment 12 months Joint status will be measured by physical examination (Haemophilia Joint Health Score; HJHS),
To assess the performance of the population PK model 12 months Predictive performance of the MAP Bayesian procedure used for the dose adaptation procedure, defined as % of patients within ±20% of target level/within the target level of 25-39 µg/mL of emicizumab.
To investigate whether Health Related Quality of Life (HR-QoL) are similar in patients receiving conventional dosing compared with PK-guided dosing of emicizumab. 12 months Health related quality of life will be assed with PROMIS instruments (Physical Function/mobility and Pain Interference short forms).
To investigate whether thrombin generation parameters can be used as a pharmacodynamic (PD) biomarker for emicizumab treatment efficacy. 12 months To measure coagulation potential, blood samples will be collected to measure thrombin generation (Peak Height and ETP)
To compare cost-effectiveness between conventional dosing and individualized PK-guided dosing of emicizumab 24 months Direct and indirect medical costs: Direct medical costs are predominantly determined by consumption of emicizumab, additional FVIII, and/or bypassing agents, extracted from the hospital's pharmacy records. These data are highly reliable, as this medication is exclusively distributed by haemophilia treatment centers. Indirect medical costs: are number of (emergency) hospital visits, bleeding related hospital admissions and/or unscheduled surgeries, and days lost from work/school (for patients and/or caregivers).
Proportion of patients without treated bleeds 24 months Comparison proportion without treated bleeds 12 months before (conventional) and after intervention (PK-guided dosing)
Proportion of patients without spontaneous joint- or muscle bleeds 24 months Comparison proportion without spontaneous joint- or muscle bleeds 6 and 12 months before and after intervention.
Annualized bleeding rate (ABR) of treated bleeds, including joint bleeds and sport-induced bleeds 24 months Comparison annualized bleeding rate 6 and 12 months before and after intervention.
To assess the cumulative number of coagulation factor (sc. and/or iv.) of per year. 24 months Assessment of the cumulative number of sc. and/or iv. Injections related to coagulation correction.
To investigate whether direct joint health remains stable measured by ultrasound when switching to lower-dosed emicizumab compared to conventional treatment 12 months Joint status will be measured by ultrasound (if available, according to the HEAD US score).
To investigate if indirect joint health, as measured by biomarkers, remains stable when switching to lower doses of emicizumab compared to conventional treatment. 12 months biomarker assessment for inflammation and joint and cartilage turnover in urine.The biomarkers comprising origin of different joint tissues will be selected and adopted based on the literature on osteoarthritis, which is a rapidly changing area of research.
To investigate whether sports participation are similar in patients receiving conventional dosing compared with PK-guided dosing of emicizumab. 12 months Sports participation (type, duration, frequency) will be assessed with Modifiable Activities Questionnaire (MAQ).
Trial Locations
- Locations (8)
Radboud University Medical Center
🇳🇱Nijmegen, Gelderland, Netherlands
Maastricht University Medical Center
🇳🇱Maastricht, Limburg, Netherlands
HagaZiekenhuis
🇳🇱Den Haag, Zuid-Holland, Netherlands
Amsterdam University Medical Center
🇳🇱Amsterdam, Noord-Holland, Netherlands
University Medical Center Groningen
🇳🇱Groningen, Netherlands
Leids Universitair Medisch Centrum
🇳🇱Leiden, Zuid-Holland, Netherlands
Erasmus University Medical Center
🇳🇱Rotterdam, Zuid-Holland, Netherlands
University Medical Center Utrecht
🇳🇱Utrecht, Netherlands