Wiskott-Aldrich Syndrome (WAS)

Active Ingredient: Etuvetidigene autotemcel

Indication for Etuvetidigene autotemcel

Population group: only infants (40 days - 1 year old) , children (1 year - 12 years old) , adolescents (12 years - 18 years old) , adults (18 - 65 years old)
Therapeutic intent: Curative procedure

Etuvetidigene autotemcel is indicated for the treatment of patients aged 6 months and older with Wiskott-Aldrich Syndrome (WAS) who have a mutation in the WAS gene for whom haematopoietic stem cell (HSC) transplantation is appropriate and no suitable human leukocyte antigen (HLA)-matched related haematopoietic stem cell donor is available.

For this indication, competent medicine agencies globally authorize below treatments:

7 × 10⁶ CD34+ cells/kg of body weight once, minimum recommended dose

For:

Dosage regimens

In case that patient age in months is ≥ 6

Intravenous, 7,000,000 cells etuvetidigene autotemcel, one dose.

Detailed description

Etuvetidigene autotemcel must be administered in a qualified treatment centre by a physician with experience in haematopoietic stem cell transplantation (HSCT) and trained for administration and management of patients treated with the medicinal product.

Before mobilisation, apheresis and reduced intensity conditioning are initiated, it must be confirmed that haematopoietic stem cell (HSC) transplantation is appropriate for the patient.

Physicians should refer to the SmPCs of medicinal products used for pre-treatment, peripheral blood mobilisation and conditioning to ensure appropriate guidance to the patient.

Posology

Etuvetidigene autotemcel is intended for autologous use only and should be administered once.

Treatment consists of a single dose for infusion containing a dispersion of viable CD34+ cells in one or more infusion bags.

The dose of etuvetidigene autotemcel to be administered is defined based on the patient's body weight at the time of infusion.

The minimum recommended dose is 7 × 106 CD34+ cells/kg of body weight.

The maximum volume of etuvetidigene autotemcel to be administered should remain <20% of the patient's estimated plasma volume.

Pre-treatment and conditioning

The treating physician should confirm that autologous HSPC gene therapy administration is clinically appropriate for the patient before rituximab and conditioning is initiated.

Conditioning should not begin until the complete set of infusion bag(s) constituting the dose of etuvetidigene autotemcel has been received and stored at the administration site, and the availability of the back-up collection is confirmed.

Peripheral blood mobilisation and apheresis

The autologous CD34+ cells are isolated from mobilised peripheral blood. This is achieved by apheresis procedure(s) following peripheral blood mobilisation.

To obtain CD34+ cells for medicinal product manufacturing and for autologous back up, patients are required to undergo haematopoietic stem and progenitor cell (HSPC) mobilisation with granulocyte-colony stimulation factor (G-CSF) and plerixafor followed by leukapheresis.

A total HSPC collection target of 40 × 106 CD34+ cells/kg is recommended for medicinal product manufacture. In addition to this, at least 3 × 106 CD34+ cells/kg should be collected as autologous back-up The back-up cells may be harvested either through mobilised peripheral blood apheresis or bone marrow harvest.

Pre-treatment with Rituximab and reduced intensity conditioning regimen

Busulfan and fludarabine are the recommended conditioning medicinal products.

 Days
before the
treatment
infusion
Dosing regimenDose
RituximabDay-22
(+/- 1 day)
The infusion of a single dose of
IV Rituximab, a monoclonal
antibody anti-CD20, is
recommended at Day –22 (+/- 1
day) before the infusion of
etuvetidigene autotemcel,
with the aim to deplete
B cells pre-treatment.

Infusion rate is in accordance
with the summary of product
characteristics (SmPC)

To reduce the occurrence of
potential adverse reactions,
Rituximab infusion should be
preceded by appropriate
premedication with IV
antihistaminic medicinal product,
paracetamol, and steroids,
following standard procedures.
These should be repeated after 6
hours.
375 mg/m²
BusulfanDay-4 to
Day-2
Patients will receive body
weight-based doses of IV
busulfan.

Patients are scheduled to receive
a total of 8 doses, given every
6 hours from Day-4 to Day-2. If
the target AUC of
48 000 ng/mL*h (± 10%) is not
achieved with 8 doses, additional
doses may be administered.
Dosing will be stopped if the
target AUC was reached prior to
the eighth dose.

Dose adjustment will be
performed according to busulfan
PK levels to achieve the target
cumulative AUC of
48 000 ng/mL*h (± 10%).

The etuvetidigene autotemcel
cell infusion will
be scheduled to allow a washout
time of at least 24 hours from the
last dose of busulfan.
The starting dose of busulfan is
based on patient's weight
according to the following
scheme:

• 1 mg/kg/dose (<9 kg);
• 1.2 mg/kg/dose (9 - 16 kg);
• 1.1 mg/kg/dose (>16 - 23 kg);
• 0.95 mg/kg/dose (>23 - 34 kg);
• 0.8 mg/kg/dose (>34 kg).

The subsequent doses of
busulfan should be estimated
from pharmacokinetics (PK)
sampling and adjusted
accordingly. The busulfan PK
analysis should be performed by
serial blood sampling before and
after the infusion of at least two
separate doses usually the first
and fifth dose.

Special attention should be kept
on the busulfan dosing in order
to achieve the target cumulative
AUC of 48 000 ng/ml*h (± 10%).
A dose adjustment should be
performed if the total predicted
AUC shows more than 10%
deviation from the target
(total predicted
AUC is <43 200 ng/mL*h or
>52 800 ng/mL*h).

The number of doses of Busulfan
may be decreased if the
cumulative predicted AUC is too
high.
FludarabineDay-4 and
Day-3
Fludarabine is administered IV
once daily in Day-4 and Day-3.

The infusion rate should be in
accordance with the fludarabine
Summary of Product
Characteristics (SmPC).
30 mg/m²/day

AUC = area under the curve; IV=intravenous; PK=pharmacokinetic; m² = square meter

Prevention and management of infections during pre-treatment

Prophylactic and empiric use of anti-infectives (bacterial, fungal, viral) should be considered for the prevention and management of infections especially during the neutropenic period following conditioning. Infection control measures and isolation procedures should be employed during the hospitalisation according to local standards.

Premedication

Antiallergic medicinal products, such as intravenous chlorpheniramine, are recommended be administered 15-30 minutes before the infusion of etuvetidigene autotemcel to reduce the possibility of an allergic reaction to the infusion.

Active ingredient

Etuvetidigene autotemcel

Etuvetidigene autotemcel is an ex vivo genetically modified autologous CD34+ haematopoietic stem and progenitor cell gene therapy. The genetically modified cells are capable of expressing the functional WAS protein. Following administration, the genetically modified cells engraft and repopulate the haematopoietic compartment. These genetically modified cells containing the corrected WAS protein (WASP) differentiate and produce biologically active lymphoid and myeloid progenitors whose progeny express WAS protein.

Read more about Etuvetidigene autotemcel

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