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NPLATE® IN CHILDREN AGED 1 YEAR AND OLDER1

The safety and efficacy of Nplate® in paediatric patients aged 1 year and older were evaluated in two randomised, placebo-controlled studies: a Phase 1/2 and a Phase 3 study.

Similar to data from the adult ITP trials, Nplate® induced high rates of durable and overall platelet response with a similar safety profile in children with symptomatic ITP of more than 6 months duration.

Recommended dosage regimen1

Nplate® is administered weekly as a subcutaneous injection with dose adjustments based on the platelet count response.

Use the lowest dose of Nplate® necessary to achieve and maintain a platelet count ≥50 x 109/L.

The prescribed Nplate® dose may consist of a very small volume (e.g. 0.15 mL). Nplate® should be administered only with a syringe with 0.01 mL graduations.

Initial dose1

The initial dose for Nplate® is 1 μg/kg, based on actual body weight.

Dosage adjustment1

Adjust the weekly dose of Nplate® by increments of 1 μg/kg until the patient achieves a platelet count ≥50 x 109/L, but ≤200 x 109/L. Assess the platelet count weekly until a stable platelet count (≥50 x 109/L for at least 4 weeks without dose adjustment) has been achieved. Obtain platelet counts monthly thereafter. Do not exceed a maximum weekly dose of 10 μg/kg.

PAEDIATRIC DOSE ADJUSTMENT GUIDANCE BASED ON PLATELET COUNT

Count (x 109/L) Action

Initial dose is 1 μg/kg, based on actual body weight

<50

Increase dose by 1 μg/kg.

50 to 200

Dose remains constant.

>200 to <400
for 2 consecutive weeks

Reduce the dose by 1 μg/kg.

≥400

Do not dose. Reinitiate therapy when platelet count is <200 x 109/L.

  • Consider reducing dose by 1 μg/kg on the next scheduled dosing day.
  • Consider maintaining the dose of Nplate® if the platelet count increase was due to the initiation or increase in dose of a concurrently administered ITP medication.

If treatment is interrupted and platelet counts fall, reinitiate therapy at the previous dose of Nplate®.
See Nplate® Product Information for guidance on what to do if the patient loses response.

Dosing calculation1

The volume administered is calculated based on body weight, dose required and concentration of product.

GUIDELINES FOR CALCULATING INDIVIDUAL PATIENT DOSE AND VOLUME OF NPLATE® TO ADMINISTER

Individual patient dose

Individual Patient Dose (μg) = Weight (kg) x Dose in μg/kg

  • Actual body weight at initiation of treatment should always be used when calculating initial dose.
  • In paediatric patients, future dose adjustments are based on changes in platelet counts and changes in body weight. Reassessment of body weight is recommended every 12 weeks.

If Individual Patient Dose
≥23 μg

Reconstitute lyophilised product as described in Nplate® Product Information. The resulting concentration is 500 μg/mL. Volume to Administer (mL) = Individual patient Dose (μg) / 500 μg/mL (round volume to the nearest 0.01 mL).

If Individual Patient Dose
<23 μg

Dilution is required to ensure accurate dosing. Reconstitute lyophilised product and then dilute the product as described in the Nplate® Product Information. The resulting concentration is 125 μg/mL. Volume to Administer (mL) = Individual Patient Dose (μg) / 125 μg/mL (round volume to the nearest 0.01 mL).

Example

10 kg patient is initiated at 1 μg/kg of Nplate®. Individual patient dose (μg) = 10 kg x 1 μg/kg = 10 μg . Because the dose is <23 μg, dilution is required to ensure accurate dosing. Reconstitute and then dilute the product as described in the Nplate® Product Information. The resulting concentration is 125 μg/mL . Volume to Administer (mL) = 10 μg / 125 μg/mL = 0.08 mL

CALCULATOR

Nplate® dosing calculator

If you would like to request hard copies of the Nplate dosing calculator, please email medinfo.JAPAC@amgen.com

Nplate® Dosing Calculator

1: Input patient weight in kg


2: Select Nplate® dose§

μg/kg


3: Note total dose (µg) and injection volume (mL)

Patient’s Total Dose

--

Patient’s Total Dose (μg) =

patient’s weight (kg) x dose (µg/kg)

Injection Volume

--

Injection Volume (mL) =

patient's total dose
500 µg/mL

4: Determine Nplate® vial(s) required for single use.

Using your patient’s total dose and/or injection volume calculated in STEP 3, refer to the full Product Information to determine the appropriate vial required for single-use dose.

§The recommended starting dose for Nplate® is 1 µg/kg.1


CALCULATOR

Nplate® dosing calculator

If you would like to request hard copies of the Nplate dosing calculator, please email medinfo.JAPAC@amgen.com

Paediatric safety profile1

The safety profile up to 24 weeks in the Nplate® treated patients in the Paediatric ITP Randomised Safety Set and the long-term safety in paediatrics were similar to that previously seen for Nplate®.

  • Most adverse events (AEs) were mild (grade 1) or moderate (grade 2) in severity.
  • More paediatric patients receiving Nplate® (24.5%) had serious AEs compared with placebo (4.2%).

    – The AE data for the placebo subjects reflected a shorter duration of exposure from participation in the randomised placebo-controlled studies 20060195 and 20080279.

  • All patients who enrolled in the longer duration extension studies received only Nplate®.
  • There were no fatal AEs for subjects in either treatment group.
  • There were no discontinuations (of study treatment or from study) due to AEs in the paediatric clinical studies.
  • In paediatric patients aged ≥1 year receiving Nplate® for ITP, AEs with a subject incidence of ≥10 % in the overall Paediatric ITP Randomised Safety Set were:

    – Contusion (41%)

    – Upper respiratory tract infection (31%)

    – Oropharyngeal pain (25%)

    – Pyrexia (24%)

    – Diarrhoea (20%)

    – Rash (15%)

    – Abdominal pain upper (14%).

Reference: 1. Nplate® (romiplostim) Approved Product Information. www.amgen.com.au/Nplate.PI.

June 2022 AU-15229

PBS Information: This product is listed on the PBS as a Section 100 item. Refer to PBS Schedule for full authority information. This product is not listed on the PBS for newly diagnosed or persistent immune thrombocytopenia.

REFER TO FULL PRODUCT INFORMATION BEFORE PRESCRIBING; AVAILABLE FROM AMGEN AUSTRALIA PTY LTD,
PH: 1800 803 638 OR AT WWW.AMGEN.COM.AU/NPLATE.PI

For more information on Nplate®, or to report an adverse event or product complaint involving Nplate®, please contact Amgen Medical Information on 1800 803 638 or

visit www.amgenmedinfo.com.au

This site is intended for Australian Healthcare Professionals only.