Hui’erning Romiplostim for Injection

1. Indications and Usage
Chronic Immune Thrombocytopenia (ITP):
Treatment of adult patients (≥18 years) who have had an inadequate response to corticosteroids, immunoglobulins, or splenectomy.
Therapeutic Goal:
Used specifically to lower the risk of bleeding in patients with ITP and low platelet counts. It should not be used with the intent of restoring platelet counts to normal physiological levels.
2. Dosage and Administration
Route of Administration:
Subcutaneous (SC) Injection ONLY.
Recommended Dosage:
Initial Dose: 1 µg/kg based on actual body weight, administered once weekly.
Titration: Adjust weekly by 1 µg/kg increments or decrements based on platelet response.
Maximum Dose: 10 µg/kg once weekly.
Critical Administration Instructions:
Preparation: Reconstitute using ONLY preservative-free Sterile Water for Injection. Gently mix; do not shake.
Administration Volume: A syringe with 0.01 mL graduations must be used for accuracy due to potentially small injection volumes.
Single Use: The vial is for single use only. Do not mix contents from multiple vials. Do not store the reconstituted solution for more than 24 hours.
3. Mechanism of Action
TPO Receptor Agonism:
Romiplostim is a peptibody that mimics endogenous thrombopoietin (TPO).
Megakaryocyte Stimulation:
It binds to and activates TPO receptors (c-Mpl) on hematopoietic megakaryocytes, stimulating the proliferation and differentiation of megakaryocytes to increase platelet production in the bone marrow.
4. Safety and Warnings
Thrombotic/Thromboembolic Complications:
Treatment may increase the risk of thrombosis. Platelet counts should be maintained at the minimum level required to prevent bleeding (typically ≥50 × 10⁹/L), avoiding normalization of counts.
Bone Marrow Reticulin Fibrosis:
Dose-dependent increases in bone marrow reticulin fibers and potential progression to myelofibrosis have been reported.
Post-Discontinuation Platelet Drop:
Platelet counts may fall rapidly after discontinuation. Weekly monitoring of platelet counts is required for at least 2 weeks after stopping therapy.
MDS/AML Progression:
In patients with Myelodysplastic Syndromes (MDS)-associated thrombocytopenia, there is a risk of progression to acute myeloid leukemia (AML).
5. Adverse Reactions and Clinical Research
Most Common Adverse Reactions:
Headache, arthralgia, dizziness, insomnia, myalgia, abdominal pain, extremity pain, shoulder pain, dyspepsia, and paresthesia.
Clinical Research Highlights:
Phase 3 trials demonstrated significantly higher response rates (platelet count ≥50 × 10⁹/L) compared to placebo, with reduced risks of severe or life-threatening bleeding.
6. Drug Interactions
Concomitant ITP Therapies:
May be used concurrently with corticosteroids, azathioprine, IVIG, or anti-D immunoglobulin. If platelet counts reach ≥50 × 10⁹/L, concomitant ITP therapies may be tapered or discontinued.
CYP450 System:
As a recombinant fusion protein, it does not interact with CYP450 enzymes.
7. Pharmaceutical Information
Chemical Composition:
Active Ingredient: Romiplostim (Recombinant Fc-peptide fusion protein).
Appearance: White to off-white lyophilized cake or loose body.
Packaging: Single-use vial (250 µg or 500 µg).
Storage: Store in the original carton at 2°C to 8°C. Do not freeze.