Romiplostim: Oligopeptide Research Reference
Thrombopoietin receptor agonist peptibody for immune thrombocytopenia, stimulating platelet production through TPO receptor activation.
Chemical Identity
| Property | Value |
|---|---|
| Molecular Weight | ~59 kDa |
| Peptide Component | 4 copies of TPO receptor-binding peptide |
| Fc Component | Human IgG1 Fc |
| CAS Number | 267639-76-9 |
| Route | SC injection |
Structure
Romiplostim (Nplate) is a peptibody consisting of two disulfide-linked identical polypeptide chains, each containing a human IgG1 Fc domain fused to a TPO receptor-mimetic peptide. Each Fc domain carries two copies of a 14-amino acid peptide that activates the TPO receptor.
Mechanism of Action
The peptibody peptides bind the TPO receptor (c-Mpl) on megakaryocyte precursors, activating JAK2/STAT5 signaling. This stimulates megakaryocyte proliferation, differentiation, and platelet production. The Fc domain extends half-life through FcRn recycling.
Clinical Applications
- Immune thrombocytopenia: Chronic ITP in adults (Nplate)
- Myelodysplastic syndromes: Thrombocytopenia management
- Chemotherapy-induced thrombocytopenia: Investigational
- Surgical thrombocytopenia: Pre-procedural platelet boost
Pharmacokinetics
- Half-life: 3.5 days (dose-dependent)
- Tmax: 7-50 hours (SC)
- Platelet response: Peak at 12-15 days
- Dosing: Weight-based, titrated to platelet count
- Route: SC weekly
Safety and Side Effects
Headache (29%), fatigue (19%), arthralgia (15%), bone marrow reticulin formation (reversible), and rebound thrombocytopenia upon discontinuation. Bone marrow biopsy recommended with prolonged use.
References
- Kuter, D.J., et al. (2006). Romiplostim for chronic ITP. New England Journal of Medicine, 355, 1672-1681.
- Kuter, D.J., et al. (2008). Long-term romiplostim for ITP. Blood, 112, 457-463.
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