Romiplostim

What it is and how it works

Mechanism of Action Nplate increases platelet production through binding and activation of the TPO receptor, a mechanism analogous to endogenous TPO.

Mechanism class: Thrombopoietin Receptor Agonists

Indications

Nplate is a thrombopoietin receptor agonist indicated for the treatment of thrombocytopenia in: Adult patients with immune thrombocytopenia (ITP) who have had an insufficient response to corticosteroids, immunoglobulins, or splenectomy. Pediatric patients 1 year of age and older with ITP for at least 6 months who have had an insufficient response to corticosteroids, immunoglobulins, or splenectomy. Nplate is indicated to increase survival in adults and in pediatric patients (including term neonates) acutely exposed to myelosuppressive doses of radiation (Hematopoietic Syndrome of Acute Radiation Syndrome [HS-ARS]). Limitations of Use: Nplate is not indicated for the treatment of thrombocytopenia due to myelodysplastic syndrome (MDS) or any cause of thrombocytopenia other than ITP. Nplate should be used only in patients with ITP whose degree of thrombocytopenia and clinical condition increases the risk for bleeding. Nplate should not be used in an attempt to normalize platelet counts.

Dosage and administration (summary)

Patients with Immune Thrombocytopenia (ITP) Recommended Initial Dose: 1 mcg/kg once weekly as a subcutaneous injection. Adjust dose based on platelet response. Patients acutely exposed to myelosuppressive doses of radiation Recommended Dose: 10 mcg/kg administered once as a subcutaneous injection. Administer the dose as soon as possible after suspected or confirmed exposure to myelosuppressive doses of radiation. See Full Prescribing Information for instructions on reconstitution, preparation, and administration.

Contraindications

None. None

Warnings and precautions

In some patients with MDS, Nplate increases blast cell counts and increases the risk of progression to acute myelogenous leukemia. Thrombotic/thromboembolic complications have resulted from increases in platelet counts with Nplate use. Portal vein thrombosis has been reported in patients with chronic liver disease receiving Nplate. Severe thrombocytopenia may persist during Nplate treatment due to neutralizing antibodies or other causes.

Pregnancy

Pregnancy Risk Summary Based on findings from animal reproduction studies, Nplate may cause fetal harm when administered to a pregnant woman. Available data with Nplate use in pregnant women are insufficient to draw conclusions about any drug-associated risk for major birth defects, miscarriage, or adverse maternal or fetal outcomes.

Storage and supply

Nplate (romiplostim) for injection is supplied as a sterile, preservative-free, solid white lyophilized powder in single-dose vials of 125 mcg (NDC-55513-223-01, NDC-55513-223-21), 250 mcg (NDC 55513-221-01, NDC 55513-221-21) and 500 mcg (NDC 55513-222-01, NDC 55513-222-21) of romiplostim.

Source: Romiplostim (Nplate) — US FDA prescribing information, 2026-06-23, DailyMed. Summarised and shortened; the full label governs. Iranian registration, indications and labelling may differ.