Romiplostim
Also known as: AMG 531, AMG531, Megalace, Nplate, romiplostim
Source Romiplostim at Peptiology
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Summary
Romiplostim is a fusion‑protein (peptibody) that activates the thrombopoietin (TPO) receptor to stimulate platelet production. It is approved in many regions for immune thrombocytopenia (ITP) and is being investigated for chemotherapy‑induced thrombocytopenia (CIT) and other marrow‑suppressive conditions. The drug is given by subcutaneous injection and is titrated to raise platelet counts and reduce bleeding or treatment interruptions.
Mechanism of Action
Romiplostim binds to the c‑Mpl (TPO) receptor on megakaryocyte precursors, mimicking endogenous thrombopoietin. This triggers intracellular JAK‑STAT signaling, promoting proliferation, differentiation, and survival of megakaryocytes, which leads to increased platelet formation. Pre‑clinical work and clinical reviews also suggest secondary immunomodulatory effects that may dampen auto‑immune platelet destruction.
What the Research Shows
Randomised phase‑II and phase‑III trials in solid‑tumour patients with persistent CIT have shown that weekly romiplostim rapidly corrects platelet counts (93% vs 12.5% within 3 weeks in a phase‑II study) and enables continuation of chemotherapy (84% vs 36% without dose modifications in a phase‑III trial). Large ITP trials report platelet response rates of 50–90% with good tolerability. Safety data from CIT trials indicate most severe adverse events are attributable to chemotherapy; romiplostim‑related events were mild (nausea, headache) and thromboembolic events occurred in 2% of treated patients. Long‑term concerns such as marrow fibrosis appear rare and reversible after discontinuation.
Reported Benefits
Clinical evidence demonstrates that romiplostim can raise platelet counts to ≥100 ×10⁹/L in the majority of patients with ITP or CIT, reducing bleeding risk and the need for rescue therapies. In chemotherapy settings, it markedly lowers the frequency of dose reductions, delays, or discontinuations, potentially preserving treatment efficacy. The subcutaneous route allows outpatient administration.
Limitations of the Evidence
Romiplostim is not FDA or EMA approved for CIT, so its use in that indication remains off‑label and limited to clinical trial contexts. Evidence for CIT is confined to adult solid‑tumour populations, mainly gastrointestinal cancers, with limited data on other regimens, pediatric patients, or long‑term outcomes. Small risks of venous thromboembolism and reversible marrow fibrosis have been noted, and cost may restrict accessibility.
Safety Considerations
The most common romiplostim‑related adverse events are mild nausea and headache. In CIT trials, grade 3 or higher adverse events were largely chemotherapy‑related; serious romiplostim‑attributed events were rare. Thromboembolic events occurred in about 2% of treated patients. Rare cases of moderate reticulin or collagen fibrosis have been reported but typically resolve after stopping the drug. Regular monitoring of platelet counts and clinical assessment for thrombosis is advised.
How It Is Administered
Romiplostim is supplied as a sterile solution for subcutaneous injection. Dosing is individualized, usually starting at a low weekly dose and titrated upward to maintain platelet counts ≥100 ×10⁹/L. The drug is administered by a healthcare professional or trained patient in an outpatient setting.
Routes of Administration
Goals & Uses
- Chemotherapy-induced thrombocytopenia (investigational)Oncology / Supportive CareLow
- Pediatric ITP managementPediatric HematologyHigh
- Increase platelet count in chronic ITPHematology / ThrombocytopeniaHigh
- Reduce bleeding risk in ITPHematology / HemostasisHigh
- Myelodysplastic syndrome-associated thrombocytopenia (investigational)Hematology / OncologyLow
- Immune thrombocytopenia (ITP)HematologyHigh
Contraindications
- Hematologic malignancies other than ITPOncologicHigh
- Hypersensitivity to romiplostim or any excipientAllergyHigh
- Myelodysplastic syndrome (MDS)OncologicHigh
- PregnancyPopulationModeratePotential fetal risk or insufficient safety data
- Hypersensitivity to romiplostim or product componentsImmunologicHigh
Adverse Effects
- Rebound thrombocytopeniaHematologicalCommon
- HeadacheNeurologicCommonPain in the head or upper neck
- Thromboembolic eventsCardiovascularUncommon
- Bone marrow reticulin formationHematologicalUncommon
- Arthralgia / myalgiaMusculoskeletalCommon
- Progression to AML / MDS exacerbationOncologicRare
- ThromboembolismCardiovascularUncommon
- Bone‑marrow fibrosisHematologicRare
Drug Interactions
- Other thrombopoietin receptor agonistsHigh
- Immunosuppressants (e.g., corticosteroids, azathioprine)Low
- Antiplatelet agents (e.g., aspirin, clopidogrel)Moderate
- Anticoagulants (e.g., warfarin, heparin)Moderate
Population Constraints
- PregnancyReproductive SafetyRelative
- Hepatic impairmentOrgan FunctionRelative
- Patients with active malignancyOncologyRelative
- Renal impairmentOrgan ImpairmentRelative
- LactationReproductiveRelative
- Children <1 yearPediatricAbsolute
- Pediatric patients <1 yearAgeAbsolute
Regulatory Status
- European UnionApprovedApproved: immune thrombocytopenia (ITP)Same as US
- United StatesApprovedApproved: immune thrombocytopenia (ITP)Approved for adults and children ≥1 year
- United KingdomApprovedApproved: immune thrombocytopenia (ITP)
Black‑box warning for potential bone‑marrow fibrosis and increased risk of thromboembolic events; monitor platelet counts and bone‑marrow status.
Evidence & Sources
- Journal ArticleModerateAl-Samkari H2024-01-01T00:00:00.000000Z
- Journal ArticleModerateAl-Samkari H, et al.2026-01-01T00:00:00.000000Z
- Journal ArticleModerateSoff GA, et al.2019-01-01T00:00:00.000000Z
- Journal ArticleModerateGhanima W, et al.2019-01-01T00:00:00.000000Z
- Journal ArticleModerateSemple JW, et al.2024-01-01T00:00:00.000000Z
- Journal ArticleModerateBussel JB, et al.2021-01-01T00:00:00.000000Z
Frequently Asked Questions
What condition is romiplostim officially approved to treat?
Romiplostim is approved in the United States, European Union, Australia, and many other countries for immune thrombocytopenia (ITP) in patients older than one year who have not responded to other therapies.
Can romiplostim be used to prevent chemotherapy‑induced low platelets?
Evidence from phase‑II and phase‑III trials shows romiplostim can raise platelet counts and reduce chemotherapy dose modifications in solid‑tumour patients, but it is not yet approved for this use and remains an off‑label or investigational indication.
How is romiplostim given and how often?
The drug is administered as a subcutaneous injection, typically once weekly. The dose is adjusted based on platelet response, aiming for counts of at least 100 ×10⁹/L.
What are the main safety concerns with romiplostim?
Most side effects are mild, such as nausea or headache. Small risks include venous thromboembolism (about 2% in trials) and reversible marrow fibrosis. Monitoring platelet levels and clinical signs of clotting is recommended.
Does romiplostim replace other ITP treatments?
Romiplostim can reduce the need for corticosteroids, IVIg, or splenectomy in many ITP patients, but treatment decisions are individualized and often involve combination or sequential therapy.
What is Romiplostim?
Romiplostim is a fusion‑protein (peptibody) that activates the thrombopoietin (TPO) receptor to stimulate platelet production. It is approved in many regions for immune thrombocytopenia (ITP) and is being investigated for chemotherapy‑induced thrombocytopenia (CIT) and other marrow‑suppressive conditions. The drug is given by subcutaneous injection and is titrated to raise platelet counts and reduce bleeding or treatment interruptions.
What is Romiplostim used for?
Romiplostim is educationally associated with: Chemotherapy-induced thrombocytopenia (investigational), Pediatric ITP management, Increase platelet count in chronic ITP, Reduce bleeding risk in ITP, Myelodysplastic syndrome-associated thrombocytopenia (investigational), Immune thrombocytopenia (ITP). Educational only — not medical advice.
How is Romiplostim administered?
Recorded routes of administration: Subcutaneous.
What are the potential side effects of Romiplostim?
Reported adverse effects include: Rebound thrombocytopenia, Headache, Thromboembolic events, Bone marrow reticulin formation, Arthralgia / myalgia, Progression to AML / MDS exacerbation, Thromboembolism, Bone‑marrow fibrosis. This list is not exhaustive — consult a qualified clinician.
Who should avoid Romiplostim?
Recorded contraindications: Hematologic malignancies other than ITP, Hypersensitivity to romiplostim or any excipient, Myelodysplastic syndrome (MDS), Pregnancy, Hypersensitivity to romiplostim or product components. Consult a qualified clinician before use.