romiplostim: clinical use

Prescribing considerations

• Treatment should remain under an experienced haematology specialist.
• Confirm primary ITP and exclude other causes of thrombocytopenia, particularly myelodysplastic syndrome.
• Assess thromboembolic risk, including liver disease, immobility, malignancy, surgery, obesity, smoking and oestrogen exposure.
• Use caution in renal impairment. Moderate-to-severe hepatic impairment requires an explicit benefit-risk assessment because of portal-vein thrombosis risk.
• Investigate loss of response for causes including increased marrow reticulin or neutralising antibodies.
• Record the product name and batch number for biological traceability.

Contraindications and cautions

• Hypersensitivity to romiplostim, any product excipient or proteins derived from E. coli.

Monitoring

• Measure platelet counts frequently while response is being established and periodically once stable.
• Check full blood count and peripheral blood morphology before and during treatment.
• Consider bone-marrow assessment if abnormal morphology, unexplained loss of response or other features raise concern.
• Monitor for thrombosis and clinically important bleeding regardless of the platelet count.
• Monitor platelet counts closely after discontinuation because thrombocytopenia commonly recurs.
• Consider concurrent red-cell and white-cell parameters, particularly after splenectomy.

Clinical pharmacology

Romiplostim is an Fc-peptide fusion protein that activates the c-Mpl thrombopoietin receptor and its intracellular signalling pathways, promoting megakaryocyte activity and platelet production. It has no amino-acid sequence homology with endogenous thrombopoietin.

Formulation and product differences

• The selected powder-only vial presentation is licensed for adults and children aged one year and over; paediatric self-administration is not permitted.
• The selected adult-only reconstitution pack includes water for injections, a vial adapter, syringes, a safety needle and alcohol swabs.
• Both presentations are preservative-free, single-use products requiring reconstitution and protection from light.

Injection

Route: Parenteral

Strengths: 125 micrograms, 250 micrograms