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(roe mi PLOE stim)

Index Terms

  • AMG 531

Dosage Forms

Excipient information presented when available (limited, particularly for generics); consult specific product labeling.

Solution Reconstituted, Subcutaneous [preservative free]:

Nplate: 250 mcg (1 ea); 500 mcg (1 ea)

Brand Names: U.S.

  • Nplate

Pharmacologic Category

  • Colony Stimulating Factor
  • Hematopoietic Agent
  • Thrombopoietic Agent


Thrombopoietin (TPO) peptide mimetic which increases platelet counts in ITP by binding to and activating the human TPO receptor.


SubQ: Slow (Wang, 2004)

Onset of Action

Platelet count increase: SubQ: 4 to 9 days (Wang, 2004); Peak platelet count increase: Days 12 to 16 (Wang, 2004)

Time to Peak

SubQ: Median: 14 hours (range: 7 to 50 hours)

Duration of Action

Platelet counts return to baseline by day 28 (Wang, 2004)

Half-Life Elimination

Median: 3.5 days (range: 1 to 34 days)

Use: Labeled Indications

Chronic immune thrombocytopenia: Treatment of thrombocytopenia in patients with chronic immune thrombocytopenia (ITP) who have had insufficient response to corticosteroids, immune globulin, or splenectomy

Limitations of use: Should be used only when the degree of thrombocytopenia and clinical condition increase the risk for bleeding; should not be used in attempt to normalize platelet counts; not indicated for the treatment of thrombocytopenia due to myelodysplastic syndrome or any cause of thrombocytopenia other than chronic ITP.


There are no contraindications listed in the US labeling.

Canadian labeling: Hypersensitivity to romiplostim or any component of the formulation; known history of sensitivity or allergy to any E. coli-derived product.

Dosing: Adult

Note: Initial dose is based on actual body weight. Use the lowest dose sufficient to maintain platelet count ≥50,000/mm3 as necessary to reduce the risk of bleeding. Adjust dose based on platelet count response; discontinue if platelet count does not respond to a level that avoids clinically important bleeding after 4 weeks at the maximum recommended dose. Do not use to normalize platelet counts.

Chronic immune thrombocytopenia (ITP): SubQ: Initial: 1 mcg/kg once weekly; adjust dose by 1 mcg/kg/week increments to achieve platelet count ≥50,000/mm3 and to reduce the risk of bleeding; Maximum dose: 10 mcg/kg/week (median dose needed to achieve response in clinical trials: 2 mcg/kg)

Dosage adjustment recommendations:

Platelet count <50,000/mm3:

US labeling: Increase weekly dose by 1 mcg/kg

Canadian labeling: Increase weekly dose by 1 mcg/kg every 1 to 2 weeks

Platelet count >200,000/mm3 for 2 consecutive weeks: Reduce weekly dose by 1 mcg/kg

Platelet count >400,000/mm3: Withhold dose; assess platelet count weekly; when platelet count <200,000/mm3, resume with the weekly dose reduced by 1 mcg/kg

Dosing: Geriatric

Refer to adult dosing.

Dosing: Renal Impairment

There are no dosage adjustments provided in the manufacturer’s labeling (has not been studied).

Dosing: Hepatic Impairment

There are no dosage adjustments provided in the manufacturer’s labeling (has not been studied).


Reconstitute with only preservative free SWFI (add 0.72 mL to 250 mcg vial or 1.2 mL to 500 mcg vial). Do not use bacteriostatic water for injection. Gently invert vial and swirl; do not shake. Usually dissolves within 2 minutes.


Administer SubQ. Administration volume may be small; use appropriate syringe (with graduations to 0.01 mL) for administration. Verify calculations, final concentration, and volume drawn up for administration.

Dietary Considerations

Some products may contain sucrose.


Store intact vials refrigerated at 2°C to 8°C (36°F to 46°F); do not freeze. Protect from light. Store in original carton until use. Reconstituted solution may be stored at room temperature of 25°C (77°F) or refrigerated at 2°C to 8°C (36°F to 46°F) for up to 24 hours prior to administration. Protect reconstituted solution from light; discard any unused portion.

Drug Interactions

There are no known significant interactions.

Adverse Reactions


Central nervous system: Headache (35%), dizziness (17%), insomnia (16%)

Gastrointestinal: Abdominal pain (11%)

Hematologic & oncologic: Circulating myeloblasts increased (MDS patients: 17%)

Neuromuscular & skeletal: Arthralgia (26%), myalgia (14%), limb pain (13%)

1% to 10%:

Gastrointestinal: Dyspepsia (7%)

Hematologic & oncologic: Rebound thrombocytopenia (7%), AML (MDS patients: 4% to 6%)

Neuromuscular & skeletal: Shoulder pain (8%), paresthesia (6%)

Miscellaneous: Antibody formation (no correlation between antibody development and drug safety or efficacy has been established: romiplostim 3% to 4%; TPO 1% to 3%)

Frequency not defined:

Hematologic & oncologic: Bone marrow reticulin formation/deposition

<1% (Limited to important or life-threatening): Angioedema, erythromelalgia, hypersensitivity, marrow fibrosis with collagen, thromboembolism, thrombotic complications


Concerns related to adverse effects:

• Bone marrow reticulin: May increase the risk for bone marrow reticulin formation or progression; this formation may improve upon discontinuation of therapy.

• Malignancy: Progression from existing myelodysplastic syndrome (MDS) to acute myeloid leukemia (AML) has been observed in clinical trials studying romiplostim for severe thrombocytopenia associated with MDS (not an approved indication); a higher percentage of patients receiving romiplostim experienced transformation to AML (compared to placebo). An increase in the percentage of circulating myeloblasts in peripheral blood counts was also noted (both in patients who progressed to AML and in those who did not); blast cells decreased to baseline after discontinuation in some patients.

• Thromboembolism: Thromboembolism or thrombotic complications may occur with increased platelets. Follow dosage adjustment recommendations to minimize the risk for thrombotic or thromboembolic complications. Use with caution in patients with a history of cerebrovascular disease.

Disease-related concerns:

• Hepatic impairment: Use with caution in patients with chronic liver disease; portal vein thrombosis has been reported in these patients.

Concurrent drug therapy issues:

• Concomitant ITP medications: May be used in combination with other therapies for ITP, including corticosteroids, danazol, azathioprine, immune globulin, or Rho(D) immune globulin. Reduce dose of or discontinue ITP medications when platelet count ≥50,000/mm3.

Other warnings/precautions:

• Appropriate use: Indicated only when the degree of thrombocytopenia and clinical conditions increase the risk for bleeding; use the lowest dose necessary to achieve and maintain platelet count ≥50,000/mm3. Do not use to normalize platelet counts. Discontinue if platelet count does not respond to a level to avoid clinically important bleeding after 4 weeks at the maximum recommended dose. Not indicated for the treatment of thrombocytopenia due to MDS or any cause of thrombocytopenia other than chronic ITP. Only use in patients with ITP whose degree of thrombocytopenia and clinical condition increases the risk for bleeding.

• Discontinuation: Upon discontinuation of therapy, rebound thrombocytopenia and risk of bleeding may develop. Severity may be greater than pretreatment level. Monitor CBCs and platelet counts weekly for at least 2 weeks after discontinuation.

• Error prevention: Overdose may result in thrombotic/thromboembolic complications due to excessive platelet levels; underdose may result in lack of platelet response and potential for bleeding. Use caution when calculating dose and appropriate volume for administration (volume may be very small; administer with syringe that allows for 0.01 mL graduations).

• Hyporesponsiveness: Lack of response or failure to maintain platelet response should trigger investigation in to causative factors, including neutralizing antibodies to romiplostim.

Monitoring Parameters

CBC with differential and platelets (baseline, during treatment [weekly until platelet response stable for at least 4 weeks then monthly] and weekly for at least 2 weeks following discontinuation or completion of treatment)

Evaluate for neutralizing antibodies in patients with inadequate response (blood samples may be submitted to the manufacturer for assay [1-800-772-6436]).

Pregnancy Risk Factor


Pregnancy Considerations

Adverse events have been observed in animal reproduction studies. Use during pregnancy only if the potential benefit to the mother outweighs the potential risk to the fetus.

Women exposed to romiplostim during pregnancy are encouraged to enroll in the Nplate pregnancy (1-800-772-6436). In Canada, women who become pregnant during treatment are encouraged to enroll in Amgen’s Pregnancy Surveillance Program (1-866-512-6436).

Patient Education

• Discuss specific use of drug and side effects with patient as it relates to treatment. (HCAHPS: During this hospital stay, were you given any medicine that you had not taken before? Before giving you any new medicine, how often did hospital staff tell you what the medicine was for? How often did hospital staff describe possible side effects in a way you could understand?)

• Patient may experience headache, joint pain, nausea, muscle pain, muscle weakness, or insomnia. Have patient report immediately to prescriber signs of severe cerebrovascular disease (change in strength on one side is greater than the other, trouble speaking or thinking, change in balance, or change in eyesight), signs of DVT (edema, warmth, numbness, change in color, or pain in the extremities), severe dizziness, passing out, shortness of breath, burning or numbness feeling, bruising, bleeding, coughing up blood, angina, severe abdominal pain, or vision changes (HCAHPS).

• Educate patient about signs of a significant reaction (eg, wheezing; chest tightness; fever; itching; bad cough; blue skin color; seizures; or swelling of face, lips, tongue, or throat). Note: This is not a comprehensive list of all side effects. Patient should consult prescriber for additional questions.

Intended Use and Disclaimer: Should not be printed and given to patients. This information is intended to serve as a concise initial reference for health care professionals to use when discussing medications with a patient. You must ultimately rely on your own discretion, experience, and judgment in diagnosing, treating, and advising patients.