Active Substance: romiplostim
Common Name: romiplostim
ATC Code: B02BX04
Marketing Authorisation Holder: Amgen Europe B.V.
Active Substance: romiplostim
Authorisation Date: 2009-02-04
Therapeutic Area: Purpura, Thrombocytopenic, Idiopathic
Pharmacotherapeutic Group: Antihaemorrhagics
Nplate is indicated for adult chronic-immune (idiopathic)-thrombocytopenic-purpura (ITP) patients who are refractory to other treatments (e.g. corticosteroids, immunoglobulins).
What is Nplate?
Nplate is a powder that is made up into a solution for injection. Nplate is available with or without a solvent. It contains the active substance romiplostim.
What is Nplate used for?
Nplate is used in adults with long-term immune thrombocytopenic purpura (ITP), a disease in which the patient’s immune system destroys the platelets (components in the blood that help it to clot). Patients with ITP have low platelet counts and are at risk of bleeding.
Nplate is used in patients in whom treatment with medicines such as corticosteroids or immunoglobulins has not worked. Nplate is used both in patients whose spleen has been removed to try to control the disease, and in those who still have a spleen. The spleen is a small organ found behind the stomach, which is involved in the removal of platelets from the blood.
Because the number of patients with ITP is low, the disease is considered ‘rare’, and Nplate was designated an ‘orphan medicine’ (a medicine used in rare diseases) on 27 May 2005.
The medicine can only be obtained with a prescription.
How is Nplate used?
Treatment with Nplate should be supervised by a doctor who has experience in treating blood diseases.
Nplate is given once a week as an injection under the skin. The starting dose depends on the patient’s weight, and is then adjusted every week to maintain platelet counts at target levels. Treatment can be interrupted if platelet counts become too high. Treatment with Nplate should be stopped after four weeks of treatment with the maximum dose of Nplate if the platelet count does not reach levels that are high enough to reduce the risk of bleeding. Once platelet counts have stabilised they should be monitored monthly and the dose adjusted if needed. Doctors should also periodically assess patients who still have a spleen to see if they require surgery. Some patients whose platelet levels have stabilised may be able to inject the medicine themselves after they have been properly trained.
How does Nplate work?
The active substance in Nplate, romiplostim, is a medicine that stimulates the production of platelets. In the body, a hormone called ‘thrombopoietin’ stimulates the production of platelets in the bone marrow. Romiplostim is a protein that has been ‘engineered’ (specifically designed) so that it can attach to and stimulate the same receptors as thrombopoietin. By mimicking the action of thrombopoietin, romiplostim stimulates the production of platelets, increasing blood platelet counts.
How has Nplate been studied?
Nplate has been compared with placebo (a dummy treatment) in two main studies involving adults with long-term ITP. The first study involved 63 patients whose spleens had been removed but whose disease was still not controlled. The second study involved 62 patients who still had their spleens and who had been treated for ITP in the past.
In both studies, the main measure of effectiveness was the number of patients who had a lasting response to treatment. This was classified as the patient’s platelet counts being above 50 million per millilitre for at least six of the last eight weeks of the 24-week treatment period, without the need for any other medicines for ITP. Platelet counts below 30 million per millilitre are considered to put ITP patients at risk of bleeding, while normal counts are between 150 and 400 million per millilitre.
Result of these and 7 further studies involving 1,024 patients treated for up to 5 years or more (376 whose spleen had been removed and 648 who still had a spleen) were later analysed to show the long-term effectiveness of Nplate in controlling platelet counts.
What benefit has Nplate shown during the studies?
Nplate was more effective than placebo at increasing blood platelet counts. In the study of patients whose spleen had been removed, 38% of the patients had a lasting response to treatment with Nplate (16 out of 42), compared with none of the 21 patients receiving placebo. In the study of patients with a spleen, 61% of the patients had a lasting response to treatment with Nplate (25 out of 41), compared with 5% of the patients receiving placebo (1 out of 21).
The later analysis of studies confirmed that Nplate was effective for long-term treatment both in patients whose spleen has been removed and those who still have their spleen.
What is the risk associated with Nplate?
The most common side effects with Nplate (seen in more than 1 patient in 10) include headache and hypersensitivity (allergic reactions). For the full list of all side effects reported with Nplate, see the package leaflet.
Nplate must not be used in people who are hypersensitive (allergic) to romiplostim, any of the other ingredients, or proteins produced by Escherichia coli (a bacterium).
Why has Nplate been approved?
The CHMP noted that the effectiveness of Nplate had been shown in patients who had had their spleen removed, as well as in patients who had not had their spleen removed. The improvement in platelet count was long-lasting and could be considered clinically relevant in both groups, although the treatment only manages symptoms and is not a cure. Therefore, in non-splenectomised patients the need to undergo surgery should be revaluated periodically. The CHMP decided that Nplate’s benefits are greater than its risks and recommended that it be given marketing authorisation.
What measures are being taken to ensure the safe and effective use of Nplate?
A risk management plan has been developed to ensure that Nplate is used as safely as possible. Based on this plan, safety information has been included in the summary of product characteristics and the package leaflet for Nplate, including the appropriate precautions to be followed by healthcare professionals and patients.
The company that markets Nplate will provide doctors in each Member State a ‘dosing calculator’ to help them calculate the sometimes very small volumes of Nplate that need to be injected. Doctors can also be provided with a home administration training pack, which includes materials for doctors on how to train patients who will inject themselves with Nplate at home, and materials for patients on how to prepare the medicine for injection.
Other information about Nplate
The European Commission granted a marketing authorisation valid throughout the European Union for Nplate on 4 February 2009.
For more information about treatment with Nplate, read the package leaflet (also part of the EPAR) or contact your doctor or pharmacist.
Source: European Medicines Agency