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.
|Table of Contents|
|What is it used for?|
|How is it used?|
|How does it work?|
|How has it been studied?|
|What benefits has it shown during the studies?|
|What is the risk associated?|
|Why has it been approved?|
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 who have already been treated with medicines such as corticosteroids or immunoglobulins and who have had their spleen removed, if these treatments have not worked. It can also be considered for use in patients who have been treated for ITP who have a spleen and cannot have surgery. The spleen is an organ that is involved in the destruction of platelets. 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.
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.
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.
Romiplostim is produced by a method known as ?recombinant DNA technology?: it is made by a bacterium that has received a gene (DNA), which makes it able to produce romiplostim.
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.
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 most common side effect with Nplate (seen in more than 1 patient in 10) is headache. For the full list of all side effects reported with Nplate, see the Package Leaflet.
Nplate should not be used in people who may be hypersensitive (allergic) to romiplostim, any of the other ingredients, or proteins produced by Escherichia coli (a bacterium).
The Committee for Medicinal Products for Human Use (CHMP) noted that the effectiveness of Nplate had been shown in patients whose spleens had been removed, as well as in patients who still had their spleens. However, because removal of the spleen is a potential cure for ITP, the Committee concluded that Nplate should only be used in patients with a spleen if they are not able to undergo surgery. The CHMP decided that Nplate?s benefits are greater than its risks and recommended that it be given marketing authorisation.