What is Silapo?
Silapo is a solution for injection. It is available in pre-filled syringes containing 1000 to 40, 000 international units (IU) of the active substance epoetin zeta.
Silapo is a "biosimilar" medicine, meaning that it is similar to a biological drug already authorized in the European Union (EU) that contains an analogous active substance (also called "reference medicine"). The reference medicine for Silapo is EPREX / ERYPO, which contains epoetin alfa.
For more information on biosimilar medicines, see the document available here which contains a series of questions and answers on the subject.
What is Silapo used for?
Silapo is used to stimulate the production of red blood cells in the following cases:
• in the treatment of anemia (low number of red blood cells) caused by chronic renal failure (prolonged and progressive decrease in the functional capacity of the kidneys) or by other problems affecting the kidneys;
• in the treatment of anemia and to reduce the need for blood transfusions in adult patients receiving chemotherapy for certain types of cancer;
• to increase the amount of blood that patients with moderate anemia can donate before surgery, in view of a possible autotransfusion during or after the operation.
The medicine can only be obtained with a prescription.
How is Silapo used?
Treatment with Silapo should be started under the supervision of doctors who are experienced in managing patients with the medical conditions for which the medicine is indicated. For patients with kidney problems or about to be operated on, Silapo should be injected intravenously (into a vein), while patients undergoing chemotherapy should be administered subcutaneously (under the skin). Dose, frequency of injections and duration of treatment depend on why Silapo is used and are adjusted according to the patient's response. Before treatment, all patients should be checked for iron levels to rule out any deficiencies; iron supplements should be administered throughout the treatment. For more information, see the package leaflet.
How does Silapo work?
A hormone called erythropoietin, which is produced by the kidneys, stimulates the production of red blood cells in the bone marrow.
Anemia caused by erythropoietin deficiency or an insufficient response of the body to erythropoietin naturally present may occur in patients undergoing chemotherapy or with kidney problems. In such cases erythropoietin is used to replace the missing hormone or to increase the number of red blood cells. Erythropoietin can also be used before surgery to increase the number of red blood cells and support the patient in producing more blood for self-giving.
The active substance in Silapo, epoetin zeta, is a replica of human erythropoietin and works exactly like the natural hormone in stimulating red blood cell production. The active ingredient of Silapo, epoetin zeta, is produced with "recombinant DNA technology": that is, it is obtained from a cell in which a gene (DNA) has been introduced that makes it capable of producing erythropoietin.
How has Silapo been studied?
Silapo has been studied to demonstrate its comparability with the reference medicine, EPREX / ERYPO, in experimental models and in humans.
Silapo, given by intravenous injection, was compared with the reference medicine in two main studies involving 922 patients with anemia associated with chronic renal failure and the need for hemodialysis (blood purification technique). The first study compared the effects of Silapo with those of EPREX / ERYPO in correcting the number of red blood cells on 609 patients over 24 weeks. The second study compared the effects of Silapo with those of EPREX / ERYPO in maintaining the number of red blood cells in 313 patients. All patients in the second study had been on EPREX / ERYPO for at least three months before switching to Silapo or continuing EPREX / ERYPO therapy for 12 weeks, after which both groups switched to the other medicine for another 12 weeks. In both studies the main measure of effectiveness was the levels of hemoglobin (a protein contained in red blood cells that carries oxygen within the body) measured during treatment and the dose of epoetin administered.
The company also presented the results of a study on the effects of Silapo by subcutaneous injection on 261 cancer patients during chemotherapy.
What benefit has Silapo shown during the studies?
Silapo was found to be as effective as EPREX / ERYPO in correcting and maintaining the number of red blood cells. In the correction study, hemoglobin levels were around 11.6 g / dl during the last four weeks of the study, compared to about 8.0 g / dl pre-treatment. In the study of patients already being treated with epoetin, hemoglobin levels were maintained to the same extent both with the administration of Silapo and with the administration of EPREX / ERYPO, or about 11.4 g / dl. In both studies the dose of epoetin administered was similar for both medicines.
The study of patients undergoing chemotherapy showed the efficacy of Silapo also by subcutaneous injection, with an improvement in hemoglobin levels similar to that reported in the literature for other epoetins.
What is the risk associated with Silapo?
As with other epoetin-containing medicines, the most common side effect associated with Silapo is an increase in blood pressure that can sometimes induce symptoms of encephalopathy (brain disorders) such as sudden and stabbing migraine-like headaches and confusion . Silapo can also induce rash (eruption) of the skin and flu symptoms. For the full list of all side effects reported with Silapo, see the Package Leaflet. Silapo should not be used in patients who may be hypersensitive (allergic) to epoetin zeta or any of the other ingredients. It should also not be used in the following patients:
• patients who developed pure erythroid aplasia (reduced or blocked red blood cell production) after treatment with any erythropoietin;
• patients with hypertension (high blood pressure) not controlled;
• patients about to undergo surgery with serious cardiovascular problems (ie those affecting the heart and blood vessels) and with a recent heart attack or stroke;
• patients not treatable with drugs against clot formation.
Silapo is not recommended for subcutaneous injection in the treatment of kidney problems as further studies are needed to rule out that it may cause allergic reactions.
Why has Silapo been approved?
The Committee for Medicinal Products for Human Use (CHMP) concluded that, based on the requirements in the European Union, Silapo demonstrated a comparable profile to that of EPREX / ERYPO regarding quality, safety and efficacy. The CHMP therefore considers that, as in the case of EPREX / ERYPO, the benefits outweigh the identified risks and therefore recommended the granting of a marketing authorization for Silapo.
What measures are being taken to ensure the safe use of Silapo?
The company that makes Silapo will provide healthcare professionals in all Member States with information materials including instructions on the safety of the medicine.
More information on Silapo:
On 18 December 2007, the European Commission issued a marketing authorization valid throughout the European Union to STADA Arzneimittel AG for Silapo.
The full EPAR for Silapo can be found here.
Last update of this summary: 11-2007
