What is Ambirix?
Ambirix is a vaccine available as a suspension for injection, containing the inactivated (that is killed) hepatitis A virus and parts of the hepatitis B virus as active substances.
What is Ambirix used for?
Ambirix is used to protect against hepatitis A and hepatitis B (diseases that affect the liver), in subjects one to 15 years of age who are not already immune to these two diseases.
Ambirix is given according to a two-dose vaccination protocol, so protection against hepatitis B may not be achieved until after the second dose. For this reason, Ambirix should only be used in cases where there is a reduced risk of hepatitis B infection during the vaccination course and when it is certain that the two-dose vaccination course can be completed.
The medicine can only be obtained with a prescription.
How is Ambirix used?
The vaccination scheme of Ambirix is composed of two doses administered 6-12 months apart. The vaccine is given by injection into the upper arm muscle or into the thigh in very young children. People who receive the first dose must complete the cycle with Ambirix.
In the case of a booster dose for hepatitis A or B, Ambirix or a separate hepatitis A or B vaccine can be administered.
How does Ambirix work?
Ambirix is a vaccine. Vaccines act by "teaching" the immune system (the body's natural defenses) to defend itself against a disease. Ambirix contains small amounts of inactivated hepatitis A viruses and "surface antigen" (surface proteins) of the hepatitis B virus. When a child receives the vaccine, the immune system recognizes viruses and surface antigens as "strangers" and produces antibodies against them. If exposed to viruses in the future, the immune system will be able to produce antibodies more quickly. Antibodies help protect against diseases caused by these viruses.
The vaccine is "adsorbed". This means that viruses and surface antigens are fixed on aluminum compounds to stimulate a better response. The surface antigens of the hepatitis B virus are obtained by a method called "recombinant DNA technique": they are produced by a yeast that has received a gene (DNA) which makes it capable of producing proteins.
The active substances of Ambirix are available in other vaccines authorized in the European Union (EU): Ambirix contains the same components as Twinrix Adult, authorized since 1996, and Twinrix Pediatric, authorized since 1997. The three vaccines are used for protection from the same diseases but Twinrix Adult and Twinrix Pediatric are administered following a three-dose protocol.
How has Ambirix been studied?
Since Ambirix and Twinrix Adult contain identical ingredients, some of the data used to support the use of Twinrix Adult have been taken up to justify the use of Ambirix.
Three main studies on Ambirix were conducted on a total of 615 subjects starting from one year of age. All children received two doses of Ambirix six months apart. Two of the studies compared Ambirix with other hepatitis A and B vaccines. The main measure of effectiveness was the percentage of vaccinated children who developed protective antibody levels one month after the last injection.
An additional study of 208 subjects compared the efficacy of the vaccine when the interval between the two injections was from 6 months to 12 months.
What benefit has Ambirix shown during the studies?
Ambirix has led to the development of protective antibody levels against hepatitis A and B in a percentage between 98 and 100% of children vaccinated one month after the last injection. These levels were maintained in over 93% of children after two years. Ambirix has demonstrated the same efficacy as other hepatitis A and B vaccines, once the complete vaccination course has ended. However, complete protection against hepatitis B was found only after the second dose of Ambirix was administered.
The additional study showed similar levels of protection with Ambirix with an interval of 6 and 12 months between injections.
What is the risk associated with Ambirix?
The most common side effects of Ambirix (seen in over 1 in 10 doses of the vaccine) are headache, loss of appetite, pain at the injection site, redness, fatigue (tiredness) and irritability or nervousness. For the full list of all side effects reported with Ambirix, see the Package Leaflet.
Ambirix should not be used in people who may be hypersensitive (allergic) to any of the active ingredients, to any of the other ingredients, or to neomycin (an antibiotic). It must also not be used in people who have had an allergic reaction after receiving hepatitis A or hepatitis B vaccines. The vaccination with Ambirix should be postponed in patients with a sudden high fever. The vaccine should never be injected into a vein.
Why has Ambirix been approved?
The Committee for Medicinal Products for Human Use (CHMP) has determined that Ambirix's benefits are greater than its risks for use in non-immune subjects from 1 year up to and including the age of 15 to protect against hepatitis A and hepatitis B. The committee recommended that Ambirix be given marketing authorization.
More information on Ambirix:
On 30 August 2002, the European Commission issued a marketing authorization for Ambirix, valid throughout the European Union, to GlaxoSmithKline Biologicals sa. The marketing authorization was renewed on 30 August 2007.
The full EPAR for Ambirix can be found here.
Last update of this summary: 02-2008.
