Pharmacological properties : תכונות פרמקולוגיות

Pharmacodynamic Properties

5.1   Pharmacodynamic properties
Pharmacotherapeutic group: Combined bacterial and viral vaccines (diphtheria-Haemophilus influenzae b-pertussis-poliomyelitis-tetanus),

ATC code: J07C A06

When administered alone PRP induces a serological response but it is weak in infants. The covalent binding of PRP to tetanus protein makes it a T-cell dependent antigen which induces a specific IgG anti-PRP response in infants and which can activate an immunological memory.

Immune response after primary vaccination:
Immunogenicity studies in infants given three doses of Pentaxim starting at 2 months of age have shown that, one month after the third dose, all developed a seroprotective antibody level (≥ 0.01 IU/mL) to both diphtheria and tetanus antigens and more than 88% of infants achieved a four-fold rise in PT and FHA antibodies. At least 99% of children had seroprotective antibody titres to poliomyelitis virus types 1, 2 and 3. At least 92% of children achieved anti PRP titres above 0.15 µg/ml.

In the Senegal efficacy trial following a 3 dose primary regimen and after 18 months without booster, the protective efficacy of this acellular pertussis vaccine was found to be lower than the Pasteur Mérieux whole cell pertussis control vaccine. However, lower reactogenicity was demonstrated for this acellular pertussis vaccine in 2 controlled clinical studies when compared to this same whole cell pertussis vaccine.

An immunogenicity study in Sweden given 3 doses of Pentaxim starting at 3 months of age has shown results of the same order of magnitude in terms of seroprotection and seroconversion.

In these clinical studies anti-PRP antibody titres after completion of the primary series with Pentaxim are lower than those obtained when a diphtheria-tetanus-acellular pertussis- poliomyelitis vaccine (TETRAVAC) is administered simultaneously with conjugate Haemophilus influenzae type b vaccine at two separate injection sites. However, the clinical impact of this interaction is not significant after the third dose, whatever the vaccination schedule used.

Immune response after booster injection:
Immunogenicity studies in toddlers who had received a 3-dose primary vaccination series with Pentaxim and a booster dose at 15-18 months of age have shown high antibody responses to all components including over 99% of children with anti-PRP titres above 1.0µg/mL.

Pharmacokinetic Properties

5.2   Pharmacokinetic properties
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