RotaTeq Mechanism of Action

vaccine, rotavirus




Agencia Lei Va Hong
Full Prescribing Info
Pharmacology: Pharmacodynamics: Efficacy: In clinical trials, efficacy was demonstrated against gastroenteritis due to rotavirus of serotypes G1P[8], G2P[4], G3P[8], G4P[8], and G9P[8].
The protective efficacy of RotaTeq was evaluated in two ways in the placebo-controlled Rotavirus Efficacy and Safety Trial (REST): 1. In 5,673 vaccinated infants (2,834 in the vaccine group) protective efficacy was measured as a reduction in the incidence of rotavirus (RV) gastroenteritis caused by vaccine G serotypes (G1-G4) that occurred at least 14 days after the third dose of vaccine through the first full rotavirus season after vaccination.
2. In 68,038 vaccinated infants (34,035 in the vaccine group) protective efficacy was measured as a reduction in the rate of hospitalisations and emergency department visits for RV gastroenteritis from 14 days after the third dose.
The results of these analyses are presented in the following tables. (See Tables 1 and 2.)

Click on icon to see table/diagram/image

Click on icon to see table/diagram/image

The reduction in incidence of RV gastroenteritis caused by G1-G4 during the second rotavirus season after vaccination was 88.0 % [95 % CI 49.4, 98.7] for severe disease and 62.6 % [95 % CI 44.3, 75.4] for disease of any severity.
Efficacy against G2P[4], G3P-[8], G4P-[8] and G9P-[8] rotavirus was based on fewer cases than for G1. The efficacy observed against G2P[4] most likely resulted from the G2 component of the vaccine.
In a combined post-hoc analysis of REST and another phase III study, the vaccine efficacy against G1-, G2-, G3- and G4-serotype RVG cases (any severity) was 61.5 % [95 % CI: 14.2; 84.2] among infants who were >26 to ≤32 weeks of age at dose 3.
There was an extension of REST conducted in Finland only. This Finnish Extension Study (FES) included a subset of 20,736 subjects that had been enrolled previously in REST. The infants were followed for up to 3 years post-vaccination in the FES.
In REST there were 403 healthcare encounters (20 in the vaccine group and 383 in the placebo group) associated with G1-G4 and G9 RV gastroenteritis in the per protocol population. The additional data from the FES increased the number by 136 encounters in total, including 9 in the vaccine group and 127 in the placebo group. Overall, 31% and 25% of the encounters in the respective groups occurred during the FES.
Based upon combined data from REST and the FES, the reduction up to 3 years post-vaccination in the rate of hospitalisations and emergency department visits for RV gastroenteritis was 94.4% (95% CI: 91.6, 96.2) for serotypes G1-G4, 95.5% (95% CI: 92.8, 97.2) for serotype G1, 81.9% (95% CI: 16.1, 98.0) for serotype G2, 89.0% (95% CI: 53.3, 98.7) for serotype G3, 83.4% (95% CI: 51.2, 95.8) for serotype G4, and 94.2% (95% CI: 62.2, 99.9) for serotype G9. During year 3, there were no health care contacts for RV gastroenteritis in the vaccine group (n=3,112) and one (non-typeable) in the placebo group (n=3,126).
A complete 3-dose vaccination series of RotaTeq should be administered (see Dosage & Administration) to provide the level and duration of protection against rotavirus gastroenteritis that was observed in the clinical studies. However, post hoc analyses indicated that RotaTeq achieved some reduction in the numbers of cases of rotavirus gastroenteritis of sufficient severity to require hospitalisation or an emergency department visit before completion of all three doses (i.e. from approximately 14 days after administration of the first dose onwards).
Efficacy in premature infants: In REST, RotaTeq was administered to approximately 1,000 infants who were born at a gestational age of 25 to 36 weeks. The efficacy of RotaTeq was comparable between this subset of infants and infants born at term.
Effectiveness study data: Post marketing studies demonstrating effectiveness to prevent RV gastroenteritis (RVGE). (See Table 3.)

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Immunogenicity: The immunological mechanism by which RotaTeq protects against rotavirus gastroenteritis is not completely understood. No immunological correlate of protection has currently been identified for rotavirus vaccines. In phase III studies between 92.5 % and 100 % of recipients of RotaTeq achieved a significant rise in serum anti-rotavirus IgA after a three-dose regimen. The vaccine induces an immune response (i.e., appearance of serum neutralising antibody) to the five human-rotavirus proteins expressed on the reassortants (G1, G2, G3, G4 and P [8]).
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