CLINICAL PHARMACOLOGY
Mechanism Of Action
VAQTA has been shown to elicit
antibodies to hepatitis A as measured by ELISA.
Protection from hepatitis A
disease has been shown to be related to the presence of antibody. However, the
lowest titer needed to confer protection has not been determined.
Clinical Studies
Efficacy Of VAQTA: The Monroe
Clinical Study
The immunogenicity and
protective efficacy of VAQTA were evaluated in a randomized, double-blind,
placebo-controlled study involving 1037 susceptible healthy children and
adolescents 2 through 16 years of age in a U.S. community with recurrent
outbreaks of hepatitis A (The Monroe Efficacy Study). All of these children
were Caucasian, and there were 51.5% male and 48.5% female. Each child received
an intramuscular dose of VAQTA (25U) (N=519) or placebo (alum diluent) (N=518).
Among those individuals who were initially seronegative (measured by a
modification of the HAVAB radioimmunoassay [RIA]), seroconversion
was achieved in > 99% of vaccine recipients within 4 weeks after vaccination.
The onset of seroconversion following a single dose of VAQTA was shown to
parallel the onset of protection against clinical hepatitis A disease.
Because of the long incubation
period of the disease (approximately 20 to 50 days, or longer in children),
clinical efficacy was based on confirmed cases6 of hepatitis A
occurring ≥ 50 days after vaccination in
order to exclude any children incubating the infection before vaccination. In subjects who were initially seronegative, the
protective efficacy of a single dose of VAQTA was observed to be 100% with 21
cases of clinically confirmed hepatitis A occurring in the placebo group and
none in the vaccine group (p < 0.001). The number of clinically confirmed
cases of hepatitis A ≥ 30 days after
vaccination were also compared. In this analysis, 28 cases of clinically
confirmed hepatitis A occurred in the placebo group while none occurred in the
vaccine group ≥ 30 days after vaccination. In addition, it was observed in this trial that no cases of
clinically confirmed hepatitis A occurred in the vaccine group after day 16.7
Following demonstration of protection with a single dose and termination of the
study, a booster dose was administered to a subset of vaccinees 6, 12, or 18
months after the primary dose.
No cases of clinically
confirmed hepatitis A disease ≥ 50 days
after vaccination have occurred in those vaccinees from The Monroe Efficacy
Study monitored for up to 9 years.
Other Clinical Studies
The efficacy of VAQTA in other
age groups was based upon immunogenicity measured 4 to 6 weeks following
vaccination. VAQTA was found to be immunogenic in all age groups.
Children — 12 through 23 Months
of Age
In a clinical trial, children
12 through 23 months of age were randomized to receive the first dose of VAQTA
with or without M-M-R II and VARIVAX (N=617) and the second dose of VAQTA with
or without Tripedia and optionally either oral poliovirus vaccine (no longer
licensed in the US) or IPOL(N=555). The race distribution of study subjects who
received at least one dose of VAQTA was as follows: 56.7% Caucasian; 17.5%
Hispanic-American; 14.3% African-American; 7.0% Native American; 3.4% other;
0.8% Oriental; 0.2% Asian; and 0.2% Indian. The distribution of subjects by
gender was 53.6% male and 46.4% female. In the analysis population, there were
471 initially seronegative children 12 through 23 months of age, who received
the first dose of VAQTA with (N=237) or without (N=234) M-M-R II and VARIVAX of
whom 96% (95% CI: 93.7%, 97.5%) seroconverted (defined as having an anti-HAV
titer ≥ 10 mIU/mL) post dose 1 with an anti-HAV GMT of 48 mIU/mL (95% CI:
44.7, 51.6). There were 343 children in the analysis population who received
the second dose of VAQTA with (N=168) or without (N=175) Tripedia and optional
oral poliovirus vaccine or IPOL of whom 100% (95% CI: 99.3%, 100%)
seroconverted post dose 2 with an anti-HAV GMT of 6920 mIU/mL (95% CI: 6136,
7801). Of children who received only VAQTA at both visits, 100% (n=97)
seroconverted after the second dose of VAQTA.
In a clinical trial involving
653 healthy children 12 to 15 months of age, 330 were randomized to receive
VAQTA, ProQuad, and pneumococcal 7-valent conjugate vaccine concomitantly, and
323 were randomized to receive ProQuad and pneumococcal 7-valent conjugate
vaccine concomitantly followed by VAQTA 6 weeks later. The race distribution of
the study subjects was as follows: 60.3% Caucasian; 21.6% African-American;
9.5% Hispanic-American; 7.2% other; 1.1% Asian/Pacific; and 0.3% Native
American. The distribution of subjects by gender was 50.7% male and 49.3%
female. In the analysis population, the seropositivity rate for hepatitis A
antibody (defined as the percent of subjects with an anti-HAV titer ≥ 10
mIU/mL) was 100% (n=182; 95% CI: 98.0%, 100%) post dose 2 with an anti-HAV GMT
of 4977 mIU/mL (95% CI: 4068, 6089) when VAQTA was given with ProQuad and
pneumococcal 7-valent conjugate vaccine and 99.4% (n=159, 95% CI: 96.5%, 100%)
post dose 2 with an anti-HAV GMT of 6123 mIU/mL (95% CI: 4826, 7770) when VAQTA
alone was given. These seropositivity rates were similar whether VAQTA was
administered with or without ProQuad and pneumococcal 7-valent conjugate
vaccine.
In an open, multicenter,
randomized study involving 617 children 15 months of age, 306 were randomized
to receive VAQTA with or without PedvaxHIB and INFANRIX, and 311 were
randomized to receive VAQTA with or without PedvaxHIB. The race distribution of
the study subjects was as follows: 63.9% Caucasian; 17.5% Hispanic-American;
14.7% Black; 2.6% other; and 1.3% Asian. The distribution of subjects by gender
was 54.0% male and 46.0% female. The seropositivity rate for hepatitis A
antibody (defined as the percent of subjects with an anti-HAV titer ≥ 10
mIU/mL) 4 weeks post dose 2 was 100% (n=208, 95% CI: 98.2%, 100.0%) in those
who received VAQTA concomitantly with PedvaxHIB and INFANRIX or concomitantly
with PedvaxHIB. In those subjects who received VAQTA alone, the seropositivity
rate for hepatitis A antibody was 100% (n=183, 95% CI: 98.0%, 100.0%),
regardless of baseline hepatitis A serostatus. Overall, the anti-HAV GMT in the
concomitant groups was 3616.5 mIU/mL (95% CI: 3084.5, 4240.2). The anti-HAV GMT
in the nonconcomitant groups was 4712.6 mIU/mL (95% CI: 3996.8, 5556.8).
Comparable responses were observed in both the initially seronegative and
seropositive subjects.
In three combined clinical
studies 1022 initially seronegative subjects received 2 doses of VAQTA alone or
concomitantly with other vaccines. Of the seronegative subjects, 99.9% achieved
an anti-HAV titer ≥ 10 mIU/mL (95% CI: 99.5%, 100%) and an anti-HAV GMT of
5392.1 mIU/mL (95% CI: 4996.5, 5819.0) 4 weeks following dose 2 of VAQTA.
Children/Adolescents — 2 Years
through 18 Years of Age
Immunogenicity data were
combined from eleven randomized clinical studies in children and adolescents 2
through 18 years of age who received VAQTA (25U/0.5 mL). These included
administration of VAQTA in varying doses and regimens (N=404 received 25U/0.5
mL), the Monroe Efficacy Study (N=973), and comparison studies for process and
formulation changes (N=1238). The race distribution of the study subjects who
received at least one dose of VAQTA in these studies was as follows: 84.8%
Caucasian; 10.6% American Indian; 2.3% African-American; 1.5%
Hispanic-American; 0.6% other; 0.2% Oriental. The distribution of subjects by
gender was 51.2% male and 48.8% female. The proportions of subjects who
seroconverted 4 weeks after the first and second doses administered 6 months
apart were 97% (n=1230; 95% CI: 96%, 98%) and 100% (n=1057; 95% CI: 99.5%,
100%) of subjects with anti-HAV GMTs of 43 mIU/mL (95% CI: 40, 45) and 10,077
mIU/mL (95% CI: 9394, 10,810), respectively.
Adults — 19 Years of Age and
Older
Immunogenicity data were
combined from five randomized clinical studies in adults 19 years of age and
older who received VAQTA (50U/1-mL). One single-blind study evaluated doses of
VAQTA with varying amounts of viral antigen and/or alum content in healthy
adults ≥ 170 pounds and ≥ 30 years of age (N=208 adults administered
50U/1-mL dose). One open-label study evaluated VAQTA given with immune globulin
or alone (N=164 adults who received VAQTA alone). A third study was
single-blind and evaluated 3 different lots of VAQTA (N=1112). The fourth study
was single-blind and evaluated doses of VAQTA with varying amounts of viral
antigen in healthy adults ≥ 170 pounds and ≥ 30 years of age (N=159
adults administered the 50U/1-mL dose). The fifth study was an open-label study
to evaluate various regimens for time of administration of the booster dose of
VAQTA (6, 12, and 18 months post dose 1, N=354). The race distribution of the
study subjects who received at least one dose of VAQTA in these studies was as
follows: 93.2% Caucasian; 2.5% African-American; 2.1% Hispanic-American; 1.4%
Oriental; 0.5% other; 0.3% American Indian. The distribution of subjects by
gender was 44.8% male and 55.2% female. The proportion of subjects who
seroconverted 4 weeks after the first and second doses administered 6 months
apart was 95% (n=1411; 95% CI: 94%, 96%) and 99.9% (n=1244; 95% CI: 99.4%,
100%) with GMTs of 37 mIU/mL (95% CI: 35, 38) and 6013 mIU/mL (95% CI: 5592,
6467), respectively. Furthermore, at 2 weeks postvaccination, 69.2% (n=744; 95%
CI: 65.7%, 72.5%) of adults seroconverted with an anti-HAV GMT of 16 mIU/mL
after a single dose of VAQTA.
Timing Of Booster Dose
Administration
Children/Adolescents — 2
through 18 Years of Age
In the Monroe Efficacy Study,
children were administered a second dose of VAQTA (25U/0.5 mL) 6, 12, or 18
months following the initial dose. For subjects who received both doses of VAQTA,
the GMTs and proportions of subjects who seroconverted 4 weeks after the
booster dose administered 6, 12, and 18 months after the first dose are
presented in Table 9.
Table 9 : Children/Adolescents from the Monroe
Efficacy Study Seroconversion Rates (%) and Geometric Mean Titers (GMT) for
Cohorts of Initially Seronegative Vaccinees at the Time of the Booster (25U)
and 4 Weeks Later
Months Following Initial 25U Dose |
Cohort*
(n=960) 0 and 6 Months |
Cohort*
(n=35) 0 and 12 Months |
Cohort*
(n=39) 0 and 18 Months |
Seroconversion Rate GMT (mIU/mL) (95% CI) |
6 |
97% 107 (98, 117) |
__ |
__ |
7 |
100% 10433 (9681, 11243) |
__ |
__ |
12 |
__ |
91% 48 (33, 71) |
__ |
13 |
__ |
100% 12308 (9337, 16226) |
__ |
18 |
__ |
__ |
90% 50 (28, 89) |
19 |
__ |
__ |
100% 9591 (7613, 12082) |
* Blood samples were taken at prebooster and postbooster
time points. |
Adults — 19 years of age and older
Among the 5 randomized clinical studies in adults 19
years of age and older described in Section 14.2, there were additional data in
which a booster dose of VAQTA (50U/1-mL) was administered 12 or 18 months after
the first dose. For subjects in these studies who received both doses of VAQTA,
the proportions who seroconverted 4 weeks after the booster dose administered
6, 12, and 18 months after the first dose were 100% of 1201 subjects, 98% of 91
subjects, and 100% of 84 subjects, respectively. GMTs in mIU/mL one month after
the subjects received the booster dose at 6, 12, or 18 months after the primary
dose were 5987 mIU/mL (95% CI: 5561, 6445), 4896 mIU/mL (95% CI: 3589, 6679),
and 6043 mIU/mL (95% CI: 4687, 7793), respectively.
Duration Of Immune Response
In follow-up of subjects in The Monroe Efficacy Study, in
children ( ≥ 2 years of age) and adolescents who received two doses (25U)
of VAQTA, detectable levels of anti-HAV antibodies ( ≥ 10 mIU/mL) were
present in 100% of subjects for at least 10 years postvaccination. In subjects
who received VAQTA at 0 and 6 months, the GMT was 819 mIU/mL (n=175) at 2.5 to
3.5 years and 505 mIU/mL (n=174) at 5 to 6 years, and 574 mIU/mL (n=114) at 10
years postvaccination. In subjects who received VAQTA at 0 and 12 months, the
GMT was 2224 mIU/mL (n=49) at 2.5 to 3.5 years, 1191 mIU/mL (n=47) at 5 to 6
years, and 1005 mIU/mL (n=36) at 10 years postvaccination. In subjects who
received VAQTA at 0 and 18 months, the GMT was 2501 mIU/mL (n=53) at 2.5 to 3.5
years, 1614 mIU/mL (n=56) at 5 to 6 years, and 1507 mIU/mL (n=41) at 10 years
postvaccination.
In adults that were administered VAQTA at 0 and 6 months,
the hepatitis A antibody response to date has been shown to persist at least 6
years. Detectable levels of anti-HAV antibodies ( ≥ 10 mIU/mL) were
present in 100% (378/378) of subjects with a GMT of 1734 mIU/mL at 1 year,
99.2% (252/254) of subjects with a GMT of 687 mIU/mL at 2 to 3 years, 99.1%
(219/221) of subjects with a GMT of 605 mIU/mL at 4 years, and 99.4% (170/171)
of subjects with a GMT of 684 mIU/mL at 6 years postvaccination.
The total duration of the protective effect of VAQTA in
healthy vaccinees is unknown at present.
Concomitant Administration Of VAQTA and Immune Globulin
The concurrent use of VAQTA (50U) and immune globulin
(IG, 0.06 mL/kg) was evaluated in an open-label, randomized clinical study
involving 294 healthy adults 18 to 39 years of age. Adults were randomized to
receive 2 doses of VAQTA 24 weeks apart (N=129), the first dose of VAQTA
concomitant with a dose of IG followed by the second dose of VAQTA alone 24
weeks later (N=135), or IG alone (N=30). The race distribution of the study
subjects who received at least one dose of VAQTA or IG in this study was as
follows: 92.3% Caucasian; 4.0% Hispanic-American; 3.0% African-American; 0.3%
Native American; 0.3% Asian/Pacific. The distribution of subjects by gender was
28.7% male and 71.3% female. Table 10 provides seroconversion rates and
geometric mean titers (GMTs) at 4 and 24 weeks after the first dose in each treatment
group and at one month after a booster dose of VAQTA (administered at 24 weeks)
[see DRUG INTERACTIONS].
Table 10 : Seroconversion Rates (%) and Geometric Mean
Titers (GMT) After Vaccination with VAQTA Plus IG, VAQTA Alone, and IG Alone
Weeks |
VAQTA plus IG |
VAQTA |
IG |
Seroconversion Rate GMT (mIU/mL) (95% CI) |
4 |
100% |
96% |
87% |
42 (39, 45) |
38 (33, 42) |
19 (15, 23) |
(n=129) |
(n=135) |
(n=30) |
24 |
92% |
97%* |
0% |
83 (65, 105) |
137* (112, 169) |
Undetectable† |
(n=125) |
(n=132) |
(n=28) |
28 |
100% |
100% |
N/A |
4872 (3716, 6388) (n=114) |
6498 (5111, 8261) (n=128) |
|
*The seroconversion rate and the GMT in the group
receiving VAQTA alone were significantly higher than in the group receiving
VAQTA plus IG (p=0.05, p < 0.001, respectively).
†Undetectable is defined as < 10mIU/mL.
N/A = Not Applicable. |
Interchangeability Of The Booster Dose
A randomized, double-blind clinical study in 537 healthy
adults, 18 to 83 years of age, evaluated the immune response to a booster dose
of VAQTA and HAVRIX given at 6 or 12 months following an initial dose of
HAVRIX. Subjects were randomized to receive VAQTA (50U) as a booster dose 6
months (N=232) or 12 months (N=124) following an initial dose of HAVRIX or
HAVRIX (1440 EL. U) as a booster dose 6 months (N=118) or 12 months (N=63)
following an initial dose of HAVRIX. The race distribution of the study
subjects who received the booster dose of VAQTA or HAVRIX in this study was as
follows: 87.2% Caucasian; 8.0% African-American; 1.9% Hispanic-American; 1.3%
Oriental; 0.9% Asian; 0.4% Indian; 0.4% other. The distribution of subjects by
gender was 44.9% male and 55.1% female. When VAQTA was given as a booster dose
following HAVRIX, the vaccine produced an adequate immune response (see Table
11) [see DOSAGE AND ADMINISTRATION].
Table 11 : Seropositivity Rate, Booster Response Rate*
and Geometric Mean Titer 4 Weeks Following a Booster Dose of VAQTA or HAVRIX
Administered 6 to 12 Months After First Dose of HAVRIX†
First Dose |
Booster Dose |
Seropositivity Rate |
Booster Response Rate* |
Geometric Mean Titer |
HAVRIX |
VAQTA |
99.7% (n=313) |
86.1% (n=310) |
3272 (n=313) |
1440 EL.U. |
50 U |
HAVRIX |
HAVRIX |
99.3% (n=151) |
80.1% (n=151) |
2423 (n=151) |
1440 EL.U. |
1440 EL.U. |
*Booster Response Rate is defined as greater than or
equal to a tenfold rise from prebooster to postbooster titer and postbooster
titer ≥ 100 mIU/mL.
†Study conducted in adults 18 years of age and older. |
Immune Response To Concomitantly Administered Vaccines
Clinical Studies of VAQTA with M-M-R II, VARIVAX, and
Tripedia
In the clinical trial in which children 12 months of age
received the first dose of VAQTA concomitantly with M-M-R II and VARIVAX
described in Section 14.2, rates of seroprotection to hepatitis A were similar
between the two groups who received VAQTA with or without M-M-R II and VARIVAX.
Measles, mumps, and rubella immune responses were tested in 241 subjects, 263
subjects, and 270 subjects, respectively. Seropositivity rates were 98.8% [95%
CI: 96.4%, 99.7%] for measles, 99.6% [95% CI: 97.9%, 100%] for mumps, and 100%
[95% CI: 98.6%, 100%] for rubella, which were similar to observed historical rates
(seropositivity rates 99% for all three antigens, with lower bound of the 95%
CI > 89%) following vaccination with a first dose of M-M-R II in this age
group. Data from this study were insufficient to adequately assess the immune
response to VARIVAX administered concomitantly with VAQTA. In this same study,
the second dose of VAQTA at 18 months of age was given with or without Tripedia
(DTaP). Seropositivity rates for diphtheria and tetanus were similar to those
in historical controls. However, data from this study were insufficient to
assess the pertussis response of DTaP when administered with VAQTA. Rates of
seroprotection to hepatitis A were similar between the two groups who received
VAQTA with or without M-M-R II and VARIVAX, and between the two groups who
received VAQTA with or without DTaP.
Clinical Studies of VAQTA with ProQuad and Prevnar
In the clinical trial of concomitant use of VAQTA with
ProQuad and pneumococcal 7-valent conjugate vaccine in children 12 to 15 months
of age described in Section 14.2, the antibody GMTs for S. pneumoniae types 4,
6B, 9V, 14, 18C, 19F, and 23F 6 weeks after vaccination with pneumococcal
7-valent conjugate vaccine administered concomitantly with ProQuad and VAQTA
were non-inferior as compared to GMTs observed in the group given pneumococcal
7-valent conjugate vaccine with ProQuad alone (the lower bounds of the 95% CI
around the fold-difference for the 7 serotypes excluded 0.5). For the varicella
component of ProQuad, in subjects with baseline antibody titers < 1.25
gpELISA units/mL, the proportion with a titer ≥ 5 gpELISA units/mL 6 weeks
after their first dose of ProQuad was non-inferior (defined as -10 percentage
point change) when ProQuad was administered with VAQTA and pneumococcal
7-valent conjugate vaccine as compared to the proportion with a titer ≥ 5
gpELISA units/mL when ProQuad was administered with pneumococcal 7-valent
conjugate vaccine alone (difference in seroprotection rate -5.1% [95% CI: -9.3,
-1.4%]). Hepatitis A responses were similar when compared between the two
groups who received VAQTA with or without ProQuad and pneumococcal 7-valent
conjugate vaccine. Seroconversion rates and antibody titers for varicella and S.
pneumoniae types 4, 6B, 9V, 14, 18C, 19F, and 23F were similar between groups
at 6 weeks postvaccination.
Clinical Studies of VAQTA with INFANRIX and PedvaxHIB
In the clinical trial of concomitant administration of
VAQTA with INFANRIX and PedvaxHIB in children 15 months of age, described in
Section 14.2, when the first dose of VAQTA was administered concomitantly with
either INFANRIX and PedvaxHIB or PedvaxHIB, there was no interference in immune
response to hepatitis A as measured by seropositivity rates after dose 2 of
VAQTA compared to administration of both doses of VAQTA alone. When dose 1 of
VAQTA was administered concomitantly with either PedvaxHIB and INFANRIX or
PedvaxHIB, there was no interference in immune response to Haemophilus
influenzae b (as measured by the proportion of subjects who attained an
anti-polyribosylribitol phosphate antibody titer > 1.0 mcg/mL at 4 weeks
after vaccination), compared to subjects receiving either PedvaxHIB and
INFANRIX or PedvaxHIB. When VAQTA was administered concomitantly with INFANRIX
and PedvaxHIB, there was no interference in immune responses at 4 weeks after
vaccination to the pertussis antigens (PT, FHA, or pertactin, as measured by
GMTs) and no interference in immune responses to diphtheria toxoid or tetanus
toxoid (as measured by the proportion of subjects achieving an antibody titer
> 0.1 IU/mL) compared to administration of INFANRIX and PedvaxHIB.
Clinical Studies of VAQTA with Typhoid Vi Polysaccharide
Vaccine and Yellow Fever Vaccine, Live Attenuated
In the clinical trial of concomitant use of VAQTA with
typhoid Vi polysaccharide and yellow fever vaccines in adults 18-54 years of
age described in Section 6.1, the antibody response rates for typhoid Vi
polysaccharide and yellow fever were adequate when typhoid Vi polysaccharide
and yellow fever vaccines were administered concomitantly with (N=80) and
nonconcomitantly without VAQTA (N=80). The seropositivity rate for hepatitis A
when VAQTA, typhoid Vi polysaccharide, and yellow fever vaccines were
administered concomitantly was generally similar to when VAQTA was given alone [see
DRUG INTERACTIONS].
Data are insufficient to assess the immune response to
VAQTA and poliovirus vaccine when administered concomitantly.
REFERENCES
6 The clinical case definition included all of the following
occurring at the same time: 1) one or more typical clinical signs or symptoms
of hepatitis A (e.g., jaundice, malaise, fever ≥ 38.3°C); 2) elevation of hepatitis A IgM antibody (HAVAB-M); 3)
elevation of alanine transferase (ALT) ≥ 2
times the upper limit of normal.
7 One vaccinee did not meet the pre-defined criteria for clinically
confirmed hepatitis A but did have positive hepatitis A IgM and borderline
liver enzyme (ALT) elevations on days 34, 50, and 58 after vaccination with
mild clinical symptoms observed on days 49 and 50.