The Potential Use of HIV Vaccines for the Treatment of HIV Infection: Scientific Summary of the State-of-the-Art

4. Multi-site trial in Canada

A placebo-controlled, randomized trial of the MGS gpl60 (LAI) vaccine in
HIV seropositive patients with CD4+ T-cells >500/mm3, and not receiving
antiretroviral therapy. Trial has enrolled 280 patients and is closed
to accrual. The endpoints of the study are clinical.
Pediatric Therapeutic Vaccine Research
There are two broad goals of the HIV vaccine effort encompassed within the
pediatric agenda of DAIDS: 1) post-infection therapy for HIV+ children using
the therapeutic vaccination approach also being studied in adults and 2) the
prevention of perinatal HIV transmission. These goals are being approached in
several ways in pediatric populations as well as in HIV+ pregnant women.
These include active immunization of HIV positive children with the intent of
altering favorably the course of disease, immunization of children born to HIV
positive women at birth with the intent of reducing transmission or altering
disease, and immunization of HIV positive pregnant women in order to reduce
the risk of transmission of virus from mother to infant and/or to stabilize
the mother's disease. Ultimately, this vaccination strategy may lead to
immunizing HIV negative children with the intent of preventing infection with
HIV later in life or immunizing HIV positive women of childbearing age with
the dual goals of a therapeutic strategy for the woman and prevention of
infection for the child. It is anticipated at this time that pediatric
prevention strategies will likely need to include interventions with both
active and passive immunization.
The above aims are distinct but interrelated. Efficacy trials designed to
test any of the above modalities require a systematic background of Phase I/II
studies in HIV+ pregnant women and in infants and children, both HIV negative
and positive.
Active Immunization in Pregnancy: Currently there are three parallel trials
involving the immunization of pregnant women who are HIV+, planned as an
AVEG/ACTG collaborative effort (TABLE 12). They are all multi-center, double
blind, placebo controlled, Phase I studies to evaluate the safety and
immunogenicity of multiple injections of a single immunogenic dose of
envelope-derived HIV subunit vaccines in HIV-infected, asymptomatic, pregnant
women. Women will be enrolled between 16 and 24 weeks gestation at the time
of their initial vaccination and given booster immunizations monthly
thereafter. The total number of women in each study is anticipated to be 24,
16 active immunization vaccinees and 8 adjuvant only vaccinees. Patients will
be stratified for Zidovudine use during the pregnancy and there is an entry
criteron of having CD4+ T cells >400 cells/mm3. Mother and infant will be
followed for 18 months after the child's birth. Study endpoints will examine
maternal/fetal/infant safety issues as well as maternal immunization effects
(viral and immunologic parameters) and an evaluation of the health and
infection status of the infant.
These trials will include the use of the MicroGeneSys recombinant gpl60
derived from the envelope sequence of HIV-1/LAV in a baculovirus vector

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