Panel to Review GP160 Vaccine Candidate: Report of the Meeting

Mr. Dobson also endorsed the value of comparing several
vaccine candidate products in a large-scale clinical trial. Such
an approach improves efficiency and would avoid the danger of
putting high expectations on a single product. Even a trial
involving several vaccines could prove wasteful if it is not
carefully planned, he warned. "If we do significant scientific
studies, we will get something out of our $20 million; that's
very important." For instance, obtaining measurements of CD4 cell
levels in such population groups (or in selected subgroups),
although cumbersome, is an undertaking that should be taken into
careful consideration, particularly as alternative, increasingly
consistent simplified methods for obtaining such measurements
become available.
Additional special population considerations. Good arguments
can also be made for conducting HIV vaccine clinical trials in
infants, children, and pregnant women, according to pediatrician
Dr. Diana Wara from the University of California, San Francisco.
Children tend to make good "captured populations" for the sake of
conducting vaccine trials. Moreover, in terms of HIV disease,
infected children tend to develop symptoms rapidly, suggesting
that the clinical efficacy of a therapeutic vaccine could be
assessed relatively quickly if it were being tested in such
populations.
In addition, the ability of candidate vaccines to prevent
HIV transmission could be addressed by testing its impact on HIVinfected pregnant women and their newborn infants. Of course,
such studies would leave doubts about extrapolating results to
adult populations, Dr. Wara noted. Nonetheless, several phase I
clinical trials using several different vaccine products are
being planned for populations of pregnant women and of newborn
children, and they are expected to begin by mid 1993.

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