[Letter to Daniel K. Inouye from Anthony Fauci]

DEPARTMENT OF HEALTH & HUMAN SERVICES - ~ - - e
4.,National Institutes of Healtr
National Institute of Allergy
and Infectious Diseases
Bethesda. Maryland 20892
May 10, 1991
The Honorable Daniel K. Inouye
United States Senate
Washington, DC 20510-1102
Dear Senator Inouye:
This letter is in response to your inquiry of April 16, regarding the National
Institute of Allergy and Infectious Diseases' (NIAID) testing of candidate
vaccines for AIDS, particularly phase II and III clinical trials.
Your inquiry is a very timely one. The issue of phase II/III-AIDS vaccine
clinical trials is very complex, and one that has been considered by various
groups of experts over the past year, most recently on April 29 by the
National Institutes of Health (NIH) AIDS Program Advisory Committee. [A
partial listing of other recent meetings convened by the NIAID and other
parties to address vaccine research and development issues is enclosed.]
Two very important considerations impact the decision to conduct of Phase
II/III vaccine trials: 1) These trials in humans are extremely costly; and
2) require the participation of a large number of uninfected individuals who
are at high risk for exposure to HIV. Because of cost considerations and the
recognition that the defined populations in which to test vaccines are
limited, we would thus want to test only those vaccine candidates that show
the most promise of inducing protective immunity. The determination of what
criteria to use to identify such promising candidates before moving ahead into
phase II/III efficacy studies in humans has been the focus of a considerable
degree of recent scientific discussion.
Based on the specific recommendations of two distinguished groups of experts
and the general consensus among those working in the field of vaccine research
and development, the NIAID made a decision that before proceeding to phase
II/III efficacy trials in humans, there must be compelling evidence of
immunogenicity and protection shown in animal studies. Accordingly, the NIAID
has chosen to emphasize the use of animal models to test the efficacy of
candidate vaccines under study before selecting one or more candidate vaccines
for large scale efficacy trials in humans.
Given the urgency of this epidemic, let me assure you that we will continue
our efforts to resolve the issues at hand. We are, in fact, in the process of
developing a plan that will address not only these issues, but the overall
aspects of AIDS vaccine development.

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