AIDS Vaccine Panel Discussion [Minutes]

7-APR-97 PACHA AIDS VACCINE PANEL DISCUSSION - p. 9

We have a model of working with host partners, countries, and industry. It's worked
effectively in the past for the development of a number of vaccines. Most recently, it's
resulted in the licensure of a hepatitis A vaccine based upon a pivotal trial that was
conducted in Thailand. For HIV, we have a strategy where we are intending to
evaluate specific relevant immune effector mechanisms, select the best candidate
vaccine in each specific immune effector class, and try to move these forward ideally,
as a goal, in a multi-arm comparative trial.
The next frame, again, builds on this. It describes, like malaria, that we are
building trials based on plausible immune effectors of virologic control, we'll select
candidates that induce indicated responses, and we'll conduct head-to-head trials.
The next frame just breaks it down and reduces it to practice. This is what we
actually have planned in Thailand with two company partners, Chiron Vaccines and
Pasteur-Merieux.
The final page, the last frame, is the thought that I'd like to leave you with the
most. It's a phrase that was taken out of Science magazine in 1994. It states, "In the
absence of predictive animal models or reliable immune indicators of protection, studies
to assess the efficacy of vaccines must be confined to placebo-controlled trials in
humans who are intensively evaluated after adequate immunization." This was
describing one in a long series of efficacy trials of a rotavirus vaccine in 1982, and at
last count I believe there were 14 efficacy trials for rotavirus vaccines.
So we do need to get products into the distal end of the pipeline. It's the only
way, I think, that we're going to ever get hard data on whether or not approaches will
work, and it will also help us to validate some of the laboratory parameters that we're
currently using and sometimes overrelying upon in making decisions about whether to
advance candidates to advanced development or not.
Okay. On to the recommendations.
DR. LEVINE: You have about a minute to do that.
DR. McNEIL: Okay. That's all it will take for me, I think. You actually, Dr. Levine, passed
on four recommendations you wanted us to comment on. The first recommendation I
would rephrase to say that three distinct vaccine strategies, first-generation strategies,
would be fully evaluated by the year 2005. I think saying that a vaccine will be
developed, it's very unclear what that means. I think it's much more clear if we say
three distinct approaches which are first-generation would be fully evaluated.

In terms of the second recommendation on funding, more funding could be