Statement of Cathy Wilfert, Scientific Director, Pediatric AIDS Foundation

101086/1997 12:32 9199680447 WILFERT PAGE 03
9-22-1997 10:49AM FROM PEDIATRIC AIDS 3103931882 P. 2
intervention to decrease maternal-to-inf ant transmission in developing
nations. These representatives of the world community decided that the 076 -AZT regimen could not be recommended globally because it was not
logistically or economically feasible. The persons representing developing
nations felt they must decide what was best for their nations and they did so.
A consensus opinion stated that any clinical trial must study interventions
which could be implemented in these nations. It is known that most mother
to infant transmission occurs around the time of delivery, and therefore
short-term therapy administered around the time of delivery might reduce
transmission.
The question to be addressed was what feasible interventions will be
effective in these developing nations? The question was not what
intervention will be as effective as the 076-AZT regimen. The consensus of
those at the WHO conference was that any proposed intervention must be
compared to existing transmission rates which were occurring in the absence
of any available therapy. Therefore, the conference representatives decided it
was appropriate to use no therapy (or placebo) as part of such studies to find
an effective applicable intervention. A significant reduction in transmission
will be defined most efficiently with the comparison of treatment to no
treatment. If one treatment is compared to another treatment, e.g. to the 076 -AZT regimen, and does not reduce transmission to the same extent, what
does this mean? Is this treatment no good at all or is it partially effective? If
there is a comparison to "historical controls" (rates observed in the past) one
must consider whether any other factors (for example, a change in
breastfeeding practices) could be influencing transmission rates. There is a
possibility that such a treatment would be less effective than the 076-AZT
regimen and therefore not be perceived as successful. The trial would have
been completed. An intervention which in fact was effective to a lesser extent
than the 076-AZT regimen could be discarded. Infants in the trial would
benefit which is wonderful, but after the trial, no therapy would be available
to any one. Suppose two treatments are compared and the transmission rates
are identical in the two groups. It takes a larger number of participants to be
sure the numbers are the same. In addition, let us suppose one treatment is
the 076-AZT regimen (if the trial could be done) but the rate of transmission
from mother to child is higher than that observed in the U.S. How will it be
determined that transmission has been reduced by either treatment? Will a
comparison be possible with "historical controls," with transmission rates in
other countries or other populations? Can one be confident these are
effective interventions and recommend nationwide implementation?
The consensus group continues to meet several times per year to
discuss these trials. There has been a recent review and affirmation of the
ethics of these studies confirming the science of these studies. Nevertheless,

there are those who feel that because it is not ethical to conduct a placebocontrolled perinatal intervention trial in any nation such as the U.S. with