AZT: European Study Stopped, Disease Progression Reduced

A major European/Australian study comparing AZT to placebo in
almost one thousand patients was halted recently after a preliminary
analysis showed that those receiving the drug were less than half as
likely to progress to illness or low T-helper count as those receiving
the placebo.
In what may be the most significant result of this study, AZT was
found to work at least as well for asymptomatics who had high T-helper
counts (500-750) when they began the study, as for those with lower T-
helper counts. Of those who entered the study with counts between 500
and 750, 18% of those assig\J& to placebo progressed to an "endpoint"
(either HIV-related illness, or T- helper count below 350), vs. 9% of
those randomly assigned to AZT. Of those with T-helper count between
400 and 500 at entry, 38% of those given placebo progressed, compared to
20% of those given AZT. [Note: this data, first analyzed by a Data
Safety Monitoring Board, was provided in a February 3 press release by
Burroughs-Wellcome.]
The dose used, 500 mg twice daily, was twice the standard U. S.
dose; the dose was reduced to 250 every 12 hours (equivalent to the U.
S. dose) if side effects developed. With this regimen, there was no
difference in severe side effects reported between AZT and placebo, in
these relatively healthy patients. [Note: There is no reason to believe
that the large dose used in this study was necessary. Major U. S.
studies have found no additional benefit from using over 500 mg per day.
The only reason for the large dose is that this trial started in
December 1988, when higher doses were in general use.]
Note that this study is not the well-known "Concorde" AZT study,
which is still ongoing in Europe. The two studies are in different
patient groups. In the Concorde study, about two thirds of the
participants had T-helper counts less than 500 at entry; in the study
reported here, about three fourths had T- helper counts more than 500.
Comment
This study will probably support the growing belief among some AIDS
experts that antiviral treatment should begin as early as possible -- as
soon as one knows one is HIV positive -- regardless of T-helper count.