ACTG 315 Preliminary Results: Drug Cocktail Restores Partial Immune Function

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award to establish the ACTG Immunology Advanced Technology Laboratories. This network of
16 immunology laboratories has since set up standardized immunologic assays and now serves
the ACTUs that comprise the ACTG. "ACTG 315 is the Irst field-test of this new scientific
capability within the ACTG," comments NIAID's Lawrence Fox, M.D., Ph.D., medical officer in
the Division of AIDS HIV Medical Research Branch.
"'The significance of this study," says Dr. Lederman, " is that it will give us real clues to
how the immune response recovers after therapy."
ACTG 315 enrolled 53 men and women with CD4+ T-cell counts between 100 and 300
cells per cubic millimeter (mm3) of blood. To be eligible for the trial, they previously must have
tolerated at least three consecutive months of AZT therapy but never have received 3TC or a
protease inhibitor.
After a 35-day washout period during which they took no antivirals, the study
participants began taking ritonavir (Abbott Laboratories) alone, gradually escalating the dose to
600 mg twice a day. Ten days after starting ritonavir, they added three daily doses of 200 mg
AZT (Glaxo Wellcome) and twice-daily doses of 150 mg 3TC (Glaxo Wellcome) to the regimen,
and will remain on this treatment for 48 weeks. Dr. Ledlerman presented the analysis of data
from 33 patients after 12 weeks of treatment.
The data show that the dramatic rise in CD4 counts and fall in plasma levels of virus
seen early after starting HAART are accompanied by partial restoration of the immune
response. It remains to be seen after further treatment, says Dr. Lederman, if prolonged virus
suppression results in greater restoration of immune function.
"ACTG 315 indicates the value of initiating potent antiretroviral therapy early before
significant loss of immune function has occurred," Dr. Lederman concludes. "Our findings also

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