Subject: Immune Cell Levels Gain Significance In AIDS-Drug Study
Date: Published: 8/2/91 (55 lines)
Source: Wall Street Journal. Copyright Dow Jones & Co. Inc.

    Technology:
    Immune Cell Levels
    Gain Significance
    In AIDS-Drug Study

    BETHESDA, Md.  -- The importance of immune-system cells in
 AIDS patients in measuring the value of new antiviral drugs
 got a boost in a new federal study of the epidemic.
    The findings came in a retrospective analysis by
 researchers from the National Cancer Institute and the
 Harvard University School of Public Health.  The researchers
 looked at what happened to 55 acquired immune deficiency
 syndrome patients treated between 1985 and 1990 with the
 Wellcome PLC drug AZT.  
    The study found that all but one of the 44 deaths in the
 group so far occurred when the patients' infection-fighting
 T4 cells had fallen below a level of 50 cells per cubic
 centimeter.  Normal levels are about 1,000 or more, but AIDS
 causes a gradual depletion of these immune sentry cells.
    T4 cells are a type of white blood cell that are a main
 part of the immune system.
    The study adds to a growing consensus that such markers of
 immune-system health may serve as an alternate measure of
 drug effectiveness.  Historically, the Food and Drug
 Administration has demanded proof that a drug produced a
 longer or better-quality life for patients.
    Study leader Robert Yarchoan of the National Cancer
 Institute emphasized that falling below 50 T4 cells isn't an
 automatic death sentence, as most patients continued to have
 median survival of a year and some lived three times that
 long.  However, it is considered a "hazard level," according
 to a report of the study published in today's edition of the
 Annals of Internal Medicine.
    Carl Peck, head of the FDA's Center for Drug Evaluation
 and Research, said the study strengthens the case for using
 immune markers in clinical trials.  Recently, T4 cell levels
 were a major reason for a panel recommendation of FDA
 approval for Bristol-Myers Squibb Co. 's drug DDI. 
    "This looks interesting," Dr. Peck said of the report.
 "It's certainly part of the {evidence} that has persuaded us"
 of the significance of T4 cells.  However, he declined to
 predict whether the study would affect the outcome of pending
 drug applications such as Roche Holding Ltd.'s for its AIDS
 drug DDC. Dr. Peck added that the idea of using the level of
 50 cells per cubic centimeter as "a landmark" of disease
 progression needs to be confirmed in other studies.

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