AZT

The use of AZT for the treatment of asymptomatic HIV-positives

In View of the reported 'success' of AZT as AIDS therapy, the drug was also tested for licensing to prevent AIDS in healthy HIV-positive persons.  Burroughs Wellcome used the same scientists including Fischl, Richman, and Volberding (Volberding et al., 1990) who had tested AZT as a treatment for AIDS.  The study treated AIDS-free, HIV-positive 25 to 45 year old male homosexuals and intravenous drug users with "fewer than 500 T-cells" for one year either with AZT or with a placebo.  There was no attempt to match the three groups for frequency of drug use.

The study reports AIDS diseases in:

               1) 11 out of 453 on 500 mg AZT per day

               2) 14 out of 457 on 1500 mg AZT per day

               3) 33 out of 428 on a placebo (Volberding et al., 1990).

The AZT-groups appeared to do better than expected and the placebo group did as expected.  Therefore, it was claimed that AZT prevents AIDS.
 

 One year study of AZT as an AIDS preventative

However, the price for the presumed savings of AIDS cases with AZT, compared to the placebo group, was high because 19 AZT-specific cases of potentially fatal anemia, neutropenia, and severe cases of potentially fatal anemia, neutropenia, and severe nausea appeared in the 500 mg AZT-group, and 72 such cases including 29 anemias requiring life-saving blood transfusions, appeared in the 1500 mg AZT-group.  Although the blood abnormalities were not diagnosed as AIDS, neutropenia generates immunodeficiency (Walton, et al., 1986) and thus AIDS.  If these AZT-specific cases were included in the calculation of benefits from AZT compared to the placebo group, the 500 mg group no longer benefited and the 1500 mg group tripled its disease risk.

The authors of this study have recently reevaluated their data and come to the conclusion that AZT does not prevent AIDS (Lenderking, et al., 1994; Hughes, et al., 1994).

Data from the AIDS Clinical Trials Group (NIAID Backgrounder, June 28, 1993) again shows that AZT treatment of asymptomatic individuals (along with blood transfusions and other concomitant medications) initially slows down the progression of AIDS or death, but that after four years, it results in more AIDS and death.  This is obvious from the following figure:

By the end of the study period, the following results were observed.  In the untreated group, 25.5% (106 out of 415) either came down with AIDS or died and in the AZT-treated group, 33.0% (303 out of 918) either came down with AIDS or died.  Also of note is that the progression of AIDS or death at the end of the study period began to level off among those who were untreated, whereas among AZT-treated individuals, it began to plummet.  With these results, one wonders why the study was not continued.

In April 1994, the Lancet published the results of the British-French Concorde Study undertaken to test whether AZT would prevent AIDS in 877 healthy HIV-positive men; another 872 healthy HIV-positive men were untreated.  When the study was over 96 of the 850 or 10.9% of the AZT-treated men had died whereas only 76 of the 872 or 8.7% of the untreated men had died.
 

Part 4: Some harmful effects of AZT disappear after it is discontinued