Quantifying the long-term impact of zidovudine and other anti-HIV therapies on the survivability of those with clinical AIDS

Objective: To determine the long-term behavior of the clinical AIDS survivability curve for a cohort undergoing anti-HIV therapy and for a comparison cohort undergoing no such therapy. Results: Zidovudine therapy is shown to increase the average longevity of a cohort with clinical AIDS a maximum of 5.7 months. Not only does zidovudine eventually fail to prevent death, evidence is presented that suggests that long-term use of the drug may be counterproductive and actually decs-ease survivability. The analysis herein suggests that to maximize longevity in those with clinical AIDS, zidovudine therapy should be administered for a short period (on the order of several months or less) and then ended. Conclusions: The usual practice in controlled anti-HIV drug trials of prematurely ending the experiment as soon as the drug is shown to significantly increase survivability in those with AIDS is shown to be a mistake. Anti-HIV drugs typically have a negative impact on the immune system, and long-term use of these drugs can actually shorten survivability rather than prolong it. Evidence is presented showing that short-term zidovudine therapy increases longevity in those with AIDS, but long-term continuation of the therapy may actually shorten it.