It is certainly the case that the kinds of options that are available to subjects in Western democracies make it easier to equate freedom with autonomy. But this does not mean that it is impossible to create such conditions in developing nations that have poor healthcare. The problem is that it is very expensive to do so without the infrastructure that comes with a national healthcare system that is properly funded. If trial organizers had promised all the women entering the trial the most effective dose of AZT to block transmission, and then had asked if any women, out of altruism, would like to be randomized into low or high treatment arms - and leaving out the placebo arm, without putting any pressure on them to do so, we would see the kind of trial in which freedom, autonomy, and the chance for survival were maximized. It is easy to imagine trial investigators and drug company economists shaking their heads at the cost of such a trial.
Drug companies have much to gain in the short term from a successful trial.
Unfortunately ethical practice is often expensive. However, here the principle researcher refused to allow a placebo arm, using instead a high and low dose group and comparing results. While the trial is still somewhat ethically vexed. All the women on this trial received some treatment. I am indebted to Ms. Lynn Gillam for this insight.