Why don't we have a cure for AIDS yet?

By Michael Edmonds 03/12/2011

Last week I came across this article which describes how the number of people living with AIDS has increased due to better access to drugs which fight HIV. A fairly reasonable article … But then I made the mistake of reading some of the comments (I know, I know, I should know better) where several misconceived and ill informed opinions were circulating including the suggestion that drug companies are not interested in finding a cure – rather they are only interested in drugs that prolong life so they could profit over long periods of time.

While I can understand that such misguided views could easily arise from the frustration at the perceived slow progress of science, and the fact that pharmaceutical companies have a less than pure reputation, the real reason why a cure has not been found is due to the complexity of the science involved.

Indeed when the Human Immunodeficiency Virus (HIV) was first identified in 1983 many scientists mistakenly thought that a cure would be developed within a decade. Sadly, the virus has proven much more difficult to deal with than first imagined, for several reasons:

1) Virus reservoirs

Many drugs are limited to where they can get to in the human body. This means that some of the virus can “hide” out of range of anti-HIV drugs (similar problems can occur with anticancer treatments as well). The blood- brain barrier is a good example of this – while HIV concentration in the blood can be reduced to undetectable levels, most drugs cannot cross the barrier between the brain and the circulatory system. While such virus particles remain untouchable, HIV cannot be eradicated from the body

2) Mutation

HIV is an extremely adaptive virus due to it’s relatively high level of mutation. Given time the virus is capable of mutating into forms that are resistant to some of the current drugs used to treat it.

3) Complexity of Drug Design and Development*

The design and preparation of new drugs is a much more complex process than most people realise. Typically it involves preparing and testing hundreds of thousands of different compounds looking for the one compound that not only inhibits the virus in a testtube/petri dish, but which is also soluble, not too toxic, not too readily metabolised by the body, and not too difficult to prepare in reasonable quantities. This is a time consuming process which has at least lead to a number of drugs which, although not cures, have increased the live span and the quality of life for many of those infected with HIV.

However my strongest argument against those who believe that pharmaceutical companies are not trying to cure HIV (or are hiding cures for it) is that scientists who work for pharmaceutical companies are not robots but living, feeling people. Many will know personally of people who have died from AIDS and are doing all the can to defeat this complex and “cunning” adversary. Furthermore, scientists are interested in advancing knowledge** – the very idea of hiding a cure from the public is the very anathema of what science is all about.

* As well as drugs, initially it was hoped that a vaccine might prove effective in preventing HIV infection. However, so far, a suitable vaccine has not yet been achieved.

** A survey of NZ Scientists and Technologists shows that the two biggest reasons for becoming a scientist/technologist were “the search for knowledge/truth” and “the desire to improve the human conditions”.

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