AZT was the first breakthrough in the treatment of AIDS (acquired immune deficiency syndrome), a failure in the immune system caused by HIV (human immunodeficiency virus). Over the years, other anti-AIDS drugs were discovered that work by mechanisms that differ from AZT, at other stages in the virus’s life cycle. Additionally, such drugs could be taken in combination with AZT.
Although there are significant benefits associated with taking multiple anti-AIDS drugs, there are also many problems that rapidly multiply when three or four different drugs are taken each day. To work best, each drug must be taken at carefully specified times, and as might be anticipated, these times and their frequency differ for each drug. Moreover, these medicines cause a wide range of adverse effects, some of which are potentially serious. They can also interact with a bewildering array of other drugs, increasing potential toxicity or reducing effectiveness. To add to these various problems, the cost of many of these drugs is high. For most AIDS patients, multiple drugs are prohibitively expensive.
There are powerful benefits associated with using multiple drugs. Early on, it was recognized that HIV rapidly mutates and can transform itself from being drug vulnerable to drug resistant. However, the use of drugs in combination, which act in different ways, reduces the likelihood of the development of resistance. These combinations have been termed highly active antiretroviral therapy, or HAART, an approach that is recommended for all AIDS patients. A number of pharmaceutical manufacturers joined together, starting in 1996, to combine their individual drugs into single pills that can be taken twice daily. This reduces the likelihood that patients will skip doses, which fosters drug resistance.
FROM DEATH WARRANT TO CHRONIC DISEASE. In 2009, there were some 33 million individuals with HIV/AIDS worldwide—a total that has stabilized in recent years. The number of annual deaths has declined to 2.1 million in 2007, thanks to the available drugs. HAART does not cure AIDS—it must be taken for a lifetime—but it has decreased AIDS-related deaths by 50–70 percent and has transformed AIDS from a death sentence to a chronic disease.
SEE ALSO AZT/Retrovir (1987), Viread (2011).
This scanning electron micrograph is of HIV budding (depicted in green) from a lymphocyte (white blood cell, shown in blue). Treatment of HIV/AIDS involves the combined use of multiple drugs (HAART) that interfere with different phases of the HIV virus life cycle.