January 24, 2013
New effective and easy-to-use treatments are responsible for a decline in the number of HIV-infected Western Europeans with resistance to antiretroviral drugs, according to researchers. Between 27 and 32 percent of HIV-infected people were resistant to all treatments in 2000; by 2008, the proportion had dropped to 0.3 to one percent of HIV-infected people.
When HIV becomes resistant, the virus can replicate and cause illness and death. Early one- or two-drug regimens could not suppress HIV over time, and resulted in drug-resistant HIV. Triple therapy regimens, introduced in 1996, were not always effective against the drug-resistant HIV. Early three-pill combinations also were weaker, caused side effects, and required strict adherence. Triple therapies developed in the last 10 years are safer, more potent, and easier to use.
The study reviewed 20,323 people treated with anti-HIV drugs between 1997 and 2008 in seven Western European countries. Study participants were mostly men (74 percent), and 64 percent were infected with HIV subtype B. More than half of the group had taken one- or two-drug therapies for HIV. The participants had taken antiretroviral drugs for a median of 64 months when genotyping of their HIV virus took place. Most participants (80 percent) had a mutated virus that was resistant to at least one of the three main types of antiretroviral drugs.
However, resistance to nucleoside reverse transcriptase inhibitors and protease inhibitors decreased after 2001. Resistance to non-nucleoside reverse transcriptase inhibitors began to fall after 2004. Triple-class resistance started to fall after 2005.
The full report, "Declining prevalence of HIV-1 Drug Resistance in Antiretroviral Treatment-Exposed Individuals in Western Europe," was published online in the Journal of Infectious Diseases (2013; doi: 10.1093/infdis/jit017).