Sub-type of HIV prevalent in many resource-limited countries more prone to NNRTI resistance

Michael Carter
Estimated reading time 1 minutes
This article is more than 22 years old.

The use of HAART regimens containing non-nucleoside reverse transcriptase inhibitors (NNRTIs) in areas where HIV-1 sub-type C is common may be less successful than in Europe and North America, if the results of a study published in Antimicrobial Agents and Chemotherapy are borne out in larger-scale trials.

Investigators studied untreated HIV-positive Ethiopians who had migrated to Israel. They detected many ‘silent mutations’, or secondary mutations, in the sub-type C virus they were infected with, suggesting that resistance to NNRTIs would emerge rapidly. In one patient, a mutation at G190A in the reverse transcriptase was noted, which confers high levels of resistance to nevirapine. Laboratory studies found that sub-type C virus resistant to all the currently available NNRTIs emerged much more easily and rapidly than NNRTI resistant sub-type B virus. In addition, the investigators found some previously undetected resistance mutations to NNRTIs in sub-type C HIV.

Sub-type C of HIV is the most common strain of HIV in Ethiopia, as well as other areas with high rates of HIV infection including Southern Africa, India and parts of China. Given their easy dosing requirements, NNRTIs are favoured in treatment strategies in resource limited countries, including areas where sub-type C is most prevalent. Most clinical trial data, however, concern the use of NNRTIs in people infected with sub-type B, the prevalent form of HIV-1 in western Europe and north America.

Glossary

reverse transcriptase

A retroviral enzyme which converts genetic material from RNA into DNA, an essential step in the lifecycle of HIV. Several classes of anti-HIV drugs interfere with this stage of HIV’s life cycle: nucleoside reverse transcriptase inhibitors and nucleotide reverse transcriptase inhibitors (NRTIs) and non-nucleoside reverse transcriptase inhibitors (NNRTIs). 

chemotherapy

The use of drugs to treat an illness, especially cancer.

strain

A variant characterised by a specific genotype.

 

nucleoside

A precursor to a building block of DNA or RNA. Nucleosides must be chemically changed into nucleotides before they can be used to make DNA or RNA. 

clinical trial

A research study involving participants, usually to find out how well a new drug or treatment works in people and how safe it is.

Reference: Loemba H et al. Genetic divergence of human immunodeficiency virus type 1 Ethiopian clade C reverse transcriptase (RT) and rapid development of resistance against nonnucleoside inhibitors of RT. Antimicrobial Agents and Chemotherapy 46: 2087-2094, 2002.

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