HIV drug resistance study highlights need for viral load tests, affordable second line treatments

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CIDCoverA study across southern Africa following more than 2700 people with HIV showed that before their treatment even began, more than 5 percent had viruses that were resistant to at least one of the first line of drugs used to treat HIV, necessitating a switch to a second, less accessible and more expensive treatment. Authors of the study, Pretreatment HIV Drug Resistance Increases Regimen Switches in Sub-Saharan Africa, note that the numbers of people found to have acquired strains of HIV that do not respond optimally to one or more of medicines used to start treatment can be expected to grow, as more people start antiretroviral treatment in the next few years. The findings, published in Clinical Infectious Diseases, underscore needs for greater access in Africa to testing to monitor patients’ viral load as a measure of treatment effectiveness, and to more affordable second-line HIV treatments, authors noted.

The results of the study, which took place across 13 health facilities in six countries, examined the role of “pretreatment drug resistance” on patients’ need to switch from first to second-line therapies, and on HIV-related illnesses and deaths. While the study found that nearly 14 percent of the patients followed had HIV with drug-resistant mutations, genotyping of the viruses indicated that the drug-resistant strain had been transmitted in 5.5 percent of all cases. While the study, which followed participants at all of the sites for two years, and at five sites for three years, did not find a correlation between pretreatment drug resistance and numbers of HIV-related illnesses and deaths, study authors note that impacts of pretreatment drug resistance on health could be expected to show in longer than the time the patients were followed. In addition, because genotyping that led to classifying drug resistance as pretreatment relied on identifying known mutations, it is possible that more of the patients followed had strains of virus that were resistant  before treatment but had not been identified.The authors, led by T. Sonia Boender of Amsterdam Institute of Global Health and Development, conclude that pretreatment resistance threatens sustainable HIV treatment success and highlights the need for improved access to tests to monitor treatment effectiveness and to affordable treatments for viruses not effectively treated with first line medicines.

While monitoring patients’ viral loads is considered the best way to confirm that treatment is working, access to viral load testing remains limited across Africa, the authors note. In addition, they point to costs for second line drugs — more than twice the cost of first-line drugs — and for third-line drugs — about 15 times the cost of first-line drugs — that will further stretch limited resources available for expanded HIV treatment access.

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