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Study Finds High Prevalence of Multidrug-resistant HIV

DEC 07, 2016 | EINAV KEET
While multidrug-resistant forms of infections, such as tuberculosis, have become a growing problem for people with HIV, a new study from the United Kingdom shows that a significant number of HIV patients have a form of the virus that is, itself, resistant to antiretroviral drugs.

According to the World Health Organization (WHO), more than 36 million people were living with HIV at the end of 2015, and, in that year, about 1.1 million people died from HIV-related causes around the world. Nearly two-thirds of the global population living with HIV are in sub-Saharan Africa. Public health efforts and better access to antiretroviral drugs to control the virus and prevent disease transmission have improved global HIV rates, as new infections dropped by 35% from 2000 to 2015 and AIDS-related deaths declined by 28% during that time period, saving about 8 million lives.

However, the HIV virus has mutated due to increased exposure to antiretroviral treatments, and increasing rates of drug resistance threatens to undo the progress made over recent decades to fight the HIV/AIDS epidemic. Drug-resistant HIV has led to more treatment failure as well as the spread of these hard-to-treat forms of the virus, and a WHO report from earlier this year warned of the increasing global trend of HIV drug resistance. In response, the health agency is developing a five-year global action plan to combat the growing problem and keep progress on the HIV epidemic moving on-track toward reaching target goals.

A recent investigation conducted by researchers at the University College of London studied cases involving people with HIV whose infections were not responding to antiretroviral drugs. Their findings were published in The Lancet Infectious Diseases. The research team studied a total of 712 patients in a retrospective study covering data collected from 2005 to 2013 on drug resistance among HIV patients who were receiving antiretroviral drug therapy. The older generation of these drugs consists mostly of a group called thymidine analogues, but the study noted that in 2012 WHO recommendations shifted toward treatment substitution with the newer first-line drug, tenofovir, to prevent and treat HIV.

The researchers found that 16% of patients whose HIV infections were unresponsive to today’s first-line medications had thymidine analogue mutations, mutations in the genetic structure of the HIV virus that allow for resistance to thymidine analogues drugs. Of those patients, 80% also showed resistance to tenofovir. “We were very surprised to see that so many people were resistant to both drugs, as we didn’t think this was possible,” explained lead author Ravi Gupta, MPH, in a recent press release. “Mutations for thymidine analogue resistance were previously thought to be incompatible with mutations for tenofovir resistance, but we now see that HIV can be resistant to both at once. This emphasises the need to check the genetic profile of patient’s virus before prescribing first-line treatments, as they may have already developed resistance to other treatments that they did not mention having taken.”

At least 85% to 90% of the time, drug-resistant HIV occurs as a result of a patient not taking their medication regularly, noted the study authors. If a patient does not take antiretroviral drugs as advised, the virus can develop resistance, often to a number of drugs. Once a patient is resistant to first-line drugs, their only option is more expensive second-line drugs, which are not always accessible.

“To prevent these multi-resistant strains from developing, we need cheap, reliable systems to assess people before treatment,” noted Dr. Gupta. “Ideally, we need simple resistance testing kits to help screen for drug resistance before giving treatment. This would also help us to monitor HIV drug resistance globally more effectively. However, until such kits are widely available, we could test the amount of virus in the bloodstream before and after giving treatment. Although not as precise as resistance testing, this could help us to detect treatment failure earlier and switch patients to second line drugs.”
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