Although HIV infection is still impossible to cure, we do have some treatments that improve quality of life of the patients and their life expectancy. However, scientists are noticing a worrying phenomenon – many HIV patients in Africa started showing signs of multidrug resistance. A new UCL study showed that these patients, who showed resistance to older generation drugs, are also resistant to modern drugs.
There were 712 HIV patients from across the world included in the study, and all of these cases of HIV were not controlled by antiretroviral drugs. There are two types of drugs that were taken into account in this research – thymidine analogues, which are older generation drugs, and tenofovir, the main drug in most modern HIV treatment and prevention strategies. Rather worryingly, scientists found that 16% of people who are resistant to modern treatments did not respond to thymidine analogues either. And even 80 % of those who were not responding to thymidine, were resistant to tenofovir treatment.
This surprised scientists, because they thought being resistant to both drugs is not that much possible. In other words, science previously considered mutations for thymidine analogue resistance to be incompatible with mutations for tenofovir resistance. From now on it will absolutely necessary to check genetic profile of the virus before prescribing first-line treatments. How do patients develop the resistance to drugs? Scientists think it is partly their own fault – people with HIV are not taking their drugs regularly enough and that allows the virus to develop the resistance.
Scientists will now think about affordable testing kits that would allow checking for multidrug resistance before prescribing the treatment. Professor Ravi Gupta, lead author of the study, said: “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”. If first line medicine fails to deliver its effect, doctors will have to resort to the second line treatment, which is not available everywhere, is more expensive and causes greater side effects.
These are very worrying news. However, it is also very good that scientists managed to detect this phenomenon early and now can find innovative ways of addressing it.