Medical Chronicle recently hosted part two of an HIV drug resistance series. The topic of this webinar was understanding HIV drug resistance through case studies. It was sponsored by Thermo Fisher Scientific and presented by Dr Kay Mahomed and Bronwyn Bosch.
To watch a replay of this webinar, go to: https://event.webinarjam.com/go/replay/630/pl64luxm6awqxuvrosq. You will still earn your CPD point.
The following article is based on key takeaways from the presentation of case studies. HIV drug resistance is a result in the change in the HIV genetic structure. With this, there's impaired ability of antiretroviral therapy (ART) to prevent replication of that HIV virus. It can be either acquired- or pre-treatment drug resistance. This compromises the efficacy of the regimens that we have available in that if patients are not suppressed, they're at a higher risk of HIV-associated morbidity and mortality.
The results of HIV drug resistance tests inform the selection of our standard first and often second-line ART regimens.
In Nucleoside/nucleotide reverse transcriptase inhibitors (NRTIs) we assume there is going to be resistance and we really don't look at them for the second- and third-line treatment because we know that the genetic barrier to resistance is not as strong as some of the other agents we have available. Dosing schedule is so important for our patients. If you are in private practice and you have options and patients can self-fund, sometimes that is the way to go, and patients will suppress well on once-daily regimens. We ideally would like to choose the drugs with the lowest level of resistance, but we also do have dolutegravir to boost that regimen, which can be the case in NRTIs.
Think about the side effects of the regimen you are prescribing. If we have a resistance panel, through resistance testing, we can tailor the drugs based on side effects.
In terms of mother to child transmission, it's important to remember that the mother is a patient throughout that whole journey. We can't just stop in pregnancy when we see that the patient is nicely virologically suppressed. There is still the risk of transmission even after that period, for a variety of reasons. It is crucial to test HIV drug resistance on infants who have been exposed to HIV or who are infected with HIV. There is quite a high level of transmitted resistance from mother to baby.
The importance of adherence cannot be overemphasised. Develop relationships with your patients where possible to try and figure out how to assist, where possible, in changing from a twice- to a once-daily dosing.