Drug resistance after cessation of efavirenz-based antiretroviral treatment started in pregnancy

HIV drug resistance in the era of contemporary antiretroviral therapy: A clinical perspective

Contemporary antiretroviral therapy (ART) regimens have high barriers to the development of drug resistance. However, resistance to earlier antiretrovirals and uncommon cases of resistance to contemporary ART illustrate the continued need for good clinical management of HIV drug resistance. Here, we describe HIV drug-resistance mechanisms, the interaction of HIV drug-resistant mutations and the patterns of drug resistance to contemporary ART. We then provide guidance on the management of HIV drug resistance, including how to limit the development of resistance and manage virologic failure that is complicated by resistance. To complement this, links to resources and treatment guidelines are provided that can assist with the interpretation of HIV drug resistance test results and optimal ART selection in the clinic.

Efavirenz: History, Development and Future

Efavirenz (Sustiva^®) is a first-generation non-nucleoside reverse transcriptase inhibitor (NNRTI) used to treat human immunodeficiency virus (HIV) type 1 infection or to prevent the spread of HIV. In 1998, the FDA authorized efavirenz for the treatment of HIV-1 infection. Patients formerly required three 200 mg efavirenz capsules daily, which was rapidly updated to a 600 mg tablet that only required one tablet per day. However, when given 600 mg once daily, plasma efavirenz concentrations were linked not only to poor HIV suppression but also to toxicity. Clinical data suggested that the standard dose of efavirenz could be reduced without compromising its effectiveness, resulting in a reduction in side effects and making the drug more affordable. Therefore, ENCORE1 was performed to compare the efficiency and safeness of a reduced dose of efavirenz (400 mg) with the standard dose (600 mg) plus two NRTI in antiretroviral-naïve HIV-infected individuals. Nowadays, due to the emergence of integrase strand transfer inhibitors (INSTIs), some consider that it is time to stop using efavirenz as a first-line treatment on a global scale, in the parts of the world where that is possible. Efavirenz has been a primary first-line antiviral drug for more than 15 years. However, at this moment, the best use for efavirenz could be for pre-exposure prophylaxis (PrEP) and repurposing in medicine.