Novel Antivirals Targeting Lenacapavir-Resistant HIV

Abstract As of 2023, nearly 40 million people worldwide are living with human immunodeficiency virus (HIV), of which over three-fourths have access to antiretroviral therapies (ARTs). Although access to therapies improves an individual’s expected lifespan and quality of life, resistance-associated mutations (RAMs) can develop in the virus in response to treatment. As a result, novel antivirals are needed to expand upon current options that are available. Recently, the HIV capsid has become the newest FDA-approved antiviral target with the release of Gilead Sciences’ lenacapavir (LEN), as the capsid is essential in both early and late stages of the viral replication cycle. Unfortunately, administration of LEN – a picomolar-potency drug – has led to the early emergence of RAMs that severely deplete the drug’s potency. To overcome the burden of LEN-resistant RAMs, novel capsid effectors (CEs) have been developed by our laboratory in collaboration with a team of medicinal chemists. Three of these CEs target the highly reported LEN-resistant mutant CAM66I (over 80,000-fold resistance) with higher efficacy than LEN. I hypothesize that the unique structures of these novel CEs allow these compounds to work against LEN-resistant CAs, including CAQ67H, CAN74D, and CAQ67H/N74D, distinctly from LEN. First, biochemical and biophysical assessments of each CE•CA interaction will be done using biolayer interferometry, thermal shift assays, CA Tube assembly assays, and native mass spectrometry (Aim 1). Additionally, the in cellulo potency and cytotoxicity of each CE during infection with HIV – with and without these CA mutations – will be determined using cell-based antiviral assays (Aim 2). Finally, insight into the structural differences owing to the CEs’ activities will be provided by X-ray crystallography studies to solve high-resolution crystal structures of each CE•CA complex (Aim 3). For all assays, comparisons will be made between WT and mutant CAs and between these CEs and LEN to understand mechanistic differences among each CE•CA combination. Together, these three aims will detail insight into methods of circumventing LEN resistance that can be used to optimize novel CEs with potential to be used as ARTs. As a result, these studies will allow us to continue combatting drug-resistant HIV through structure-based drug design, with the goal of suppressing the HIV epidemic.