HIV-1 Integrase T218I/S Polymorphisms Do Not Reduce HIV-1 Integrase Inhibitors' Phenotypic Susceptibility

The recently Food and Drug Administration (FDA)-approved cabotegravir (CAB) has demonstrated efficacy as an antiretroviral agent for HIV treatment and prevention, becoming an important tool to stop the epidemic in the United States of America (USA). However, the effectiveness of CAB can be compromised by the presence of specific integrase natural polymorphisms, including T97A, L74M, M50I, S119P, and E157Q, particularly when coupled with the primary drug-resistance mutations G140S and Q148H. CAB's recent approval as a pre-exposure prophylaxis (PrEP) may increase the number of individuals taking CAB, which, at the same time, could increase the number of epidemiological implications. In this context, where resistance mutations, natural polymorphisms, and the lack of drug-susceptibility studies prevail, it becomes imperative to comprehensively investigate concerns related to the use of CAB. We used molecular and cell-based assays to assess the impact of T218I and T218S in the context of major resistance mutations G140S/Q148H on infectivity, integration, and resistance to CAB. Our findings revealed that T218I and T218S, either individually or in combination with G140S/Q148H, did not significantly affect infectivity, integration, or resistance to CAB. Notably, these polymorphisms also exhibited neutrality concerning other widely used integrase inhibitors, namely raltegravir, elvitegravir, and dolutegravir. Thus, our study suggests that the T218I and T218S natural polymorphisms are unlikely to undermine the effectiveness of CAB as a treatment and PrEP strategy.