Impact of HIV-1 Integrase L74F and V75I Mutations in a Clinical Isolate on Resistance to Second-Generation Integrase Strand Transfer Inhibitors

Abstract

A novel HIV-1 integrase mutation pattern, L74F V75I, which conferred resistance to first-generation integrase strand transfer inhibitors (INSTIs), was identified in a clinical case with virological failure under a raltegravir-based regimen. Addition of L74F V75I to N155H or G140S Q148H increased resistance levels to the second-generation INSTIs dolutegravir (Ͼ385-and 100-fold, respectively) and cabotegravir (153-and 197-fold, respectively). These findings are important for the development of an accurate system for interpretation of INSTI resistance and the rational design of next-generation INSTIs.KEYWORDS dolutegravir, drug resistance mechanisms, human immunodeficiency virus, integrase, integrase strand transfer inhibitor I ntegrase strand transfer inhibitors (INSTIs) constitute the latest class of available antiretroviral agents exhibiting potent antiretroviral effects in vitro and vivo (1-8). The first-generation INSTIs raltegravir (RAL) and elvitegravir (EVG) display broad crossresistance, whereas second-generation INSTIs of carbamoyl pyridine analogues, dolutegravir (DTG) and cabotegravir (CAB), demonstrate superior activity against firstgeneration INSTI-resistant HIV-1 variants (4, 9-13). Although a DTG resistance mutation, R263K, has been reported, and its resistance mechanism has been well studied (10,12,14,15), other potential DTG resistance mutations and their mechanisms are not fully understood.In a clinical case (Fig. 1A), the plasma HIV-1 RNA level rebounded to 2,900 copies/ml 1 year after starting antiretroviral therapy (ART) that included tenofovir disoproxil fumarate (TDF), emtricitabine (FTC), and RAL. However, no known INSTI resistance mutations were identified based on major drug resistance mutation lists (IAS-USA drug resistance mutations list [16] and the HIV Drug Resistance Database at Stanford University [HIVDB]) at time points 2 and 3 (Fig. 1B). Clinical samples were obtained from the fresh plasma of a patient attending the outpatient clinic of the National Hospital Organization Nagoya Medical Center. The Institutional Review Board approved this study , and written informed consent was obtained from this patient. To identify novel mutations associated with RAL resistance in the clinical isolates, we constructed infectious HIV-1 clones with cDNA fragments of the integrase (IN)-coding region derived from the clinical isolates and performed phenotypic resistance assays using TZM-bl cells as previously described (8, 17). Briefly, viral RNA was extracted from

Antiviral Activity of Bictegravir and Cabotegravir against Integrase Inhibitor-Resistant SIVmac239 and HIV-1

“…The clinical relevance of such differences remains unexplored. In this case, results obtained using CBMCs were in agreement with previous reports and show that N155H remain susceptible to CAB inhibition (20,46). In addition, levels of resistance conferred by N155H in single cycle assays were not statistically significant for either HIV-1 or SIVmac239 (Fig.…”

Comparison of the Antiviral Activity of Bictegravir against HIV-1 and HIV-2 Isolates and Integrase Inhibitor-Resistant HIV-2 Mutants

“…We previously showed that the results obtained with this assay are concordant with those seen in spreading infections of immortalized T-cell lines, as demonstrated for the INIs raltegravir (17), dolutegravir (21), and cabotegravir (22). In addition, other groups have used similar single-cycle assays to quantify the activity of various INIs against HIV-1 and simian immunodeficiency virus (SIV) (33,(36)(37)(38)(39)(40).…”

Structural Implications of Genotypic Variations in HIV-1 Integrase From Diverse Subtypes

“…Both T97 and F121 are known INSTI DRM positions ( Wensing et al, 2017 ). In addition, a recent report showed that the L74F mutation increased resistance to second-generation INSTIs ( Hachiya et al, 2017 ). Hence, the impact of PMs in this hydrophobic cluster appears rather complex.…”