1518. Prevalence of Integrase Inhibitor Resistance within an Urban Clinic Network After Adoption as First-line Therapy

Abstract

Abstract Background Limited data outside of randomized controlled trials exist reporting the prevalence of integrase inhibitor resistance (INSTI-R) since the approval and recommendation of INSTIs as first-line treatment for HIV. National surveillance data in 2018 estimated INSTI-R to be 6.3% in people with HIV (PWH) who had never achieved viral suppression, with 0.8% attributed to transmitted drug resistance (TDR). The purpose of this study was to describe the prevalence of INSTI-R in patients from a single urban clinic network on INSTI-containing regimens. Prevalence amongst University of Illinois Chicago Community Clinic Network (UCCN) patients on INSTI-containing single-tablet regimens specifically was previously reported. Methods This was a retrospective study of adult PWH followed at UCCN prescribed an INSTI-containing regimen between September 2017 and September 2020 with > two recorded HIV-1 RNA viral loads collected > 12 months apart. The primary endpoint was the difference in INSTI-R in UCCN patients compared to national data. Other outcomes included development of virologic failure (VF), defined as > 200 copies/mL in two consecutive HIV-1 RNA viral loads, and patient specific factors associated with VF. The primary endpoint was analyzed using a chi-square test. All other data are presented as descriptive statistics. Results Of 948 patients screened, 321 were included and followed an average of 30 months. Baseline characteristics are presented in Table 1. A total of 5 subjects had INSTI-R prior to switch resulting in a prevalence of 1.6%, which was significantly less than the national prevalence of 6.3% (p< 0.001). Of note, all patients with INSTI-R were previously treated with first generation INSTIs and none were deemed TDR. Study-defined VF occurred in 26 subjects (8.1%). Seven subjects (26.9%) were not taking antiretrovirals for > six weeks at the time of study-defined VF. Outcomes of patients with VF are outlined in Table 2. Subjects with a pre-treatment viral load > 100,000 were more likely to experience VF (p=0.0485). Conclusion Among UCCN patients on INSTI-containing regimens, INSTI-R rates were lower than the estimated national prevalence; however, this comparison is limited due to the large proportion of subjects with viral suppression at baseline. Disclosures All Authors: No reported disclosures