Prevalence of key resistance mutations K65R, K103N, and M184V as minority HIV-1 variants in chronically HIV-1 infected, treatment-naïve patients.

BACKGROUND AND OBJECTIVES: Minority drug-resistant HIV-1 variants, undetected by conventional genotyping, may impair the outcome of antiretroviral therapy (ART). Thus, we retrospectively analyzed the prevalence of minority drug-resistant HIV-1 variants before ART in chronically HIV-1 infected patients initiating first-line therapy and assessed the impact on clinical outcome in the prospective German Truvada cohort. STUDY
DESIGN: Samples from 146 antiretroviral treatment-naïve patients were collected between April 2005 and August 2006. K65R, K103N, and M184V variants at low frequencies were detected by allele-specific real-time PCR.
RESULTS: Minority drug-resistant HIV-1 variants were detected in 20/146 patients (13.7%): the M184V mutation in 12/146 patients (8.2%), the K103N mutation in 8/146 patients (5.5%), and the K65R mutation in 4/146 patients (2.7%). Four patients with the M184V mutation also harbored the K65R or the K103N mutation. The 12- and 24 months virological efficacy data revealed that the rate of treatment failure was not increased in the group of patients harboring minority drug-resistant HIV-1 variants prior to ART.
CONCLUSIONS: Minority drug-resistant HIV-1 variants can be frequently detected in treatment-naïve, chronically HIV-1 infected patients. Despite the presence of those mutations as minority variants before initiating ART, most of the patients were successfully treated.