title: HIV Drug Resistance Profiles and Clinical Outcomes in Patients with Viremia Maintained at Very Low Levels.
abstract: We describe an observational study of clinical, virologic and drug resistance profiles in HIV-positive antiretroviral adherent subjects with stable low level viremia (LLV) 50-1,000 copies/mL for more than 12 months. Subjects were followed from time of first detectable viral load (VL). In total, 102 episodes of LLV were detected among 80 individuals. The median (mean, range) HIV copy number at genotyping was 250 (486, <50-3900) copies/mL after 14 (17.9, 0-58) months of LLV. Few patients maintained LLV for the entire 9 year period of observation, with half (52%) experiencing viremic progression following a stable period of LLV either spontaneously or after treatment interruption or failed regimen intensification. In the setting of prolonged periods of sustained LLV, mean duration 22 (range 8 - 106) months, drug resistance (DR) was almost universal. Resistance to ≥1 on-treatment drugs was defined in 97% of specimens and DR to all drugs in the treatment regimen in over half of all patients. Evolution of DR mutations during the period of LLV was observed in 20/28 (71%) subjects with specimens available for follow-up testing. This evolution was associated with viremic progression to levels >1000 copies/mL (p=0.03). Our data suggest that DR present in patients with LLV is likely to impact long term clinical outcomes, highlighting the importance of optimizing techniques to detect the presence of drug resistant HIV in the setting of LLV and the need for larger prospective studies to assess the emergence of DR in the setting of sustained LLV and the impact of this DR on treatment outcomes.
authors: Tufts University School of Medicine, Boston, MA, USA.
authors: Michael R
authors: MR
authors: Jordan
authors: Newton Wellesley Hospital, Newton, MA, USA.
authors: Julie
authors: J
authors: Winsett
authors: Largo Medical Center, Clearwater, FL, USA.
authors: Aileen
authors: A
authors: Tiro
authors: Tufts University School of Medicine, Boston, MA, USA.
authors: Vuth
authors: V
authors: Bau
authors: University of Massachusetts School of Medicine, Worcester, MA, USA.
authors: Rony S
authors: RS
authors: Berbara
authors: Beth Israel Deaconess Medical Center, Boston, MA, USA.
authors: Christopher
authors: C
authors: Rowley
authors: Beth Israel Deaconess Medical Center, Boston, MA, USA.
authors: Nobel
authors: N
authors: Bellosillo
authors: Tufts University School of Medicine, Boston, MA, USA.
authors: Christine
authors: C
authors: Wanke
authors: Monogram Biosciences South San Francisco, CA, USA.
authors: Eoin P
authors: EP
authors: Coakley
keywords: HIV; HIV drug resistance; low level viremia; treatment experienced patients