Treatment Failure in HIV-Infected Children on Second-line Protease Inhibitor-Based Antiretroviral Therapy.

BACKGROUND: Human immunodeficiency virus (HIV)-infected children failing second-line antiretroviral therapy (ART) have no access to third-line antiretroviral drugs in many resource-limited settings. It is important to identify risk factors for second-line regimen failure. METHODS: HIV-infected children initiating protease inhibitor (PI)-containing second-line ART within the Program for HIV Prevention and Treatment observational cohort study in Thailand between 2002 and 2010 were included. Treatment failure was defined as confirmed HIV type 1 RNA load >400 copies/mL after at least 6 months on second-line regimen or death. Adherence was assessed by drug plasma levels and patient self-report. Cox proportional hazards regression analyses were used to identify risk factors for failure. RESULTS: A total of 111 children started a PI-based second-line regimen, including 59 girls (53%). Median first-line ART duration was 1.9 years (interquartile range [IQR], 1.4-3.3 years), and median age at second-line initiation was 10.7 years (IQR, 6.3-13.4 years). Fifty-four children (49%) experienced virologic failure, and 2 (2%) died. The risk of treatment failure 24 months after second-line initiation was 41%. In multivariate analyses, failure was independently associated with exposure to first-line ART for >2 years (adjusted hazard ratio [aHR], 1.8; P = .03), age >13 years (aHR, 2.9; P < .001), body mass index-for-age z score < -2 standard deviations at second-line initiation (aHR, 2.8; P = .03), and undetectable drug levels within 6 months following second-line initiation (aHR, 4.5; P < .001). CONCLUSIONS: Children with longer exposure to first-line ART, entry to adolescence, underweight, and/or undetectable drug levels were at higher risk of failing second-line ART and thus should be closely monitored.

OLA-Simple: A software-guided HIV-1 drug resistance test for low-resource laboratories.

BACKGROUND: HIV drug resistance (HIVDR) testing can assist clinicians in selecting treatments. However, high complexity and cost of genotyping assays limit routine testing in settings where HIVDR prevalence has reached high levels. METHODS: The oligonucleotide ligation assay (OLA)-Simple kit was developed for detection of HIVDR against first-line non-nucleoside/nucleoside reverse transcriptase inhibitors and validated on 672 codons (168 specimens) from subtypes A, B, C, D, and AE. The kit uses dry reagents to facilitate assay setup, lateral flow devices for visual HIVDR detections, and in-house software with an interface for guiding users and analyzing results. FINDINGS: HIVDR analysis of specimens by OLA-Simple compared to Sanger sequencing revealed 99.6 ±â€¯0.3% specificity and 98.2 ±â€¯0.9% sensitivity, and compared to high-sensitivity assays, 99.6 ±â€¯0.6% specificity and 86.2 ±â€¯2.5% sensitivity, with 2.6 ±â€¯0.9% indeterminate results. OLA-Simple was performed more rapidly compared to Sanger sequencing (<4 h vs. 35-72 h). Forty-one untrained volunteers blindly tested two specimens each with 96.8 ±â€¯0.8% accuracy. INTERPRETATION: OLA-Simple compares favorably with HIVDR genotyping by Sanger and sensitive comparators. Instructional software enabled inexperienced, first-time users to perform the assay with high accuracy. The reduced complexity, cost, and training requirements of OLA-Simple could improve access to HIVDR testing in low-resource settings and potentially allow same-day selection of appropriate antiretroviral therapy. FUND: USA National Institutes of Health R01; the Clinical and Retrovirology Research Core and the Molecular Profiling and Computational Biology Core of the UW CFAR; Seattle Children's Research Institute; UW Holloman Innovation Challenge Award; Pilcher Faculty Fellowship.

Development and validation of an oligonucleotide ligation assay to detect lamivudine resistance in hepatitis B virus.

Treatment of chronic hepatitis B virus (HBV) infection with lamivudine-monotherapy rapidly selects mutant variants in a high proportion of individuals. Monitoring lamivudine resistance by consensus sequencing is costly and insensitive for detection of minority variants. An oligonucleotide ligation assay (OLA) for HBV lamivudine-resistance was developed and compared to consensus sequencing. Both assays detected drug resistance mutations in 35/64 (54.7%) specimens evaluated, and OLA detected minority mutants in an additional six (9.4%). OLA may offer a sensitive and inexpensive alternative to consensus sequencing for detection of HBV drug resistance in resource-limited settings.