Shagufta Aslam

An International Multicenter Performance Analysis of Cytomegalovirus Load Tests

A new quantitative polymerase chain reaction assay, COBAS AmpliPrep/COBAS TaqMan CMV Test, was developed using the first World Health Organization cytomegalovirus standard. It demonstrated a high level of interlaboratory agreement and precision compared to quantitative results obtained with tests used by 5 different laboratories.

An International Multicenter Performance Analysis of CMV Viral Load Tests

A new quantitative polymerase chain reaction assay, COBAS AmpliPrep/COBAS TaqMan CMV Test, was developed using the first World Health Organization cytomegalovirus standard. It demonstrated a high level of interlaboratory agreement and precision compared to quantitative results obtained with tests used by 5 different laboratories.

Detection of low HCV viraemia by repeated HCV RNA testing predicts treatment failure to triple therapy with telaprevir

Early on‐treatment virological response is one of the most important predictors for sustained virological response (SVR) to treatment of chronic hepatitis C virus (HCV) genotype 1 infection with triple therapy including HCV protease inhibitors (PI). Treatment duration (24 vs. 48 weeks) is based on HCV RNA results at weeks 4 and 12 of PI therapy when HCV RNA must be ‘undetectable’ to allow shorter therapy.

CMV antigenemia and quantitative viral load assessments in hematopoietic stem cell transplant recipients

BACKGROUND Sensitive and reliable diagnostic tests are essential for the prevention of cytomegalovirus (CMV) disease after hematopoietic stem cell transplantation (HSCT). pp65 antigenemia and polymerase chain reaction (PCR) assays are commonly used to monitor CMV in HSCT recipients. However, there is considerable intra- and inter-laboratory variability in the results, which impact comparability and clinical practice. OBJECTIVES/STUDY DESIGN Using 380 samples from 135 HSCT recipients, we compared the new FDA approved quantitative PCR assay, COBAS(®) AmpliPrep/COBAS(®) TaqMan(®) CMV test (CAP/CTM CMV test) developed and standardized using the 1st WHO International Standard for CMV with pp65 antigenemia and COBAS(®) AMPLICOR MONITOR CMV tests. RESULTS The median time between transplantation and testing samples was 57 days (range, 0-207 days). The median CMV load (log(10)) was 3.17 IU/mL (3.21 copies/mL). Among samples with detectable CMV load, 52% were negative by pp65 antigenemia. CMV loads were higher in pp65 antigenemia-positive than in negative samples. One pp65-antigenemia-positive cell per 100,000 leukocytes corresponded to a median CMV load of 1200 IU/mL. CMV loads determined by the CAP/CTM CMV test were slightly lower than the ones by the AMPLICOR MONITOR CMV test (-0.15 [95% CI, -0.18 to -0.13] copies/mL), but slope differences indicated only limited co-linearity. CONCLUSIONS The CAP/CTM CMV test is more sensitive than pp65 antigenemia and the AMPLICOR MONITOR CMV test in HSCT recipients. The lower limit of quantification and co-linearity with the international WHO standard renders the CAP/CTM CMV test suitable for future clinical trials defining viral load thresholds of CMV therapy.

Evaluation of the COBAS(®) AmpliPrep/COBAS(®) TaqMan(®) HCV Test, v2.0 and comparison to assays used in routine clinical practice in an international multicenter clinical trial: The ExPECT study.

BACKGROUND The COBAS(®) AmpliPrep(®)/COBAS(®) TaqMan(®) HCV Test, v2.0 (CAP/CTM2) is used for HCV RNA viral load monitoring. OBJECTIVES The performance of the CAP/CTM2 was compared to other widely used tests, including a manual version of the assay (the COBAS(®) TaqMan(®) HCV Test, v2.0 for use with the High Pure System, HPS/CTM2) predominantly used during phase III clinical trials for the new direct acting antiviral therapies. STUDY DESIGN Low HCV RNA level comparisons were performed across tests (Abbott Realtime HCV Test, ART; COBAS(®) AmpliPrep(®)/COBAS(®) TaqMan(®) HCV Test, v1.0, CAP/CTM1; CAP/CTM2; and HPS/CTM2) using dilutions of the 2nd HCV WHO International Standard. Additionally, the clinical performance of the CAP/CTM2 was evaluated with 421 leftover HCV RNA-positive routine clinical samples. RESULTS All quantifiable WHO dilutions were within ±0.3log10IU/mL of the expected results across tests and the analytical sensitivity resulted in a limit of detection of 12IU/mL (95% confidence interval, 10, 15). When clinical samples were tested the results for 87% (367 of 421) of all sample comparisons were within ±0.5log10IU/mL. When low viral load results (25-3500IU/mL) were compared, values obtained by the ART assay were significantly lower (p<0.0001) than those obtained with the CAP/CTM2. CONCLUSIONS The new CAP/CTM2 showed good accuracy with comparable sensitivity to comparator assays. The new kit is well-suited for use in the routine diagnostic laboratory, especially for accurate monitoring of patients receiving triple therapy or interferone-free regimens.

HCV RNA detection in HCV antibody-positive patients with the COBAS AmpliPrep/COBAS TaqMan HCV test, v2.0 in comparison with FDA-approved nucleic acid tests.

BACKGROUND Analysis of hepatitis C virus (HCV) RNA levels is critical for assessing the efficacy of antiviral therapy and the achievement of a sustained virologic response. OBJECTIVE AND STUDY DESIGN This study evaluated the clinical performance of the COBAS AmpliPrep/COBAS TaqMan HCV quantitative test, version 2.0 (TAQMAN v2.0) with the COBAS AmpliPrep/COBAS TaqMan HCV quantitative test, version 1.0 (TAQMAN v1.0), the VERSANT HCV qualitative assay (VERSANT), and the COBAS AMPLICOR HCV test, v2.0 (AMPLICOR) qualitative test for the detection of HCV RNA in serum or EDTA plasma from patients who are or have been infected with HCV and carry HCV antibodies. RESULTS A total of 277 participants were evaluable for the percent agreement analysis of the TAQMAN v2.0 with the VERSANT and with the AMPLICOR. The overall percent agreement between the TAQMAN v2.0 and the VERSANT or the AMPLICOR was 99.3% (95% CI: 97.4%, 99.8%) or 98.9% (95% CI: 96.9%, 99.6%), respectively. The overall percent agreement between the TAQMAN v2.0 and the TAQMAN v1.0 when 267 of the original samples were assessed was 98.9% (95% CI=96.7%, 99.6%). CONCLUSION The TAQMAN v2.0 demonstrated high correlation with the previously approved HCV RNA quantitative and qualitative tests.

Performance of the cobas HPV Test for the Triage of Atypical Squamous Cells of Undetermined Significance Cytology in Cervical Specimens Collected in SurePath

Objectives Determine performance of the cobas human papillomavirus (HPV) test for triage of atypical squamous cells of undetermined significance (ASC-US) in SurePath. Methods Women presenting for routine screening had cervical specimens collected in SurePath and specimen transport medium (STM); those with ASC-US cytology underwent colposcopy. Performance of cobas HPV in SurePath specimens that had undergone a preanalytic procedure to reverse possible cross-linking of HPV DNA was compared with Hybrid Capture 2 (hc2) specimens in STM. Results Among 856 women, HPV prevalence was 45.8%; HPV 16 and HPV 18 prevalences were lower than expected in the 21- to 29-year-old group in this highly vaccinated population. cobas HPV performance in SurePath was comparable to hc2 in STM. Sensitivity and specificity for detection of cervical intraepithelial neoplasia grade 3 or worse were 87.5% (95% confidence interval [CI], 71.9%-95.2%) and 55.5% (95% CI, 52.1%-58.9%) for cobas and 85.3% (95% CI, 69.9%-93.6%) and 54.7% (95% CI, 51.4%-57.9%) for hc2. Sensitivity was negatively affected by random biopsies performed at colposcopy; comparable sensitivities were achieved in the nonvaccinated and vaccinated populations with disease determined by directed biopsy only. Conclusions Performance of cobas HPV for ASC-US triage in pretreated SurePath specimens meets criteria for validation. Preliminary data indicate reliable performance of HPV testing in a highly vaccinated population.

Cervical Precancer and Cancer Risk by Human Papillomavirus Status and Cytologic Interpretation: Implications for Risk-Based Management

Background: Cervical cancer risks, estimated by using cervical intraepithelial neoplasia grade 3 (CIN3) or more severe diagnoses (≥CIN3) endpoints, have not been quantified for different combinations of results from currently approved screening methods. Understanding these risks will guide optimal patient management. Methods: Women aged ≥25 years (n = 7,823) underwent high-risk human papillomavirus (hrHPV) and liquid-based cytology (LBC) testing. Women with hrHPV-positive results and/or abnormal LBC, plus a random subset of hrHPV and LBC negatives, underwent colposcopy; those without ≥CIN2 at baseline were screened annually by LBC and referred to colposcopy for an abnormal LBC (n = 7,392). One- and 3-year ≥CIN3 risks with 95% confidence intervals (95% CI) were calculated for paired hrHPV and LBC (hrHPV/LBC) results. Results: One-year ≥CIN3 risks ranged from 81.27% (95% CI, 66.02%–90.65%) for HPV16 positive/high-grade to 0.33% (95% CI, 0.18%–0.62%) for hrHPV negative/negative for intraepithelial lesion or malignancy (NILM). One-year ≥CIN3 risk for HPV16/NILM (13.95%; 95% CI, 10.98%–17.58%) was greater than low-grade squamous intraepithelial lesion (LSIL; 7.90%; 95% CI, 5.99%–10.37%; P = 0.002) and similar to hrHPV-positive/LSIL (11.45%; 95% CI, 8.61%–15.07%; P = 0.3). Three-year ≥CIN3 risks for HPV16 positive/LSIL and HPV16/atypical squamous cells of undetermined significance was 24.79% (95% CI, 16.44%–35.58%) and 24.36% (95% CI, 15.86%–35.50%), respectively, and 0.72% (95% CI, 0.45%–1.14%) for hrHPV negative/NILM. Conclusions: hrHPV and LBC results stratify cervical cancer risk by more than two orders of magnitude. HPV16-positive women, regardless of the LBC result, warrant immediate colposcopy. Women with concurrent HPV16 and high-grade LBC might consider treatment without a confirmatory biopsy with informed decision-making with their provider. Impact: These results provide relevant benchmarks for risk-based cervical cancer screening and management. Cancer Epidemiol Biomarkers Prev; 25(12); 1595–9. ©2016 AACR.