The benefit of quality control charts (QCC) for routine quantitative BCR-ABL1 monitoring in chronic myeloid leukemia.

Quantitative real-time polymerase chain reaction (qRT-PCR) is state of the art in molecular monitoring of minimal residual disease in chronic myeloid leukemia (CML). In this context, maintenance of assay fidelity and detection of technical inaccuracy are crucial. Beside multiple common negative controls for the clinical sample preparations, quality control charts (QCC) are a common validation tool to sustain high process quality by continuously recording of qRT-PCR control parameters. Here, we report on establishment and benefit of QCC in qRT-PCR-based CML diagnostics. The absolute quantification of BCR-ABL1 fusion transcripts in patient samples is based on coamplification of a serially diluted reference plasmid (pME-2). For QCC establishment the measured Ct values of each pME-2 standard dilution (4-400,000) of a test set resembling 21 sequential qRT-PCR experiments were recorded and statistically evaluated. Test set data were used for determination of warning limits (mean +/- 2-fold standard deviation) and control (intervention) limits (mean +/- 3-fold standard deviation) to allow rapid detection of defined out-of-control situations which may require intervention. We have retrospectively analyzed QCC data of 282 sequential qRT-PCR experiments (564 reactions). Data evaluation using QCCs revealed three out-of-control situations that required intervention like experiment repeats, renewal of pME-2 standards, replacement of reagents or personnel re-training. In conclusion, with minimal more effort and hands-on time QCC rank among the best tools to grant high quality and reproducibility in CML routine molecular diagnosis

Diagnostic performance of the molecular BCR-ABL1 monitoring system may impact on inclusion of CML patients in stopping trials.

In chronic myeloid leukemia (CML), the duration of deep molecular response (MR) before treatment cessation (MR4 or deeper, corresponding to BCR-ABL1 ≤ 0.01% on the International Scale (IS)) is considered as a prognostic factor for treatment free remission in stopping trials. MR level determination is dependent on the sensitivity of the monitoring technique. Here, we compared a newly established TaqMan (TM) and our so far routinely used LightCycler (LC) quantitative reverse transcription (qRT)-PCR systems for their ability to achieve the best possible sensitivity in BCR-ABL1 monitoring. We have comparatively analyzed RNA samples from peripheral blood mononuclear cells of 92 randomly chosen patients with CML resembling major molecular remission (MMR) or better and of 128 CML patients after treatment cessation (EURO-SKI stopping trial). While our LC system utilized ABL1, the TM system is based on GUSB as reference gene. We observed 99% concordance with respect to achievement of MMR. However, we found that 34 of the 92 patients monitored by TM/GUSB were re-classified to the next inferior MR log level, especially when LC/ABL1-based results were borderline to thresholds. Thirteen patients BCR-ABL1 negative in LC/ABL1 became positive after TM/GUSB analysis. In the 128 patients included in the EURO-SKI trial identical molecular findings were achieved for 114 patients. However, 14 patients were re-classified to the next inferior log-level by the TM/GUSB combination. Eight of these patients relapsed after treatment cessation; two of them were re-classified from MR4 to MMR and therefore did not meet inclusion criteria anymore. In conclusion, we consider both methods as comparable and interchangeable in terms of achievement of MMR and of longitudinal evaluation of clinical courses. However, in LC/ABL1 negative samples, slightly enhanced TM/GUSB sensitivity may lead to inferior classification of clinical samples in the context of TFR

Which health-related quality of life aspects are important to patients with chronic myeloid leukemia receiving targeted therapies and to health care professionals? : GIMEMA and EORTC Quality of Life Group

The objective of this study was to investigate the health-related quality of life (HRQOL) aspects valued the most by patients with chronic myeloid leukemia (CML) receiving targeted therapies (TT), and to compare their perception with that of health-care professionals' (HCPs). Semi-structured interviews were conducted with 137 CML patients receiving TT from five different countries. An additional sample of 99 CML patients, completing an online interview, was considered for supportive analyses. A sample of 59 HCPs from 12 countries also participated in the study. Patients and HCPs were asked to rate and rank the importance of a predefined list of 74 HRQOL aspects of potential relevance for CML patients. Patients and HCPs agreed that the following five aspects are most important: fatigue, muscle cramps, swelling, worries, and uncertainty about health condition in the future, and importance of social support in coping with the disease. However, the difference in rankings between the two groups was substantial with respect to other HRQOL aspects investigated. Patients valued some issues related to symptoms much higher than HCPs, thus suggesting that a better symptom management could be the crucial aspects to improve HRQOL of CML patient

The benefit of quality control charts (QCC) for routine quantitative <i>BCR-ABL1</i> monitoring in chronic myeloid leukemia - Fig 2

<p><b>Visualization of decay in the life span of five consecutive working solutions (A-E) of the pME-2 standard dilution 4000.</b> The Ct drift due to molecule degradation is shown by the increasing Ct values and is visualizes by the linear regression lines (red). For noise reduction and a more compact image size data point calculations were based on the mean of duplex PCR reactions.</p

Decay of plasmid working solutions.

<p>Decay of plasmid working solutions.</p

Inter-experimental variance for the seven pME-2 standard dilutions.

<p>Calculated were performed from 387 consecutive PCR experiments. Numbers on the x-axis correspond to the amounts of pME-2 plasmid molecules that serve as target within the respective PCR reactions. Decreasing numbers of target molecules inversely correlate with standard error of mean (SEM given in Ct values) due to pipetting inaccuracy.</p