Comparison of Droplet Digital PCR versus qPCR Measurements on the International Scale for the Molecular Monitoring of Chronic Myeloid Leukemia Patients.

BACKGROUND: BCR-ABL1/ABL1 p210 measurement by quantitative polymerase chain reaction (qPCR) is used worldwide to monitor the molecular response in chronic myeloid leukemia (CML) patients. Droplet digital polymerase chain reaction (ddPCR) seems to show a greater sensitivity than qPCR, probably due to the high number of replicates analyzed in ddPCR for the comparison. Additionally, in a recently published comparison, ddPCR measurements were not adequately transformed into International Scale (IS). METHOD: We have analyzed 50 CML patients and ten non-CML donors in parallel by qPCR and ddPCR. To the best of our knowledge, this is the first study comparing both techniques under similar conditions, with BCR-ABL1/ABL1 measurements performed via both techniques transformed into IS. RESULTS: Qualitative and quantitative comparisons showed excellent results. The qualitative correlation showed a Kappa index of 0.94 (95% confidence interval [CI] 0.90-0.98) (P < 0.001). In the quantitative comparison, the absolute intra-class correlation coefficient was 0.868 (95% CI 0.734-0.937; P < 0.001), and Lin's concordance correlation coefficient was 0.863. The Passing-Bablock test indicated a slight proportional difference between qPCR and ddPCR. A quantitative and qualitative subanalysis including 40 patients with a molecular response of 3.0 or deeper showed similar results in every test. In addition, the proportional difference in the Passing-Bablock test disappeared. There were no differences in the sensitivity for BCR-ABL1 detection between qPCR and ddPCR (McNemar test, P = 0.5). CONCLUSIONS: In conclusion, our results show very good quantitative and qualitative correlations between BCR-ABL1/ABL1 p210 results obtained by qPCR and by ddPCR and confirm previous scarce data regarding the lack of an increase in sensitivity of ddPCR over qPCR in this setting.

Efficiency and effectiveness of the use of an acenocoumarol pharmacogenetic dosing algorithm versus usual care in patients with venous thromboembolic disease initiating oral anticoagulation: study protocol for a randomized controlled trial.

BACKGROUND: Hemorrhagic events are frequent in patients on treatment with antivitamin-K oral anticoagulants due to their narrow therapeutic margin. Studies performed with acenocoumarol have shown the relationship between demographic, clinical and genotypic variants and the response to these drugs. Once the influence of these genetic and clinical factors on the dose of acenocoumarol needed to maintain a stable international normalized ratio (INR) has been demonstrated, new strategies need to be developed to predict the appropriate doses of this drug. Several pharmacogenetic algorithms have been developed for warfarin, but only three have been developed for acenocoumarol. After the development of a pharmacogenetic algorithm, the obvious next step is to demonstrate its effectiveness and utility by means of a randomized controlled trial. The aim of this study is to evaluate the effectiveness and efficiency of an acenocoumarol dosing algorithm developed by our group which includes demographic, clinical and pharmacogenetic variables (VKORC1, CYP2C9, CYP4F2 and ApoE) in patients with venous thromboembolism (VTE). METHODS AND DESIGN: This is a multicenter, single blind, randomized controlled clinical trial. The protocol has been approved by La Paz University Hospital Research Ethics Committee and by the Spanish Drug Agency. Two hundred and forty patients with VTE in which oral anticoagulant therapy is indicated will be included. Randomization (case/control 1:1) will be stratified by center. Acenocoumarol dose in the control group will be scheduled and adjusted following common clinical practice; in the experimental arm dosing will be following an individualized algorithm developed and validated by our group. Patients will be followed for three months. The main endpoints are: 1) Percentage of patients with INR within the therapeutic range on day seven after initiation of oral anticoagulant therapy; 2) Time from the start of oral anticoagulant treatment to achievement of a stable INR within the therapeutic range; 3) Number of INR determinations within the therapeutic range in the first six weeks of treatment. DISCUSSION: To date, there are no clinical trials comparing pharmacogenetic acenocoumarol dosing algorithm versus routine clinical practice in VTE. Implementation of this pharmacogenetic algorithm in the clinical practice routine could reduce side effects and improve patient safety. TRIAL REGISTRATION: Eudra CT. Identifier: 2009-016643-18.