scholarly journals Assessment of individual molecular response in chronic myeloid leukemia patients with atypical BCR-ABL1 fusion transcripts: recommendations by the EUTOS cooperative network

2021 ◽  
Author(s):  
Vivien Schäfer ◽  
Helen E. White ◽  
Gareth Gerrard ◽  
Susanne Möbius ◽  
Susanne Saussele ◽  
...  
Keyword(s):  
Chronic Myeloid Leukemia ◽  
Myeloid Leukemia ◽  
Residual Disease ◽  
False Negative ◽  
Patient Specific ◽  
Molecular Response ◽  
Real Time Quantitative Pcr ◽  
Log Reduction ◽  
Negative Results ◽  
False Negative Results

Abstract Purpose Approximately 1–2% of chronic myeloid leukemia (CML) patients harbor atypical BCR-ABL1 transcripts that cannot be monitored by real-time quantitative PCR (RT-qPCR) using standard methodologies. Within the European Treatment and Outcome Study (EUTOS) for CML we established and validated robust RT-qPCR methods for these patients. Methods BCR-ABL1 transcripts were amplified and sequenced to characterize the underlying fusion. Residual disease monitoring was carried out by RT-qPCR with specific primers and probes using serial dilutions of appropriate BCR-ABL1 and GUSB plasmid DNA calibrators. Results were expressed as log reduction of the BCR-ABL1/GUSB ratio relative to the patient-specific baseline value and evaluated as an individual molecular response (IMR). Results In total, 330 blood samples (2–34 per patient, median 8) from 33 CML patients (19 male, median age 62 years) were analyzed. Patients expressed seven different atypical BCR-ABL1 transcripts (e1a2, n = 6; e6a2, n = 1; e8a2, n = 2; e13a3, n = 4; e14a3, n = 6; e13a3/e14a3, n = 2; e19a2, n = 12). Most patients (61%) responded well to TKI therapy and achieved an IMR of at least one log reduction 3 months after diagnosis. Four patients relapsed with a significant increase of BCR-ABL1/GUSB ratios. Conclusions Characterization of atypical BCR-ABL1 transcripts is essential for adequate patient monitoring and to avoid false-negative results. The results cannot be expressed on the International Scale (IS) and thus the common molecular milestones and guidelines for treatment are difficult to apply. We, therefore, suggest reporting IMR levels in these cases as a time-dependent log reduction of BCR-ABL1 transcript levels compared to baseline prior to therapy.

In search of the original leukemic clone in chronic myeloid leukemia patients in complete molecular remission after stem cell transplantation or imatinib

Blood ◽  
2010 ◽  
Vol 116 (8) ◽  
pp. 1329-1335 ◽  
Author(s):  
Manuel Sobrinho-Simões ◽  
Vicki Wilczek ◽  
Joannah Score ◽  
Nicholas C. P. Cross ◽  
Jane F. Apperley ◽  
...  
Keyword(s):  
Stem Cell ◽  
Chronic Myeloid Leukemia ◽  
Stem Cell Transplantation ◽  
Cell Transplantation ◽  
Myeloid Leukemia ◽  
Residual Disease ◽  
Quantitative Polymerase Chain Reaction ◽  
Patient Specific ◽  
Molecular Response ◽  
Leukemic Clone

Abstract It is not clear if absence of BCR-ABL transcripts—complete molecular response (CMR)—is synonymous with, or required for, cure of chronic myeloid leukemia (CML). Some patients achieve CMR with imatinib (IM), but most relapse shortly after treatment discontinuation. Furthermore, most patients in long-term remission (LTR) post–stem cell transplantation (SCT) are considered functionally cured, although some remain occasionally positive for low-level BCR-ABL mRNA. Interpretation of the latter is complicated because it has been observed in healthy subjects. We designed a patient-specific, highly sensitive, DNA quantitative polymerase chain reaction to test follow-up samples for the original leukemic clone, identified by its unique genomic BCR-ABL fusion (gBCR-ABL). In 5 IM-treated patients in CMR, gBCR-ABL was detected in transcript-negative samples; 4 patients became gBCR-ABL-negative with continuing IM therapy. In contrast, of 9 patients in LTR (13-27 years) post-SCT, gBCR-ABL was detected in only 1, despite occasional transcript-positive samples in 8 of them. In conclusion, in IM-treated patients, absence of transcripts should not be interpreted as absence of the leukemic clone, although continuing IM after achievement of CMR may lead to further reduction of residual disease. Post-SCT, we found little evidence that the transcripts occasionally detected originate from the leukemic clone.

scholarly journals Comparison of an international scale method and a log reduction method for monitoring of early molecular response in chronic myeloid leukemia patients

2016 ◽  
Vol 51 (1) ◽  
pp. 58 ◽  
Author(s):  
Sunhyun Ahn ◽  
Young Ae Lim ◽  
Wee Gyo Lee ◽  
Seong Hyun Jeong ◽  
Joon Seong Park ◽  
...  
Keyword(s):  
Chronic Myeloid Leukemia ◽  
Myeloid Leukemia ◽  
Reduction Method ◽  
Molecular Response ◽  
Log Reduction ◽  
Scale Method ◽  
International Scale

Molecular Monitoring and Mutations in Chronic Myeloid Leukemia: How to Get the Most out of Your Tyrosine Kinase Inhibitor

2014 ◽  
pp. 167-175 ◽  
Author(s):  
Michele Baccarani ◽  
Simona Soverini ◽  
Caterina De Benedittis
Keyword(s):  
Chronic Myeloid Leukemia ◽  
Tyrosine Kinase ◽  
Myeloid Leukemia ◽  
Sanger Sequencing ◽  
Mutational Analysis ◽  
Residual Disease ◽  
Kinase Domain ◽  
Response To Treatment ◽  
Molecular Response ◽  
Therapeutic Decisions

The course of chronic myeloid leukemia (CML) and the response to treatment with tyrosine kinase inhibitors (TKIs) are best monitored and assessed using two molecular tests: the first is real-time quantitative reverse transcription-polymerase chain reaction (RQ-PCR), which measures the size of residual disease that is expressed as BCR-ABL1% (the ratio between BCR-ABL1 and a control gene) and the other is mutational analysis by Sanger sequencing, which checks for the presence of BCR-ABL1 kinase domain point mutations. Both tests are technically demanding and require a high level of specialization and standardization. RQ-PCR, when performed on a regular basis, allows for the defining of molecular response (MR) levels as log reduction from a standardized baseline: major molecular response (MMR or MR3) that is the best predictor of survival; and the deeper molecular response (MR4, MR4.5, and MR5) that is necessary to enroll a patient in a trial aiming at treatment-free remission (TFR). Mutational analysis, to be performed in case of failure or warning by Sanger sequencing, allows for screening of the BCR-ABL1 kinase domain for mutations conferring resistance to TKIs. Since different mutations have different degrees of sensitivity to each of the currently available TKI, the knowledge of BCR-ABL1 kinase domain–mutation status is necessary for subsequent treatment choice. Optimal patient management requires that MR and mutational information be rationally interpreted at both the technical and at the biologic level, and put into context—therapeutic decisions also take into account other factors, such as age, comorbidities, side effects, compliance, and treatment-related complications.

Imatinib Mesylate Therapy in Late Ph+ Chronic Myeloid Leukemia Patients in Stable Complete Cytogenetic Response after Interferon-Alpha Results in a Very High Complete Molecular Response Rate.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 2158-2158
Author(s):  
Giuliana Alimena ◽  
Massimo Breccia ◽  
Luigia Luciano ◽  
Fabrizio Quarantelli ◽  
Daniela Diverio ◽  
...  
Keyword(s):  
Chronic Myeloid Leukemia ◽  
Imatinib Mesylate ◽  
Copy Number ◽  
Myeloid Leukemia ◽  
Residual Disease ◽  
Cytogenetic Response ◽  
Molecular Response ◽  
Complete Cytogenetic Response ◽  
Complete Molecular Response

Abstract Imatinib mesylate was given to 26 Philadelphia positive (Ph+) chronic myeloid leukemia (CML) patients who were in late chronic phase (CP) and in stable complete cytogenetic response (CCR) after interferon-alfa (IFN-α), but showed persistent positive residual disease at PCR analysis under this treatment. At diagnosis median age was 40 years (range 21–64) and according to Sokal’s score, 18 patients were low risk and 8 were intermediate risk. Median IFN treatment was 88 mo.s (range 15–202) and median CCR duration was 73 mo.s (range 10–148). Imatinib was administered at the standard dose of 400 mg/die, after stopping IFN for 1 week. Residual disease was measured on bone marrow (BM) cells at baseline, before starting Imatinib, at 3, 6, 12, 18 mo.s and at the last follow-up (median 32 mo.s, range 21–49), by assaying BCR-ABL transcripts using quantitative PCR (RQ-PCR). The copy number (CN) of BCR/ABL and ABL transcript were derived by the interpolation of CT values to the appropriate standard curve, and the result, for each sample, was expressed as ratio of BCR/ABL mRNA copies to ABL mRNA x 100 (normalized copy number - NCN). Imatinib treatment resulted in a progressive and consistent decline of residual disease in all but one patient, from a median of 0.89 at baseline to 0.01 at the end of follow-up. Major molecular response (BCR/ABL levels <0.1) was reached in 20 patients (77%) and BCR/ABL transcripts were undetectable in 13 (50%). Achievement of molecular response was significantly correlated with post-IFN baseline transcript level (mean 1.194 for patients achieving complete molecular response vs 18,97 for those who did not; p<0.001), but not with other clinical/biological patient characteristics. In all patients, imatinib was well tolerated with no side effects requiring drug dose reduction or dose discontinuation. Albeit obtained from an unusual subset of selected patients with favourable prognosis, and likely particularly sensitive to imatinib, present results confirm the efficacy of combining Imatinib and IFN-α and further support investigating treatment approaches employing these two drugs.

Model-based decision rules reduce the risk of molecular relapse after cessation of tyrosine kinase inhibitor therapy in chronic myeloid leukemia

Blood ◽  
2013 ◽  
Vol 121 (2) ◽  
pp. 378-384 ◽  
Author(s):  
Matthias Horn ◽  
Ingmar Glauche ◽  
Martin C. Müller ◽  
Rüdiger Hehlmann ◽  
Andreas Hochhaus ◽  
...  
Keyword(s):  
Chronic Myeloid Leukemia ◽  
Myeloid Leukemia ◽  
Kinase Inhibitor ◽  
Decision Rules ◽  
Patient Specific ◽  
Individual Risk ◽  
Molecular Response ◽  
Treatment Cessation ◽  
Tyrosine Kinase Inhibitor Therapy ◽  
The Individual

Abstract Molecular response to imatinib (IM) in chronic myeloid leukemia (CML) is associated with a biphasic but heterogeneous decline of BCR-ABL transcript levels. We analyzed this interindividual heterogeneity and provide a predictive mathematical model to prognosticate the long-term response and the individual risk of molecular relapse on treatment cessation. The parameters of the model were determined using 7-year follow-up data from a randomized clinical trial and validated by an independent dataset. Our model predicts that a subset of patients (14%) achieve complete leukemia eradication within less than 15 years and could therefore benefit from discontinuation of treatment. Furthermore, the model prognosticates that 31% of the patients will remain in deep molecular remission (MR5.0) after treatment cessation after a fixed period of 2 years in MR5.0, whereas 69% are expected to relapse. As a major result, we propose a predictor that allows to assess the patient-specific risk of molecular relapse on treatment discontinuation and to identify patients for whom cessation of therapy would be an appropriate option. Application of the suggested rule for deciding about the time point of treatment cessation is predicted to result in a significant reduction in rate of molecular relapse.

How I treat chronic myeloid leukemia in the imatinib era

Blood ◽  
2007 ◽  
Vol 110 (8) ◽  
pp. 2828-2837 ◽  
Author(s):  
John M. Goldman
Keyword(s):  
Chronic Myeloid Leukemia ◽  
Initial Treatment ◽  
Myeloid Leukemia ◽  
Chronic Phase ◽  
Response To Treatment ◽  
Molecular Response ◽  
Newly Diagnosed ◽  
Allogeneic Transplant ◽  
Reduced Intensity Conditioning ◽  
Log Reduction

AbstractAlthough it is now generally accepted that imatinib is the best initial treatment for patients newly diagnosed with chronic myeloid leukemia (CML) in chronic phase, a number of questions remain unanswered. For example, (1) Is imatinib the best initial treatment for every chronic-phase patient? (2) At what dose should imatinib be started? (3) How should response to treatment be monitored? (4) For how long should the drug be continued in patients who have achieved and maintain a complete molecular response? (5) How does one handle a patient who achieves a 2-log but not a 3-log reduction in BCR-ABL transcripts? (6) How should response or failure be defined? (7) For the patient deemed to have failed imatinib, should one offer dasatinib or nilotinib? (8) For the patient who has failed imatinib but has a possible allogeneic transplant donor, should one offer dasatinib or nilotinib before recommending a transplantation? (9) Should the transplantation be myeloablative or reduced intensity conditioning? (10) How should one treat the patient who relapses after allografting? This paper will address these issues, many of which cannot yet be answered definitively.

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