Chromosome-positive Chronic Myeloid Leukemia Patients Research Articles

TKI Dose Optimization Based on Therapeutic Drug Monitoring（TDM) with Encouraging Outcomes and Well-Tolerated for Chronic Myeloid Leukaemia Patients

Background Imatinib, nilotinib, and dasatinib are tyrosine kinase inhibitors (TKIs) that have become first-line treatments for Philadelphia chromosome-positive chronic myeloid leukemia (CML). Series studies indicated TKIs had a high therapeutic index, which led to the registration of these medications at fixed doses. Therapeutic drug monitoring (TDM) is a strategy for dosage optimization to provide individual treatment through dose adjustment to improve efficacy or avoid TKI-related adverse events (AEs). Objective We prospectively analyzed the outcome based on trough plasma concentrations (Cmin) to manage TKI dosage optimization during imatinib, nilotinib, and dasatinib therapy in patients with CML by 12 months. The primary efficacy endpoint was the rate of MMR at 12 months, the secondary endpoints included the cumulative rate of significant AEs defined as grade 3/4 fluid retention, all grade pleural effusion and pulmonary hypertension, grade 3/4 bilirubin increased, and grade 3/4 hematological toxicity related to TKIs within the first 12 months of therapy. Methods We examined 204 CML patients treated with imatinib, nilotinib, or dasatinib in the first line for CML-CP. We used high-performance liquid chromatography-tandem mass spectrometry (UPLC/MS-MS) to detect the Cmin of TKIs. Dasatinib or imatinib Cmin (24±3h post-dose) and nilotinib Cmin (12±3 h post-dose) were assessed after 7~10 days of therapy. We set the Cmin of imatinib at 1000~1500 ng/mL and that of nilotinib at 600~800 ng/mL, dasatinib at 1~3 ng/ml, respectively. Results Imatinib group (n = 67), Nilotinib group (n = 72), and Dasatinib group (n = 65), respectively. The initial dose of imatinib was 400mg qd, based on Cmin of imatinib was 900~1100ng/mL, there were 17 patients with dose reduction(1 case with 100mg qd, 5 cases with 200mg qd, 11 cases with 300mg qd) and 2 patients increased dose to 500mg qd; The initial dose of nilotinib was 300mg bid, based on Cmin of imatinib was 600~800ng/mL, there were 21 patients with dose reduction( 4 cases with 150mg bid, 16 cases with 450mg daily, 1 cases with 150mg qd) and 1 patients increased to 400mg bid; the initial dose of dasatinib was 100mg qd, based on Cmin of dasatinib was1~3 ng/ml, there were 32 patients with dose reduction(1 case with 20mg qd, 4 cases with 40mg qd, 20 cases with 50mg qd, 7 cases with 70mg qd ). Among the patients treated with imatinib, dasatinib, and nilotinib, no statistically significant associations were observed between gender, age, ELT scores, and plasma trough concentration (p>0.05). Early molecular reaction (EMR BCR: ABL(IS) <10%) was achieved by 83.6% (95% confidence interval [CI], 74.6%-92.5%) in the imatinib group, 87.7% (95% CI, 80.0%-95.4%) in the nilotinib group, and 83.3% (95% CI, 75.0%-91.7%) in the dasatinib group of patients at 3 months. The incidence of MMR at 12 months was 82.1% (95% CI, 73.1%-93.0%) in the imatinib group, 73.8% (95% CI, 64.6%-84.6%) in the nilotinib group, and 75.0% (95% CI, 65.3%-84.7%) in the dasatinib group, respectively. The cumulative incidence of grade 3/4 hematological toxicity was 7.8% (16/204), all-grade pleural effusion was 23.1% (15/65) in the dasatinib group, grade 3/4 bilirubin increased was 6.9% (5/72) in the nilotinib group, and there were no patients with pulmonary hypertension. Conclusion There are large individual differences in plasma trough concentrations in CML patients taking TKIs, the TKI dosage should be adjusted based on target plasma concentrations to maximize efficacy and minimize the incidence of adverse events.

Comparable b2a2/e13a2 and b3a2/e14a2 Reporting in BCR-ABL Assay When Calibrated By Who Is and By IVT-RNA Copy Number

Introduction: Xpert® BCR-ABL Ultra, automated cartridge-based assay for monitoring BCR-ABL transcript levels, is calibrated by WHO IS to standardize the %reporting for both b2a2/e13a2 BCR-ABL(e13a2) and b3a2/e14a2 BCR-ABL(e14a2) relative to control ABL gene in peripheral blood of patients as a standard management of Chronic Myeloid Leukemia (CML) [1]. Studies have shown differences in patients carrying e13a2 or e14a2 in molecular response to Tyrosine Kinase Inhibitor (TKI) treatment [2-4]. Therefore, it is necessary to understand if there is %reporting differences between two transcripts calibrated by WHO IS[5] and explore the calibration method using breakpoint specific RNA input copy number (CN) for accurate TKI treatment monitoring. Objectives: To establish % reporting method calculated with known CN of e13a2, e14a2 and ABL IVT-RNA within a wide CN range and compare % e13a2 and % e14a2 to WHO IS quantification system. Methods: Three IVT-RNAs, containing e13a2-ABL-BCR, e14a2-ABL-BCR and ABL-BCR, were synthesized as shown in Figure 1. Serial diluted e13a2 RNA, e14a2 RNA and ABL RNA panels were tested on Xpert BCR-ABL Ultra assay to generate individual standard curve of e13a2 Ct, e14a2 Ct and ABL Ct as a function of CN for % reporting calculation. Four levels of IVT-RNA panels with same CN of e13a2 and e14a2 were tested for breakpoint specific % reporting comparison. K562(e14a2), BV173 (e13a2) cell lysates and CML clinical samples carrying e13a2 or e14a2 transcripts were tested to evaluate the %CN reporting compared to WHO IS. Result: Good linearity demonstrated in Ct vs CN input for e13a2, e14a2 and ABL IVT-RNA (Figure2) with comparable efficiency (E) between e13a2 (E=0.992) and e14a2 (E=0.986). %e13a2 reporting was ~1.50-fold (by WHO IS) and ~1.46-fold (by %CN) higher than %e14a2, by testing IVT-RNA panel (Table1). Minor differences in %reporting observed between % CN and WHO IS for e13a2 (84.5%~110.8%) vs e14a2 (82.5%~89.5%) from cell lysates (Table2) and e13a2 (92.6%~105.5%) vs e14a2 (88.1%~92.2%) from clinical samples (Table3). Conclusions: A %CN e13a2/ABL and e14a2/ABL reporting method with known CN of IVT-RNAs has been successfully established in Xpert BCR-ABL Ultra. Both WHO IS and %CN showed very minor differences between e13a2 and e14a2 for % reporting. %CN method demonstrated comparable %reporting to WHO IS in Xpert BCR-ABL Ultra. Recent Publications 1. Dominy KM, Simon IM, Khorashad JS (2021) Evaluation of Xpert® BCR-ABL Ultra for the confirmation of BCR-ABL1 international scale conversion factors for the molecular monitoring of chronic myeloid leukaemia, Int J Lab Hematol, Feb;43(1):e31-e34. 2. Hanfstein B, Lauseker M, Hehlmann R, Saussele S, Erben P, Dietz C (2014) Distinct characteristics of e13a2 versus e14a2 BCR-ABL1 driven chronic myeloid leukemia under first-line therapy with imatinib. Haematologica.99:1441-7. 3. Jain P, Kantarjian H, Patel KP, Gonzalez GN, Luthra R, Shamanna RK (2016) Impact of BCR-ABL transcript type on outcome in patients with chronic-phase CML treated with tyrosine kinase inhibitors. Blood.127:1269-75. 4. Castagnetti F, Gugliotta G, Breccia M, Iurlo A, Levato L, Albano F (2017) The BCR-ABL1 transcript type influences response and outcome in Philadelphia chromosome-positive chronic myeloid leukemia patients treated frontline with imatinib. Am J Hematol. 92:797-805. 5. Matthew S, White HE, Hana Z, Nicholas C.P C (2022) Impact of BCR::ABL1 transcript type on RT-qPCR amplification performance and molecular response to therapy. Leukemia 36(7):1-8

Population Pharmacokinetics and Pharmacogenetics Analyses of Dasatinib in Chinese Patients with Chronic Myeloid Leukemia.

Dasatinib, a second-generation tyrosine kinase inhibitor of BCR-ABL 1, used for first-line treatment of Philadelphia chromosome-positive chronic myeloid leukemia (CML), exhibits high pharmacokinetic (PK) variability. However, its PK data in Chinese patients with CML remains rarely reported to date. Thus, we developed a population pharmacokinetic (PPK) model of dasatinib in Chinese patients and identified the covariate that could explain the individual variability of PK for optimal individual administration. PPK modeling for dasatinib was performed based on 754 plasma concentrations obtained from 140 CML patients and analysis of various genetic and physicochemical parameters. Modeling was performed with nonlinear mixed-effects (NLME) using Phoenix NLME. The finally developed model was evaluated using internal and external validation. Monte Carlo simulations were used to predict drug exposures at a steady state for various dosages. The PK of dasatinib were well described by a two-compartment with a log-additive residual error model. Patients in the current study had a relatively low estimate of CL/F (126 L/h). A significant association was found between the covariate of age and CL/F of dasatinib, which was incorporated into the final model. None of the genetic factors was confirmed as a significant covariate for dasatinib. The results of external validation with 140 samples from 36 patients were acceptable. Simulation results showed significantly higher exposures in elderly patients. This study's findings suggested that low-dose dasatinib would be better suited for Chinese patients, and the dosage can be appropriately reduced according to the increase of age, especially for the elderly.

Low prevalence of the BCR-ABL1 fusion gene in a normal population in southern Sarawak.

The BCR-ABL1 fusion gene is the driver mutation of Philadelphia chromosome-positive chronic myeloid leukemia (CML). Its expression level in CML patients is monitored by a real-time quantitative polymerase chain reaction defined by the International Scale (qPCRIS). BCR-ABL1 has also been found in asymptomatic normal individuals using a non-qPCRIS method. In the present study, we examined the prevalence of BCR-ABL1 in a normal population in southern Sarawak by performing qPCRIS for BCR-ABL1 with ABL1 as an internal control on total white blood cells, using an unbiased sampling method. While 146 of 190 (76.8%) or 102 of 190 (53.7%) samples showed sufficient amplification of the ABL1 gene at > 20,000 or > 100,000 copy numbers, respectively, in qPCRIS, one of the 190 samples showed amplification of BCR-ABL1 with positive qPCRIS of 0.0023% and 0.0032% in two independent experiments, the sequence of which was the BCR-ABL1 e13a2 transcript. Thus, we herein demonstrated that the BCR-ABL1 fusion gene is expected to be present in approximately 0.5-1% of normal individuals in southern Sarawak.

Neferine in the LotusPlumule Potentiates the Antitumor Effect of Imatinib in Primary Chronic Myeloid Leukemia Cells In Vitro.

Imatinib, the prototype BCR-ABL tyrosine kinase inhibitor (TKI), is the first-line treatment for Philadelphia chromosome-positive chronic myeloid leukemia (CML) in the chronic phase. However, a subgroup of patients exhibit poor response or experience relapse. This issue may be overcome by combination therapy using natural compounds. Neferine, a major bisbenzylisoquinoline alkaloid extracted from "lotus plumule" (seed embryo of lotus) commonly used in traditional Chinese medicine and tea, was used herein in the combination treatment of CML. The MTT assay showed that neferine exerted cytotoxicity in primary CML cells in a dose-dependent manner. Moreover, low concentrations of neferine (4 and 8 µM) sensitized primary CML cells to imatinib (CI < 1), and significantly decreased its IC50 from 0.70 ± 0.10 to 0.32 ± 0.06 µM and 0.16 ± 0.02 µM, respectively. Cotreatment of neferine and imatinib significantly decreased the expression of BCR-ABL protein and its molecular chaperone heat shock protein 90 (Hsp90) mRNA and protein levels, and further decreased phospho-extracellular regulated protein kinase 1/2 (p-Erk1/2) and myeloid cell leukemia (Mcl-1) expression. These results suggest that neferine might be a potential imatinib sensitizer in CML treatment. PRACTICAL APPLICATION: In China, Lotus plumule, the green embryo of lotus, is used as a tea and as a source of herbal medicine in the treatment of anxiety, insomnia, spermatorrhea, and thirst. Additional, neferine, a bisbenzylisoquinoline alkaloid extracted from lotus plumule has been shown to have antitumor potential. Herein, the effect of neferine and imatinib cotreatment on primary CML cells obtained from CML patients was assessed, with a synergisticeffect being observed between the two compounds. Therefore, neferine might be a promising natural compound to potentiate imatinib in CML patients.

Long-term patient-reported outcomes from an open-label safety and efficacy study of bosutinib in Philadelphia chromosome-positive chronic myeloid leukemia patients resistant or intolerant to prior therapy.

BACKGROUNDHealth‐related quality of life (HRQOL) in patients with chronic‐phase chronic myeloid leukemia (CML) is important because of the requirement for long‐term treatment. This study assessed HRQOL in bosutinib‐treated patients with Philadelphia chromosome–positive CML and resistance or intolerance to 1 (chronic‐phase second‐line [CP2L]) or more (chronic‐phase third‐line [CP3L]) tyrosine kinase inhibitors who had 264 weeks or more of follow‐up (ClinicalTrials.gov identifier NCT00261846).METHODSPatient‐reported HRQOL was assessed with the EuroQol 5‐Dimensions Questionnaire (EQ‐5D) and the Functional Assessment of Cancer Therapy–Leukemia (FACT‐Leu).RESULTSIn total, 284 and 119 patients composed the CP2L and CP3L cohorts, respectively. At treatment completion, more than 50% of the patients in the CP2L and CP3L cohorts completed the EQ‐5D and FACT‐Leu assessments. The EQ‐5D and EQ‐5D visual analog scale scores were stable in both cohorts throughout treatment. The mean FACT‐Leu scores were generally stable over time but were lower in magnitude in the CP3L cohort versus the CP2L cohort. The FACT‐Leu scale scores of a subset of patients with chronic diarrhea (CP2L, n = 101; CP3L, n = 30) were similar to the scores of the larger cohorts. Minimally important differences (MIDs) from baseline for the FACT‐Leu scale scores were observed for the following: emotional well‐being (EWB), Functional Assessment of Cancer Therapy–General (FACT‐G) Total, FACT‐Leu Total, and Functional Assessment of Cancer Therapy Trial Outcome Index (FACT‐TOI) in the CP2L cohort and FACT‐Leu Total in the CP3L cohort. Among patients with chronic diarrhea, MIDs were observed for EWB, FACT‐G Total, FACT‐Leu Total, and FACT‐TOI in the CP2L cohort and for EWB, FACT‐G Total, and FACT‐Leu Total in the CP3L cohort.CONCLUSIONSHRQOL was maintained with long‐term bosutinib treatment for patients with CP2L and CP3L CML. Cancer 2018;124:587‐95. © 2017 The Authors. Cancer published by Wiley Periodicals, Inc. on behalf of American Cancer Society. This is an open access article under the terms of the Creative Commons Attribution‐NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.

Female and Elderly Chronic Myeloid Leukemia Patients Often Do Not Receive an Adequate TKI Treatment

IntroductionFor one and a half decade, tyrosine kinase inhibitors (TKI) have been the standard treatment for Philadelphia chromosome-positive chronic myeloid leukemia (CML). Recent studies have shown that elderly patients above 65 years benefit from a TKI treatment too. Since there were sporadic reports that elderly CML-patients receive less often TKI the aim of our study was to determine if the prescribing of TKI for CML in Germany follows the current recommendations, especially in the elderly. This was done by analyzing population-based claims data from the Bavarian Association of Statutory Health Insurance Physicians (Kassenärztliche Vereinigung Bayerns).MethodsData on ICD-10 codes as well as prescribed medication were available for about 10.5 million patients in the statutory health insurance system in Bavaria for the years 2008 to 2013. To avoid misclassification, only patients with at least two recorded diagnoses of CML over time were counted.All analyses on daily doses of TKI in this work are based on the daily doses recommended by the EMA, i.e. 400 mg/d for imatinib, 100 mg/d for dasatinib, 300 mg twice/d for nilotinib, 500 mg/d for bosutinib and 45 mg/d for ponatinib.Analyses were performed with R 3.1.0 and SPSS 22.Results1880 different CML patients were identified between 2008 and 2013.During the six years analysed, 1,431,882 daily doses of TKI were administered. The majority of TKI doses were imatinib with 1,204,025 daily doses (84%), followed by nilotinib with 145,291 daily doses (10%) and dasatinib with 81,818 daily doses (6%). The percentage of CML patients receiving TKI increased from 55% in the first quarter year of 2008 to 72% in the last quarter year of 2013.1534 patients were observed for at least four quarter years between 2008 and 2013. At median, they received 64 doses of TKI per quarter year. 1209 patients (78.8%) were treated with TKI. Only 711 patients (46.3%) received more than 67.5 daily doses, thereof 71 (4.6%) with more than 100 daily doses per quarter year. The latter are supposed to be patients with a high-dose imatinib treatment.Out of the 325 patients that did not receive any TKI, 293 (90.2%) were treated with Hydroxyurea, only 14 patients (4.3%) received Interferon.When stratifying for age group and sex, we found that for the males, the median number of daily doses in patients that actually received TKI sank from 88 doses per quarter year for patients younger than 20 years to a median of 72 daily doses for patients of 80 years and older. For women the median number of daily TKI doses was generally lower than for men. Here the highest median number of daily doses per quarter year was reached between 50 and 69 years with 80 doses and decreased to 58 in the oldest patients. However, the percentage of patients that did not receive any TKI increased steadily with age. While all patients below 20 years received TKI, 46% of the males and 43% of the women in the oldest age group of 80 years and above did not get any TKI treatment.In total, 429 (28.0%) of the patients received any second-generation TKI. The use of second-generation TKI did not depend on age or sex.DiscussionOur analyses have shown, that even in the most prosperous part of a highly developed country with an extensive statutory health insurance system, still a considerable number of CML patients did not receive the adequate treatment. We found that especially elderly patients were often treated with Hydroxyurea only. There might be various reasons, as especially elderly patients might suffer from other malignancies, but also an underestimation of the patient's remaining life expectancy by the physician, resulting in withholding the expensive treatment to the elderly. Besides, it was noteworthy that women received a lower median dose than men.As it has been repeatedly shown that too low doses of treatment with TKI are accompanied with less therapeutic success, patients and physicians need to be motivated to take more care for administering the required doses over time. It has been shown that this may even be cost effective as poor adherence with TKI treatment results in higher health care costs. DisclosuresNo relevant conflicts of interest to declare.

Characterization of a novel variant BCR–ABL1 fusion transcript in a patient with chronic myeloid leukemia: Implications for molecular monitoring

Molecular monitoring of BCR–ABL1 transcript levels using quantitative polymerase chain reaction is an essential part of the modern management of chronic myeloid leukemia patients treated with tyrosine kinase inhibitors. Establishing the diagnostic BCR–ABL1 fusion transcript is necessary in order to select appropriate primers and probes for such monitoring. A case is described in which quantitative polymerase chain reaction failed to detect the presence of BCR–ABL1 fusion transcript in a Philadelphia chromosome-positive chronic myeloid leukemia patient. Further investigation demonstrated a novel in-frame BCR–ABL1 fusion transcript with a breakpoint in BCR exon 13 and insertion of a sequence of ABL1 intron 1, therefore enabling subsequent molecular monitoring. This case highlights the requirement for characterization of the BCR–ABL1 transcript type at chronic myeloid leukemia diagnosis. Issues concerning standardized methodological approaches and interpretation of transcript levels in such rare cases are discussed.

SY13-2 - Therapeutic drug monitoring of imatinib

Imatinib is tyrosine kinase inhibitor (TKI) that has become first-line treatments for Philadelphia chromosome-positive chronic myeloid leukemia (CML). In Japanese CML patients, the coefficient of variation (CV) in the inter-patient imatinib plasma trough concentration (C0) after taking a 400 mg standard daily dose ranged from 38.2% to 62.9%. In the combined data set from 6 clinical studies, the rate of a major molecular response achievement is significantly higher for patients with an imatinib C0 above 1,000 ng/mL than for patients with a C0 less than 1,000 ng/mL (odds ratio, 2.48, P < 0.0001). Therefore, the target imatinib C0 should be set above 1,000 ng/mL. However, dose adjustment according to the target C0 should not be evaluated with an imatinib C0 of only one point, because variability of the intra-patient imatinib C0 CV is quite large ranging from 8.4% to 49.3%. The mean imatinib C0 for 3 months or using multiple C0 points should be assessed for each patient treated with imatinib. After one year, the imatinib C0 might be assessed at 6-month intervals, as well as each time a potentially interacting drug is introduced or withdrawn or if poor adherence to treatment is suspected. Patients with a mean imatinib C0 above 1,000 ng/mL not exhibiting a positive effect (non-responders) might switch to a 2nd generation TKI therapy. In TKI therapy for CML patients, TDM is a new strategy that provides a method for optimizing the drug dosage to obtain faster and deeper clinical responses. Although at present clinicians consider the next pharmacotherapy from clinical responses such as efficacy or adverse events obtained from a fixed dosage of TKI, we suggest that the drug dosage be adjusted based on target concentration to maximize efficacy and minimize the incidence of adverse events. Consequently, TKI therapy could be continued for a longer time, and the periodic measurement of imatinib C0 might lead to the feasibility of discontinuing imatinib in the future.

Therapeutic drug monitoring of imatinib, nilotinib, and dasatinib for patients with chronic myeloid leukemia.

Imatinib, nilotinib, and dasatinib are tyrosine kinase inhibitors (TKIs) that have become first-line treatments for Philadelphia chromosome-positive chronic myeloid leukemia (CML). According to European LeukemiaNet recommendations, the clinical response of CML patients receiving TKI therapy should be evaluated after 3, 6, and 12 months. For patients not achieving a satisfactory response within 3 months, the mean plasma concentration for the three months of TKI administration must be considered. In TKI therapy for CML patients, therapeutic drug monitoring is a new strategy for dosage optimization to obtain a faster and more effective clinical response. The imatinib plasma trough concentration (C₀) should be set above 1000 ng/mL to obtain a response and below 3000 ng/mL to avoid serious adverse events such as neutropenia. For patients with a UGT1A1*6/*6, *6/*28, or *28/*28 genotype initially administered 300-400 mg/d, a target nilotinib C₀ of 500 ng/mL is recommended to prevent elevation of bilirubin levels, whereas for patients with the UGT1A1*1 allele initially administered 600 mg/d, a target nilotinib C₀ of 800 ng/mL is recommended. For dasatinib, it is recommended that a higher Cmax or C₂ (above 50 ng/mL) to obtain a clinical response and a lower C₀ (less than 2.5 ng/mL) to avoid pleural effusion be maintained by once daily administration of dasatinib. Although at present clinicians consider the next pharmacotherapy from clinical responses (efficacy/toxicity) obtained by a fixed dosage of TKI, the TKI dosage should be adjusted based on target plasma concentrations to maximize the efficacy and to minimize the incidence of adverse events.

Overall Survival and Prognosis In Patients With First-Line Imatinib Treatment Under Consideration Of Death Due To Any Cause and Death Due To Chronic Myeloid Leukemia Only

IntroductionAs a part of the European Treatment and Outcome Study (EUTOS), the IN-study registry collected data on patients with Philadelphia chromosome-positive chronic myeloid leukemia (CML) enrolled in prospective clinical trials. Patients had to have been in chronic phase (CP) and imatinib-based treatment been started within half a year after diagnosis. Meanwhile, median observation time seemed to allow the analysis of overall survival (OS) and a possible identification of prognostic factors. AimsFor OS with death due to any cause and for cumulative incidences of mortality (CIM) due to CML only, we planned to describe probabilities as well as to analyze the prognostic influence of the candidate factors age, sex, spleen enlargement, hemoglobin, platelets, leukocytes, and percentages of blasts, eosinophils, and basophils in peripheral blood (PB) on the respective probabilities. MethodsSurvival of patients fulfilling the inclusion criteria was censored at the time of allogeneic stem cell transplantation (SCT) in first CP. Allowing any cause of death as an event, prognostic influence on OS was estimated with multiple Cox regression allowing fractional polynomials for continuous variables. These results were opposed to the findings when cause of death was restricted to CML only and then analyzing a) cause-specific hazards by standard Cox regression and b) subdistribution hazards of the CIM with the Fine and Gray model. All prognostic factors were measured at baseline. Level of significance was 0.05. ResultsPatients joined study groups in Germany, France, Italy, Spain, the Netherlands, or the Nordic study group. Analyses were based on 2127 patients of five studies with similar follow-up patterns. Median observation time was 6.4 years. Eight-year survival probability was 89% [95%-confidence interval (CI): 87-90%]. Allogeneic SCT in first CP was performed in 94 patients (4%). The sample for regression analysis comprised 2067 patients with complete data for the candidate prognostic factors. Their median age was 51 years [range: 18-88], 60% were male.Altogether, 187 patients died. With death due to any cause as event, higher age and bigger spleen size enlargement (cm below costal margin) significantly reduced OS probabilities. Besides, multiple modeling also suggested that the interaction between sex and hemoglobin had a significant influence on survival. Females with lower hemoglobin values had less favorable survival probabilities while hemoglobin showed no effect in males.Judged by experienced physicians, in 89 cases (48% of 187), cause of death was CML-related (not related to CML: n=87 (47%), unknown cause: n=11 (6%)). Eight-year CIM due to CML was 5% [95%-C.I.: 4-6%] and 6% [95%-C.I.: 5-8%] due to other causes.Cause-specific Cox regression with death due to CML as the only event resulted in the same prognostic factors as for the analysis with any cause of death as event – apart from one exception: now, higher percentages of blasts in PB had a significantly negative effect, too.The analysis of the influence of prognostic factors on the CIM due to CML via the Fine and Gray model, which took the competing risk of dying due to other cause (87+11=98) into account, led to the same prognostic factors as for the cause-specific Cox model where death due to other cause was censored. ConclusionsMedian observation time and the number of events actually allowed a reasonable modeling of OS probabilities and CIM, even though the restriction on the cause of death due to CML reduced the number of events by about 50% in the second case. Also when considering only deaths due to CML, age remained significant and seems to be a true prognostic factor for long-term survival outcome when suffering from CML. However, age did not become part of the EUTOS score investigating the influence of various factors on the achievement of complete cytogenetic remission within 18 months (Hasford et al., Blood 2011) and this showed that imatinib-based treatment helps in any age. After all, significantly higher but still relatively low hazards of dying due to CML in older age result in small absolute numbers. It appears to be conclusive that blasts in PB influence OS probabilities and CIM due to CML, as blasts in PB became also part of the Sokal and the Euro Score, both developed at times when OS probabilities were much lower, with most CML patients actually dying of CML. All findings will be checked in independent patient data. Disclosures:Pfirrmann:Novartis: Consultancy. Saussele:Pfizer: Honoraria; BMS: Honoraria, Research Funding, Travel, Travel Other; Novartis: Honoraria, Research Funding, Travel Other. Baccarani:Novartis: Research Funding. Lindörfer:Novartis: Research Funding. Hoffmann:Novartis Oncology: Research Funding. Castagnetti:Novartis: Consultancy, Honoraria; Bristol-Myers Squibb: Consultancy, Honoraria. Hehlmann:Novartis: Research Funding.

Prospective Histomorphometric and DXA Evaluation of Bone Remodeling in Imatinib-Treated CML Patients: Evidence for Site-Specific Skeletal Effects

Imatinib is a tyrosine kinase inhibitor that has been successfully used to treat Philadelphia chromosome-positive chronic myeloid leukemia (CML) and Kit(+) gastrointestinal stromal tumors. We have previously shown that imatinib therapy is associated with an increase in trabecular bone volume. In the present study, we performed a prospective analysis of bone indices in imatinib-treated CML patients to determine the mechanism responsible for this altered bone remodeling. DESIGN, PATIENTS, AND INTERVENTION: This study assessed the effects of high-dose (600 mg/d) imatinib on bone parameters in newly diagnosed chronic-phase Philadelphia chromosome-positive CML patients (n = 11) enrolled in the TIDEL II study. At baseline and after 6, 12, and 24 months of treatment, serum markers of bone remodeling were quantitated, dual-energy x-ray absorptiometry analysis of bone mineral density (BMD) was carried out, and a bone biopsy was collected for histological and micro-computed tomography analysis. Our studies show that the increase in trabecular bone volume and trabecular thickness after imatinib treatment was associated with a significant decrease in osteoclast numbers, accompanied by a significant decrease in serum levels of a marker of osteoclast activity. In contrast, osteoblast numbers were not altered by up to 24 months of imatinib treatment. Notably, we also found that imatinib caused a site-specific decrease in BMD at the femoral neck. These data suggest that imatinib therapy dysregulates bone remodeling, causing a generalized decrease in osteoclast number and activity that is not counterbalanced by a decrease in osteoblast activity, leading to increased trabecular bone volume. Further long-term investigations are required to determine the causes and consequences of the site-specific decrease in BMD at the femoral neck.

Author reply to Fujimi et al

We appreciate the interest of Fujimi et al. in our pharmacokinetic and exposure-response analysis of nilotinib in patients with newly diagnosed Philadelphia chromosomepositive chronic myeloid leukemia (CML) [1]. In their letter to the editor, Fujimi et al. [2] described a patient with CML who, after failure of two prior tyrosine kinase inhibitors (TKIs), imatinib and dasatinib, achieved complete cytogenetic response within 15 months on nilotinib. The authors’ observation about a potential role of bile acid on the absorption of nilotinib is consistent with our knowledge that nilotinib has a low aqueous solubility and that its in vivo dissolution and absorption may be enhanced by the presence of bile salts. While we agree with the authors’ conclusion that therapeutic drug monitoring of nilotinib may be useful in particular situations, such as the case presented, such a conclusion cannot be automatically applied to the general practice of CML therapy with nilotinib for the following reasons. Our analysis was based on pharmacokinetic data from 542 patients with newly diagnosed CML, whereas the case report by Fujimi et al. concerned a CML patient who experienced failure of two prior TKI therapies. Although the pharmacokinetic profile of nilotinib is unlikely to be altered by disease status, the pharmacokinetic–pharmacodynamic relationship may differ in these patient groups. While the analysis described in our manuscript showed a lack of significant correlation between nilotinib exposure and molecular response in newly diagnosed patients with CML, we have observed that lower nilotinib trough concentration (Cmin) significantly correlated to longer time to complete cytogenetic response and major molecular response, and shorter time to progression in patients with imatinib-resistant or -intolerant CML [3]. There was also a trend toward lower response rates in patients with lower versus higher nilotinib Cmin. These results suggest that conclusions from one study population (e.g., newly diagnosed CML) can not be automatically extrapolated to another (e.g., imatinib-resistant or -intolerant CML). The interand intra-patient variability in the pharmacokinetics of a drug is attributed to several factors. Despite the lower bioavailability of nilotinib compared with imatinib and dasatinib, inter-patient pharmacokinetic variability was comparable for these three TKIs in clinical trials [32–64 % in nilotinib area under the curve (AUC), 49 % in imatinib AUC, 56 % in dasatinib peak concentration (Cmax)] [4]. In situations where physiological changes or surgical procedures are involved, or significant drug–drug interactions or patient nonadherence are suspected, wider interand/or intra-patient variability would be expected. As already discussed in our manuscript, our analysis was based on the data obtained under a well-controlled clinical trial setting. The role of blood level testing in the special circumstances that may arise in the clinic, such as those mentioned above, needs to be further defined with additional studies. The case report by Fujimi et al. illustrated one of these special circumstances. R. A. Larson University of Chicago, Chicago, IL, USA

Clinical Trials in Chronic Myeloid Leukemia

The introduction of the tyrosine kinase inhibitor (TKI) imatinib in the treatment of Philadelphia chromosome-positive chronic myeloid leukemia (CML) has substantially improved the outcome of CML patients. Despite the positive results, problems and questions remained. This was the rationale to setup trials for treatment optimization, where imatinib was administered in higher dose and/or in combination with other therapy but where also new and potentially more efficacious second-generation TKI, nilotinib and dasatinib, were investigated. This review summarizes data of recently published first-line studies with the standard treatment imatinib 400 mg as one study arm. Results of randomized comparisons to higher-dose imatinib treatment, nilotinib or dasatinib are discussed. With regard to outcome interpretation, general aspects on statistical issues and endpoint definitions are put into focus. Considering decidedly increased longevity thanks to TKI treatment, future research should include the evaluation of the quality of life (QoL). Relating also to QoL, safe ways of drug discontinuation need to be investigated.

Identifying High Symptom Burden in Patients with Chronic Myeloid Leukemia on Tyrosine Kinase Inhibitor Therapy

Abstract 3138 Background:Patient report of symptom burden from Philadelphia chromosome-positive chronic myeloid leukemia (CML) and its treatment is scarce. Symptom burden is the combined impact of symptoms from disease and treatment on daily functioning. Lack of symptom recognition may result in failure to address symptoms and maximize patient functioning and treatment adherence. The purposes of this study are to develop a valid and reliable patient questionnaire for measuring CML symptom burden and to describe symptom burden over 1 year. This abstract reports intermediate results of the longitudinal symptom burden of CML. Methods:160 patients with CML rated the 20 symptom items (13 core cancer and 7 CML-specific symptom items) and 6 interference items of the M. D. Anderson Symptom Inventory for CML (MDASI-CML), on a 0-to-10 scale (0 = not present or no interference; 10 = as bad as can be imagined or complete interference) every 2 weeks using interactive voice response (IVR) telephone technology. Information on performance status, quality of life, disease history, and treatment was collected at study entry. The longitudinal symptom burden of CML and associated factors are reported using descriptive statistics, t-tests, and group-based trajectory and logistic regression modeling. Results:As of May 31, 2011, 160 patients had completed the MDASI-CML for 6 months; 35 patients (22%) had more that 50% data missing and were excluded from analysis. Of the remaining 125 patients, average age at study entry was 50.7 years (standard deviation [SD] = 13.2), 54% were female, 98% had chronic phase (CP) CML, 94% were receiving tyrosine kinase inhibitor (TKI) therapy, average time on current TKI therapy was 44.2 months (SD = 35.7), 2% began TKI therapy at study entry, and 99% had a clinician-rated ECOG performance status of 1 or less. The 5 most severe symptoms reported by the patients were fatigue (mean = 2.73, SD = 2.38), drowsiness (2.17, 2.26), muscle soreness and cramping (2.09, 2.36), disturbed sleep (2.03, 2.37), and difficulty remembering (1.68, 1.88). Trajectory analysis of a composite of the 5 most severe symptoms showed that patients could be divided into 2 groups reporting significantly more (48 patients, 38%) or less (77 patients, 62%) symptom severity across the 6 months of assessment (Figure 1). Average severity of all the individual symptom and interference items as well as the composite means of the top 5 symptoms, the 13 core symptoms, the 7 CML-specific symptoms, and the 6 interference items were significantly different between the groups (all p<0.01). Multivariate logistic regression modeling showed that being unmarried, higher severity of fatigue, difficulty sleeping, difficulty remembering, lack of appetite, easy bruising and bleeding, and lower severity of diarrhea at the time of study entry were independent factors significantly predicting membership in the high symptom severity group (Table 1). No other demographic or disease and treatment variables significantly predicted group membership. [Display omitted] Implications:A subset of patients (approximately one third) with CML primarily in CP receiving TKI therapy experiences more severe symptoms and needs special attention to symptom management. A single assessment (the MDASI-CML) can identify patients who experience chronically higher symptom burden and who need interventions to ameliorate symptoms, maintain daily functioning, and encourage treatment adherence. More analysis and research is needed to further delineate the symptom burden of CML and its treatment, understand the effects of symptom burden on treatment adherence, and develop effective interventions to relieve more-severe symptoms.TableFactors in CML patients predicting membership in high-symptom severity group.OR*P-Value#Lower CI TFU1-3Upper CI TFU1-3Unmarried13.744.0171.585119.154Fatigue1.616.0021.1842.204Disturbed Sleep1.676.0081.1462.451Difficulty Remembering1.543.0271.0492.268Lack of Appetite2.424.0251.1165.263Diarrhea.594.012.396.890Easy Bruising/Bleeding1.517.0151.0832.124*OR = odds ration;#P-value = probability value;##CI = confidence interval Disclosures:Williams:Novartis: Research Funding. Ault:Novartis: Speakers Bureau; Bristol-Myers Squibb: Speakers Bureau. Cortes:Novartis: Consultancy; Novartis: Research Funding; BMS: Consultancy, Research Funding; Ariad: Consultancy, Research Funding; Pfizer: Consultancy, Research Funding.

Safety and efficacy of bosutinib (SKI-606) in chronic phase Philadelphia chromosome–positive chronic myeloid leukemia patients with resistance or intolerance to imatinib

AbstractBosutinib, a dual Src/Abl kinase inhibitor, has shown potent activity against chronic myeloid leukemia (CML). In this phase 1/2 study we evaluated bosutinib in patients with chronic phase imatinib-resistant or imatinib-intolerant CML. Part 1 was a dose-escalation study to determine the recommended starting dose for part 2; part 2 evaluated the efficacy and safety of bosutinib 500 mg once-daily dosing. The study enrolled 288 patients with imatinib-resistant (n = 200) or imatinibintolerant (n = 88) CML and no other previous kinase inhibitor exposure. At 24 weeks, 31% of patients achieved major cytogenetic response (primary end point). After a median follow-up of 24.2 months, 86% of patients achieved complete hematologic remission, 53% had a major cytogenetic response (41% had a complete cytogenetic response), and 64% of those achieving complete cytogenetic response had a major molecular response. At 2 years, progression-free survival was 79%; overall survival at 2 years was 92%. Responses were seen across Bcr-Abl mutants, except T315I. Bosutinib exhibited an acceptable safety profile; the most common treatment-emergent adverse event was mild/moderate, typically self-limiting diarrhea. Grade 3/4 nonhematologic adverse events (> 2% of patients) included diarrhea (9%), rash (9%), and vomiting (3%). These data suggest bosutinib is effective and tolerable in patients with chronic phase imatinib-resistant or imatinib-intolerant CML. This trial was registered at http://www.clinicaltrials.gov as NCT00261846.

Therapeutic Drug Monitoring of Imatinib for Chronic Myeloid Leukemia Patients in the Chronic Phase

Imatinib is approved as a first-line treatment for Philadelphia chromosome-positive chronic myeloid leukemia (CML). Because of the variability in imatinib exposure among patients, therapeutic drug monitoring to maintain a plasma threshold level of about 1,000 ng/ml would be beneficial during imatinib therapy. Imatinib pharmacokinetics are influenced by body weight, comedication and pharmacogenetic factors, and the drug is excreted into the bile by the breast cancer resistance protein (ABCG2 gene). To attain the plasma threshold of approximately 1,000 ng/ml, the daily dose for patients with the ABCG2 421C/C genotype should be 400 mg; for patients with the 421C/A or 421A/A genotype, the dose should be 300 mg. Knowledge of the ABCG2 421 genotype could be useful when making dosing decisions aimed at achieving the optimal imatinib exposure. A therapeutic drug monitoring service should be routinely provided to CML patients taking imatinib. For CML patients who have an imatinib trough level of 1,000 ng/ml but lack a sufficient clinical response, switching to another tyrosine kinase inhibitor is recommended.

Minimal Cross-Intolerance Between Nilotinib and Imatinib in Patients with Imatinib-Intolerant Chronic Myeloid Leukemia in Chronic Phase (CML-CP) or Accelerated Phase (CML-AP)

Background: Nilotinib is a rationally designed, potent and highly selective BCR-ABL kinase inhibitor with significant clinical efficacy in the treatment of patients with Philadelphia chromosome-positive chronic myeloid leukemia patients in chronic (CML-CP) or accelerated phase (CML-AP) who are resistant or intolerant to prior therapy including imatinib. This subanalysis of the phase 2 registration study of nilotinib was designed to examine the occurrence of cross-intolerance to nilotinib in patients with prior intolerance to imatinib.Methods: Imatinib intolerance was defined as discontinuation of imatinib due to grade 3/4 adverse events (AEs) or persistent (>1 month) or recurrent (recurred >3 times) grade 2 AEs despite optimal supportive care. Additionally, patients with major cytogenetic response (MCyR) at baseline were excluded from the trial. Cross-intolerance between nilotinib and imatinib was defined as treatment with nilotinib and occurrence (regardless of causality) of grade 3/4, or persistence or recurrent grade 2, of the same AE(s) that previously led to discontinuation of imatinib therapy. Nilotinib was dosed at 400mg twice daily with the option to escalate to 600 mg twice daily for lack of response.Results: Ninety-five of 321 (30%) CML-CP patients and 27 of 138 (20%) CML-AP patients were included in this subanalysis of cross-intolerance following imatinib intolerance. Patients experiencing multiple reasons for imatinib intolerance were counted for each AE category and these included patients (8 CML-CP, 3 CML-AP) with unusual symptoms during imatinib therapy, none of these patients discontinued nilotinib due to the same AE. Median dose intensity for nilotinib (CML-CP 688mg/day, range 151–800; CML-AP 769mg/day range 184–1149) closely approximated the planned dose of 800mg/day. Among these patients, 64% of CML-CP and 52% of CML-AP patients experienced dose interruptions, however, the median cumulative duration of dose interruptions were short (CML-CP 24 days, range 1–301; CML-AP 17 days, range 4–234). Of the 72 patients (57 CML-CP, 15 CML-AP) who discontinued imatinib due to non-hematologic AEs, 3/72 (4%) experienced same persistent grade 2 AEs, only 1 patient (1%) experienced a recurrence of same grade 3/4 AE during nilotinib therapy, and none discontinued nilotinib due to cross intolerance. Approximately one-third of patients were imatinib intolerant due to hematologic AEs. Of 39 patients (30 CML-CP, 9 CML-AP) with hematologic intolerance to imatinib, 3/39 (8%) experienced same persistent grade 2 hematologic AEs, 20/39 (51%) of patients experienced a recurrence of same grade 3/4 AEs during nilotinib therapy, however, only 7 (18%) discontinued nilotinib and all occurred in CML-CP patients due to thrombocytopenia. Nilotinib therapy exhibited significant efficacy in imatinib-intolerant patients. Among the imatinib-intolerant patients included in this subanalysis who did not have complete hematologic response (CHR) at baseline, 90% of patients with CML-CP and 37% with CML-AP achieved a CHR on nilotinib therapy. Among all imatinib-intolerant patients included in this subanalysis, MCyR was achieved by 63% and 32% of patients with CML-CP and CML-AP, respectively; CCyR was achieved by 49% of CML-CP and 19% of CML-AP patients.Conclusions: These results confirm that there is minimal cross-intolerance with nilotinib in imatinib-intolerant CML-CP and CML-AP patients. Thrombocytopenia was the only laboratory abnormality leading to imatinib intolerance that has recurred with any significant frequency during nilotinib therapy.

Nilotinib in Chronic Myeloid Leukemia Patients in Chronic Phase (CMLCP) with Imatinib Resistance or Intolerance: 2-Year Follow-up Results of a Phase 2 Study.

Background: Nilotinib is a potent and highly selective BCR-ABL kinase inhibitor approved for the treatment of Philadelphia chromosome-positive chronic myeloid leukemia patients in chronic (CML-CP) or accelerated phase (CML-AP) who are resistant or intolerant to prior therapy including imatinib.Methods: This open-label, single-arm, phase 2 study was designed to evaluate the efficacy and safety of nilotinib in CML-CP patients resistant or intolerant to imatinib. Imatinib intolerant patients with prior major cytogenetic response (MCyR) on imatinib were not eligible for this trial. Nilotinib was dosed at 400 mg twice daily with the option of dose escalation to 600 mg twice daily if responses were inadequate. Rate of MCyR was the primary endpoint. Secondary endpoints included complete cytogenetic response (CCyR), complete hematological response (CHR), duration of MCyR, survival, and safety.Results: A total of 321 CML-CP patients (71% imatinib-resistant; 29% imatinib-intolerant) were evaluated. Most patients were heavily pretreated with 72% having received more than 600 mg/day of imatinib prior to study entry. Furthermore, imatinib-intolerant patients could not have achieved prior MCyR on imatinib therapy. Median duration of prior imatinib treatment was 33 months (range 0.3–95 months). Dose reductions (25%) and discontinuations (15%) due to adverse events were infrequent on nilotinib therapy and median dose intensity (788 mg/day; range 151–1112 mg/day) closely approximated the planned dose. Median duration of exposure was 465 days (15.5 months). Overall, nilotinib therapy resulted in rapid and durable hematologic and cytogenetic responses. Of all imatinib-resistant and –intolerant patients, 58% achieved MCyR (1 month median time to MCyR), with 72% of patients having a baseline CHR achieving MCyR. The MCyR rate was 63% in imatinibintolerant and 56% in imatinib-resistant patients, respectively. Overall, 42% of patients achieved a CCyR (50% in imatinib-intolerant and 39% in imatinib-resistant patients, respectively). Responses were durable, with 84% of patients maintaining their MCyR at 18 months. Estimated overall survival (OS) rates at 12 and 18 months were 95% and 91%, respectively. Nearly half of all patients (47%) were still receiving nilotinib at the time of cut-off for data analysis. Longer follow-up has not significantly changed the safety profile of nilotinib. The most frequently reported grade 3/4 biochemical laboratory abnormalities were elevated lipase (16%), hypophosphatemia (15%), hyperglycemia (12%), and elevated total bilirubin (7%). Overall, biochemical laboratory abnormalities were transient and clinically asymptomatic. Grade 3/4 non-hematologic adverse events were infrequent with rash, headache, and diarrhea occurring in only 2% of patients. No pleural or pericardial effusions were documented during nilotinib therapy. The most common grade 3/4 hematological laboratory abnormalities included neutropenia (30%), thrombocytopenia (28%), and anemia (10%). Overall, QTcF changes greater than 60 milliseconds from baseline were infrequent, occurring in only 8 patients (2.5%), and QTcF prolongation >500 milliseconds was uncommon (<1%), occurring in only 3 patients. Brief dose interruptions were sufficient to manage most adverse events.Conclusions: Nilotinib is highly effective and produces rapid and durable responses in CML-CP patients who failed prior therapy including imatinib due to resistance or intolerance and is an important treatment option for this patient population. Nilotinib is well tolerated with minimal occurrence of grade 3/4 adverse events; safety profile has not changed with longer follow-up.

Mechanisms and implications of imatinib resistance mutations in BCR-ABL.

Aside from bone marrow transplantation, a definitive cure for Philadelphia (Ph) chromosome-positive chronic myeloid leukemia (CML) has yet to be developed. Although Imatinib, the first molecularly targeted drug developed for CML has achieved a remarkable success, the emergence of resistance to this agent mitigates the prospect of a cure for this leukemia. Though a variety of resistance mechanisms can arise, in the majority of patients resistance coincides with reactivation of the tyrosine kinase activity of the BCR-ABL fusion oncoprotein. This can result from gene amplification and, more importantly, point mutations that disrupt the bind of imatinib to BCR-ABL itself. In this review, we aim to define and illuminate mechanisms of resistance and describe how drug resistance is shedding new light on kinase domain regulation. In light of recent studies and publications, it is now clear that Imatinib exerts its inhibitory action by stabilizing the inactive non ATP-binding conformation of BCR-ABL and that mutations even outside the kinase domain can lead to enhanced autophosphorylation of the kinase, thereby stabilizing the active conformation that resists imatinib binding. So far, 25 different substitutions of 21 amino acid residues of BCR-ABL have been detected in CML patients. In addition, it has been recently illustrated that mutations preexist the onset of treatment and that some confer a more aggressive disease phenotype. Finally it has been shown that molecular remission is almost never reached through Imatinib therapy. The most common mechanism of relapse for CML patients treated with Imatinib is the appearance of point mutations in the BCR-ABL oncogene that confer resistance to this drug. Insights into the emerging problem of resistance should promote the rational development of alternative, synergistic, and potentially curative treatment strategies.