BCR-ABL Transcript Levels Research Articles

Prognostic Significance of Regulatory T-Cells and PD-1 + CD8 T-Cells in Chronic Myeloid Leukemia Patients Treated with Generic Imatinib.

The impact of T-regulatory cells (Tregs), PD-1 + CD8 T-cells, and their dynamics during treatment with imatinib mesylate remains poorly understood in patients with chronic myeloid leukemia (CML). We conducted a prospective study on newly diagnosed, treatment-naïve adult (> 18years old) patients with CML in the chronic phase (CP) and age- and sex-matched controls. Peripheral blood samples were collected at diagnosis and after three months of imatinib therapy to assess Tregs and PD-1 + CD8 T-cell levels using flow cytometry. The study comprised 57 patients with a median age of 39years, including 27 males (47%). At baseline, the mean percentage of Tregs was significantly higher in CML patients (3.6 ± 0.32%) compared to controls (1.58 ± 0.21%) (p < 0.0001) but decreased significantly after three months of imatinib treatment (1.73 ± 0.35%) (p < 0.0001). Baseline Treg% exhibited positive correlations with Sokal (r = 0.29), Hasford (r = 0.33), EUTOS (r = 0.28), and ELTS (r = 0.31) risk scores (p < 0.05), as well as with the BCR-ABL transcript levels at three months (p = 0.03). Furthermore, the mean baseline percentage of PD-1 + CD8 T-cells was significantly elevated in CML patients (7.66 ± 0.36%) compared to controls (2.65 ± 0.32%) (p < 0.0001) and also decreased after treatment (3.44 ± 0.37%) (p < 0.0001). The baseline percentage of PD-1 + T-cells demonstrated positive correlations with Sokal (r = 0.26), Hasford (r = 0.27), and ELTS (r = 0.41) risk scores (p < 0.05). Our findings reveal a significantly higher proportion of Tregs and PD-1 + CD8 T-cells in patients with CML-CP compared to healthy controls, notably diminished following imatinib treatment. These observations suggest the potential for immunotherapy as a promising approach to managing immune exhaustion in CML patients.

Impact of MDR-1 Gene Polymorphism (rs1128503) on Response to Imatinib or Nilotinib in Iraqi Patients with Chronic Myeloid Leukemia: An Observational Study

Background: There is a significant molecular response to imatinib given at standard doses in individuals with chronic myeloid leukemia (CML) whose ABCB1 polymorphisms are present. Objective: To investigate the impact of the polymorphism in the ABCB1 gene rs1128503 on the effectiveness of nilotinib or imatinib therapy. Methods: From May 2022 until the end of January 2023, the current study was carried out in a single research institution, the National Center of Hematology, Baghdad Teaching Hospital at Medical City, Iraq. 76 people with chronic phase myeloid leukemia (CML-CP), who had previously received a diagnosis using the European Leukemia Net (ELN) criteria, enrolled in the trial. The PCR product was delivered to Macrogen Corporation, Korea, for Sanger sequencing on an automated DNA sequencer, the ABI3730XL. After receiving the results by email, Geneious Prime software was used for analysis. Results: Patients receiving imatinib or nilotinib did not differ significantly in terms of age or gender. In contrast, BCR-ABL1 transcript levels were considerably greater at sampling in patients receiving nilotinib. Different types of the MDR-1 gene rs1128503 genotype were not found in groups that were treated with either imatinib or nilotinib. Conclusions: BCR-ABL1 transcript levels are lower in patients still receiving imatinib than in those receiving nilotinib.

The role of gene expression hypoxia-inducible factor-1a and serum level monocyte chemoattractant protein-1 in the incidence of chronic myeloid leukemia in Iraqi patients

Abstract: BACKGROUND: Chronic myeloid leukemia (CML) is a hematopoietic stem cell malignancy described by a translocation between chromosomes 9 and 22. There are many factors genetic or nongenetic effect on disease progression such as growth factors and transcription factors act as oncogenes or tumor suppressor genes. OBJECTIVES: The purpose of this research was to investigate the role of hypoxia-inducible factor (HIF1A) gene expression with CML, as well as the role of monocyte chemoattractant protein-1 (MCP-1) as a predictive biomarker on disease progression. MATERIALS AND METHODS: The current study consists of three groups: first group includes 50 newly diagnosed CML patients (females 22 and males 28), second group consists of 50 CML patients treated with tyrosine kinase inhibitor (TKI) with a complete molecular response (p210 BCR-ABL transcript levels ≤0.1% IS) (female 25 and male 25), and third group included another 50 apparently healthy volunteers (female 20 and male 30). The patients were admitted from the National Center of Hematology/Mustansiriyah University. All patients are diagnosed according to a complete blood count (CBC), a bone marrow examination, and a BCR-ABL gene test. RESULTS: Reverse transcription-quantitative polymerase chain reaction was applied to assess the expression levels of the HIF-1A gene and serum level of MCP1 by enzyme-linked immunosorbent assay. The results displayed downregulated of the HIF1A gene messenger RNA in CML patients in comparison to the controls group, as well as no statistically significant link was discovered when the fold of expression was correlated with the age and gender of CML patients. CONCLUSION: HIF1-alpha gene has an important role in pathological pathways such as angiogenesis. According to this study, HIF1-alpha gene is not an appropriate prognostic biomarker for detecting the risk of CML as well as MCP1 is thought to be a predictor of CML progression.

Flumatinib for the Treatment of Adult Patients with Resistant or Intolerant Chronic-Phase Chronic Myeloid Leukemia: Results from Real-World Data

Introduction Over the past decades, BCR-ABL1 tyrosine kinase inhibitors (TKIs) as the initial treatment for chronic phase Philadelphia chromosome-positive (Ph+) chronic myeloid leukemia (CML-CP) have dramatically turned CML-CP into a manageable and potentially curable chronic disease. Nonetheless, in spite of the massive improvement in CML treatment over the last years with the introduction of TKIs, some patients (20%-30%) display intrinsic or acquired resistance to treatment during the disease course. Flumatinib Mesylate is a newer and orally available TKI with higher selectivity and potency against BCR-ABL1 kinase versus imatinib. According to the previous data，flumatinib can be an effective first-line treatment for CML-CP. Patients and Methods This study was initiated mainly to observe the safety and efficacy of flumatinib in the treatment of adult patients with resistant or intolerant Chronic-Phase Chronic Myeloid Leukemia, especially in second-line or above treatment in the real world. Efficacy and safety assessments were collected for the intent-to-treat population. Major molecular response (MMR) was defined as BCR-ABL1 transcript level ≤ 0.1% on the International Scale (IS), molecular response (MR4) was defined as BCR-ABL1 transcript level (IS) ≤ 0.01%; MR4.5 was defined as a BCR-ABL1 (IS) transcript level ≤ 0.0032%. DMR was defined as MR 4.0 or MR 4.5. Results Among the 58 evaluable patients with CML-CP, 54% were male, 47% were female. The median age of these patients is 45Y. During the observation period, there were 28 second-line conversion patients (48%), 19 third-line conversion patients (33%), and 11 fourth-line and above patients (19%). Prior therapies included imatinib, dasatinib, nilotinib, olverembatinib, radotinib and ponatinib. All patients converted to treatment of 600mg flumatinib daily. Among the 58 evaluable patients, 20 patients who had been treated with imatinib alone were converted to flumatinib, including 9 cases of IM resistance, 8 cases of IM intolerance and 2 case of personal reasons. During the 1-year follow-up, 52% of patients (n=30) were evaluable for the achievement of MMR. The patients with BCR-ABL1 (IS) &amp;gt; 10% at baseline, 3, 6 and 12 months were 48%, 17%, 23% and 26%, respectively; for patients with BCR-ABL1 (IS) &amp;lt; 0.1% were 26%, 40%, 49% and 52%, respectively; for patients with DMR were 26%, 40%, 49% and 52%, respectively. For imatinib-intolerant or -resistant patients, MMR was 44%. Subgroup analyses showed that the imatinib-intolerant or -resistant patients with BCR-ABL1 (IS) &amp;gt;10% at baseline, 3, 6 and 12 months were 65%, 0%, 10% and 0%, respectively; for patients with BCR-ABL1 (IS) &amp;lt; 0.1% were 10%, 33%, 80% and 44%, respectively; for patients with DMR were 5%, 11%, 30% and 11%, respectively. Meanwhile, 11% of patients could not be detected at molecular level (0.000%). Of the 58 patients, only Grade 1 AEs were reported, including diarrhea, rash and eye edema. Conclusion Flumatinib has good efficacy and safety in the treatment of adult patients with resistant or intolerant Chronic-Phase Chronic Myeloid Leukemia, it will be a good choice for second-line or above treatment for CML-CP In clinical practice.

Treatment-Free Remission Era: BCR-ABL1 mRNA Transcript Level

Background: Early acquisition of a deeper molecular response (DMR) and maintenance of a sustained DMR are prerequisites for implementing treatment-free remission (TFR) in CML patients. Earlier identification of patients who have not reached 24-month DMR and timely intervention is particularly important for patients with a strong desire for TFR. Early molecular response (EMR) of BCR-ABL1 mRNA &amp;lt;10% at 3 months after the initiation of TKI therapy is strongly predictive of a 12-month major molecular response (MMR). Whether the EMR &amp;lt;10% is also a good predictor of the 24-month DMR is unknown. Exploring early predictors of 24-month DMR could help guide clinical treatment decisions and advance the implementation of the TFR plan. Aim: Exploring early predictors of 24-month DMR. Methods: We performed a retrospective analysis of all adult patients with newly diagnosed CML-CP in the Department of Hematology at Guangdong Provincial People's Hospital (Guangzhou, China) between Mar 2009 and May 2019. Patients were monitored with BCR-ABL1 mRNA quantitative RT-PCR monthly for the first 3 months of TKI treatment, then every 3 months for a minimum of 2 years, and then every 3 to 6 months. Results: A total of 314 patients with complete medical recorders and routinely monitoring BCR-ABL1 mRNA transcript data of each molecular response milestone were enrolled. Patients' characteristics are summarized in Table 1. The median follow-up time was 54 months (14 to 146 months). The 5-year cumulative rate of MMR, MR 4 and MR 4.5 with TKI treatment were 80%, 48.1%, and 38.4%, respectively. The results of the ROC analysis showed that a 3-month BCR-ABL1 mRNA transcript level of 4.94% correlated well with the 24-month DMR. The sensitivity and specificity of its predictive function were 82.8% (95% CI, 73.6-89.8) and 66.97% (95% CI, 60.3-73.1), respectively. So, we adopted BCR-ABL1 mRNA transcript level ≤4.94% at 3 months as the optimal threshold for predicting 24-month DMR. To reveal the cumulative incidence (CI) of 12-month MMR, 24-month MR 4 and MR 4.5 at different thresholds of BCR-ABL1 mRNA transcript levels at 3 months. Patients were divided into 3 groups according to the BCR-ABL1 mRNA transcript levels, group I &amp;lt;5% (n=150, 47.7%), group II 5% to 10% (n=36, 11.5%), group III &amp;gt;10% (n=128, 40.8%). Patients with BCR-ABL1 mRNA transcript levels &amp;lt;5% at 3 months after TKI initiation are more likely to achieve DMR than the other two groups and take less time to achieve DMR. Patients of Group I with 12-month MMR and 24-month MR 4 were significantly higher than the other two groups, with 66.7% vs 30.6% or 8.6% and 50% vs 16.1% or 7% (P&amp;lt;0.001), respectively. And group II was compared with group III. The cumulative incidence of MMR, MR 4 and MR 4.5 was also significantly higher in Group I than in the other two groups (Fig.1). The survival outcome of patients with BCR-ABL1 transcript levels &amp;lt;5% at 3 months had significantly superior compared with those with BCR-ABL1 transcript levels ≥5%: the 5-year EFS， PFS and OS were 88.6% vs 86.4% (P=0.037), 100% vs 95.7% (P=0.011) and 100% vs 95% (P=0.014)， respectively (Fig. 1). Conclusion: BCR-ABL1 mRNA transcript levels &amp;lt;5% at 3 months is a new landmark EMR (EMR &amp;lt;5%) which can predict 24-month DMR for patients with TKI treatment. EMR &amp;lt;5% may be used to guide the clinical timely switching of TKI or treatment and facilitate the implementation of TFR.

Flumatinib Versus Nilotinib for Newly Diagnosed Chronic Phase Chronic Myeloid Leukemia

Introduction Tyrosine kinase inhibitors (TKIs) have considerably improved the long-term clinical outcomes in patients with chronic phase chronic myeloid leukemia (CML-CP). Most of these patients receive 1 st generation TKI imatinib as first-line therapy; however, an increasing number of patients are now receiving 2 nd generation TKIs as first-line therapy, because of the more potent BCR-ABL1 inhibition with proven efficacy in patients resistant or intolerant to imatinib. Flumatinib is a novel 2 nd generation BCR-ABL1 TKI with promising efficacy and manageable safety in newly diagnosed CML-CP. Compared to imatinib, patients treated with flumatinib have achieved significantly higher rates of 12-month major molecular response (MMR) and complete cytogenetic response were observed in patients with CML-CP and that too within a shorter time duration. Though there have been many studies comparing 2 nd generation TKIs vs imatinib in CML-CP, studies comparing clinical outcomes between different 2 nd generation TKIs are scarce. Here, we report the real-world effectiveness and safety of flumatinib and nilotinib in patients with newly diagnosed CML-CP. Methods In this study, adult patients (≥18 years old) with newly diagnosed Philadelphia chromosome-positive (Ph+) CML-CP who received either 300 mg nilotinib twice daily or 600 mg flumatinib once daily, were included, with a follow-up duration of roughly 3 years (NCT04739826). The primary endpoint was the rate of MMR at 12 months as defined by European LeukemiaNet 2020 recommendations (BCR-ABL1 transcript level ≤0.1% in peripheral blood on RT-PCR assay on International Scale [IS]).The secondary endpoints were the rate of early molecular response (EMR) at 3 months (BCR-ABL1 IS ≤10%), the rate of molecular response at 6 months (BCR-ABL1 IS ≤ 1%) and safety (adverse events [AEs] reports in accordance to Common Terminology Criteria for Adverse Events, version 4.03). Results A total of 446 patients were enrolled in the study between November 2020 and August 2022, of which 150 and 296 patients were enrolled in nilotinib and flumatinib groups, respectively. The baseline characteristics were comparable between the two groups (Table 1). No significant difference in the rate of MMR was observed at 12 months between nilotinib and flumatinib (78% vs 80%; P=0.68) . Similarly, no significant difference was observed in the rate of EMR at 3 months (85% vs 89%; P=0.26) and the rate of optimal molecular response at 6 months (93% vs 92%; P=0.70; BCR-ABL1 is ≤1%) between the two groups. The overall safety profile was similar between the two groups. However, hyperbilirubinemia (47% vs 7%), increased ALT (33% vs 12%), increased AST (24% vs 9%), rash (30% vs 18%) and anemia (19% vs 10%) were more frequent in nilotinib group than flumatinib group, whereas diarrhea was lower in nilotinib than flumatinib (2.7% vs 8.8%). The incidence rate of grade 3-4 AEs were reported to be 13% in nilotinib group and 10% in flumatinib group. The safety of flumatinib was more favorable compared to nilotinib in terms of hepatic toxicities, skin toxicities, etc. (Figure 1). Conclusion The efficacy of flumatinib is comparable to nilotinib in Chinese patients with newly diagnosed Ph+ CML-CP. The overall incidences of grade 3-4 AEs were also accessible for the two drugs, nevertheless, a few AEs inclusively hepatic toxicity, anemia and skin toxicity were remarkably lower with flumatinib intervention.

Evaluating Effectiveness and Safety of Flumatinib for Chronic Phase Chronic Myeloid Leukemia in (CML-CP) without Optimal Response (Warning, Failure) to Imatinib or/and Dasatinib

Introduction Flumatinib is a novel second-generation BCR-ABL1 targeted kinase inhibitors (TKI) with better efficacy and safety than first generation TKIs in first-line treatment of chronic myeloid leukemia in chronic phase (CML-CP). In the previous phase III study, newly diagnosed CML-CP patients receiving flumatinib achieved higher treatment responses and safety than imatinib. When it comes to the patients not achieving the optimal response to TKIs, flumatinib is potentially a better option, nonetheless the robust evidence is unavailable. This study reports the effectiveness and safety of switching to flumatinib in patients who have not achieved the optimal molecular response to imatinib or/and dasatinib. Methods This prospective, multicentre study enrolled Philadelphia Chromosome-Positive (Ph+) CML-CP patients aged ≥18 years and who failed to achieve the optimal response with imatinib or/and dasatinib between March 2021 to October 2022. All patients were treated with flumatinib 600 mg once a day and followed up to 24 months. The primary endpoint of the study was rate of major molecular response (MMR) at 12 months as defined by European LeukemiaNet 2020 recommendations (BCR-ABL1 transcript level ≤0.1% in peripheral blood on RT-PCR assay on International Scale [IS]) and safety was the secondary endpoint assessed with CTCAE 4.03 version. In addition, the optimal molecular response in either the warning or failure patients was evaluated at 3, 6 and 12 months respectively, after switching to flumatinib, and the difference in effectiveness was also analyzed from the available mutation subtypes. Results Overall, 94 patients with Ph+ CML-CP were included in the study. The median (range) age of the patients were 53 (19.0-84.0) years old and 61.7% of the patients were males. A total of 38 (40.4%) patients reported warning response from the previous TKIs whereas 56 (59.6%) of patients reported treatment failure to the previous TKIs. Seventy-seven (81.9%) patients have been treated with one TKI, either imatinib or dasatinib, and 17 (18.1%) have been treated with both prior to the study. Overall, 25 (54%) patients achieved MMR at 12-months follow-up compared to the baseline (Figure 1). The rates of optimal molecular response at 3- and 6-months were also improved compared to the baseline. The optimal molecular response was 76(88%) at 3 months, and 52(73%) at 6 months. Subgroup analysis with previous response to TKIs revealed that flumatinib improved the rates of optimal molecular response in both warning and failure groups. Switching to flumatinib from imatinib or/and dasatinib have been reported with an enhanced optimal molecular response in patients who experienced warning compared with those who had treatment failure after the TKIs with 38 (100%) vs 38 (79%), 29 (91%) vs 23 (59%) and 15 (68%) vs 10 (42%) at 3-, 6- and 12-months respectively (Figure 2). Similarly, the rates of optimal molecular response were improved in patients without mutations compared to those having mutations, 65 (90%) vs 9 (75%) at 3 months, 46 (77%) vs 5 (56%) at 6 months and 23 (59%) vs 1 (20%) at 12 months respectively. The most common adverse events (AEs) were diarrhea in 17 (18%), rash in 11 (12%), bloating in 11 (12%), and thrombocytopenia in 11 (12%) patients. Common hematological AEs of grade 3/4 were thrombocytopenia in 7 (7%), anemia in 3 (3%) and leucopenia in 1 (1%) patients. Conclusion For Ph+ CML-CP patients without the optimal molecular response in previous imatinib or/and dasatinib, flumatinib is a better alternative to the existing treatments. In addition, if the patients were switched to flumatinib earlier, the optimal response was achieved faster. The grade 3/4 AEs were mainly hematologically related, whereas the gastrointestinal events were mostly of grade 1-2.

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

Cytogenetic and Molecular Remission in Chronic Myeloid Leukemia in Togo

The availability of tyrosine kinase inhibitors (TKIs) in Togo through the GIPAP program has revolutionized the management of chronic myeloid leukemia and increased patient life expectancy. However, diagnosis and molecular monitoring of therapeutic efficacy remain a real challenge due to the inaccessibility of cytogenetic and molecular biology tools. We’ve conducted, a cross-sectional, descriptive study that ran from December 21, 2022, to January 20, 2023, with the aim to evaluate the cytogenetic and molecular remission in CML patients followed at the CHU Campus de Lomé in Togo. Patients diagnosed with chronic-phase CML who had been treated for at least three months with imatinib or dasatinib and had achieved complete hematological remission were included. Dosage of BCR-ABL transcript levels was performed by RQ-PCR in Seattle, USA, using Dried Blood Spot. The transcript detection limit was 0.003% i.e., MR4. A total of 38 patients were included, 68.4% of them were treated with imatinib and 31.6% with dasatinib. In terms of remission, 28.9% had not achieve a partial cytogenetic remission while 15.8% of patients had achieved a MR4 remission and 7.9% a major molecular remission. Major molecular remission was achieved at a mean follow-up time of 95 months for patients taking imatinib and 22 months for those taking dasatinib. Patients in MR4 were on imatinib after a mean of 68 months. All in one, our study showed a high rate of treatment failure. Better access to cytogenetic and molecular biology tools is needed to improve management.

CYP Inhibition and Low-Dose Dasatinib for Chronic Myeloid Leukemia: Preliminary Results of a Promising, Cost-Effective Treatment Option

Introduction The standard treatment for newly diagnosed (ND)-CML is tyrosine kinase inhibitors (TKIs) such as dasatinib. However, the cost of treatment with these drugs can be prohibitively high. The CYP inhibition strategy involves intentionally inhibiting a specific enzyme, in this case CYP3A4, to increase plasma concentration of dasatinib and reduce the required dose from 100mg to 25mg daily. Patients and methods Five consecutive patients older than 18 years, with ND-CML in chronic phase and Eastern Cooperative Oncology Group (ECOG) of 0-2.The diagnosis and classification of CML followed the ESMO guidelines. After diagnostic confirmation, patients continuously received half pill of dasatinib (25mg orally daily) and a strong CYP3A4 inhibitor (ketoconazole, 200mg orally twice daily). Patients were monitored weekly during the first month and then monthly after that. The response to treatment was established according to the ESMO guidelines. Statistical analysis We examined the distribution of variables using the Shapiro-Wilk test, and descriptive analyses were conducted for demographic and clinical characteristics. The proportion of hematological and non-hematological side effects and the proportion of hematological response were obtained. To demonstrate the effect of dasatinib on hematological cells, we constructed a line plot showing the values of hemoglobin, leukocytes, and platelets in each visit. We compared basal hemoglobin, leukocytes, and platelets vs. follow-up counts at each visit with the Kruskal-Wallis test Results The median age of the patients was 42 years. All patients had a median ECOG score of 0. Three patients (60%) presented with thrombocytosis, three (60%) with splenomegaly, and two patients (40%) had B symptoms. Basal median (range) hemoglobin, leukocytes, and platelets counts were 9.9 g/dL , 272×10 9/L and 451×10 9/L, respectively. Three patients (60%) had low-risk CML, and two patients (40%) had high-risk disease, with a median EUTOS score of 71 points. Dasatinib treatment was initiated within a median of 9 days from diagnosis. In the first 28 days of treatment, median leukocytes and platelets were significantly reduced compared to baseline, with a reduction in leukocytes of 93.7% (125×10 9/L vs. 7.9×10 9/L, p=0.005) and in platelets of 64.6% (407×10 9/L, vs. 144×10 9/L, p=0.027). Hemoglobin levels significantly increased by the second month of treatment, with an increase of 26.4% from baseline (10.2 g/dL vs. 12.9 g/dL, p=0.023). All patients (100%) achieved major hematological response within a median of 22 days. Patient number 1 achieved the 3-month and 6-month treatment goals with 6.4% and &amp;lt;1% reduction in BCR-ABL transcript levels, respectively. After 3 months of treatment, 60% of patients achieved the BCR/ABL1 transcript level on the IS &amp;lt;10%, which is the optimal response according to guidelines, in the rest of the patients the time of evaluation has not been reached. Mild and self-limited adverse events were reported in 40% of patients at some point in their treatment. Non-hematological toxicity occurred in one patient (20%) with nausea and galactorrhea due to ketoconazole. Hematological toxicity occurred in (20%) of patients; the platelet count returned to normal after suspending ketoconazole for one week. No serious adverse events were reported. Conclusion Apart from this preliminary study, there is currently no evidence supporting the intentional use of CYP inhibition to reduce the dosage and cost of dasatinib for patients with ND-CML. Dasatinib is primarily metabolized using the CYP3A4 isoenzyme, and studies have shown that ketoconazole, an accessible antifungal, can strongly inhibit CYP3A4, increase dasatinib's plasma concentration and AUC by 5-fold and 385%, respectively, and allow for a reduction in dosage while maintaining therapeutic efficacy. The CYP inhibition strategy can decrease the cost of dasatinib to a point where it is cheaper than full-dose imatinib -the cheapest TKI- and represent a treatment option for patients who cannot afford full-dose dasatinib in low income countries. The CYP inhibition strategy can be of added value to the lower effective dose concept and give rise to ultra-low-dose schemes. This strategy could significantly increase dasatinib accessibility in many countries by reducing costs from $1,343.7 to $40.3-$100.8 monthly

Safety and efficacy of Vitamin D3 supplementation with Imatinib in Chronic Phase- Chronic Myeloid Leukaemia: an Exploratory Randomized Controlled Trial

ObjectivesThe study aimed to compare early molecular response (EMR) rates at 3 months of imatinib therapy with and without vitamin D3 supplementation in patients newly diagnosed with chronic-phase chronic myeloid...

The role of miRNA- 96 and miRNA-150 between different BCR-ABL p210 transcript levels and between different levels of imatinib optimal response in CML patients

BackgroundDysregulation of miRNA expression patterns is one of the several effects developments of cancer. MiRNA has been found to express abnormally in hematological neoplasia such as chronic myeloid leukemia and solid malignancies. Resistance and the degree of response following tyrosine kinase inhibitor (TKI (treatment are correlated with miRNA expression. Hence this study has evaluated the correlation between miRNA- 96 and miRNA-150 with different p210 BCR-ABL transcript levels and the role of miRNA- 96 and miRNA-150 at different levels of imatinib optimal response in CML patients. MethodThis study is based on 60 CML patients divided into two groups based on response to imatinib therapy. 30 samples have the optimal molecular response of CML patients. The other 30 samples that have failed molecular response CML patients, which were compared to 30 samples of healthy volunteers as control by depending on the results of CBC film and PCR. BCR-ABL 210 transcript, which was used in this study, is obtained from the patient's file. ResultsThe results based on the comparison of transcript levels showed that there was a significant difference between the positive response and failed response of CML patients (P ≤ 0.0001). The result of miRNA-96 showed that there was no noteworthy difference within both CML patients (P ≥ 0.5030), while miRNA-150 results exhibited a high significant difference (P ≤ 0.0001). The miRNA-96 and miRNA-150 expression levels in all responses of CML patients demonstrated a highly significant difference with P = 0.0134 and P = 0.0002, respectively. The cut-off value of response against failure response of miRNA-96 and miRNA-150 with P value of 1.691 and 1.784, respectively with high sensitivity is a diagnostic value of the difference between the response and failure response. Conclusionmodulating gene expression with different of miRNAs expression has an impact on drug-gene interactions, with consequences for cell growth and death. The gene expression that shows the different level miRNAs (miRNA- 96 and miRNA-150) among of CML patients of imatinib therapy exhibited high expression in response patients than that of the failure response of patients. The gene expression level of miRNA- 96 and miRNA-150 was differed between through different response CML patients.

Challenges of the Treatment with Tyrosine Kinase Inhibitors in Chronic Myeloid Leukemia – Case Presentation

We present the case of a 33-year-old male patient diagnosed with chronic phase chronic myeloid leukemia in June 2008. According to treatment protocols enforced at that time, the patient started oral treatment with imatinib 400 mg/day, reaching a major molecular response (MMR) in 18- month time. The molecular response improved over time, with an undetectable BCR-ABL1 transcript level after 36 -48 months of treatment. However, the profound molecular response did not last, requiring a switch to the second line of therapy after 75 months of imatinib. Taking nilotinib 400 mg x2/day, the patient achieved a major molecular response in 12 months, and after 18 months of treatment, the level of BCR-ABL1 became undetectable. However, two vasooclusive events occurred in 2018 – a transient left parietal ischemic stroke and a left femoral artery occlusion – and by ESMO 2017 recommendations, nilotinib treatment was interrupted. The treatment-free remission decision was made with monthly monitoring of the BCR-ABL1 transcript level, but since the 4th month of monitoring, the deep molecular response disappeared. Administration of dasatinib, the third tyrosine kinase inhibitor, resulted in a deep molecular response which currently lasted until now, during the 58 months of treatment. The presented case represents the evolution of the concept of treatment in this haemato-oncological disease during the last decade.

Severe persistent marrow aplasia in chronic myeloid leukemia (CML): An unusual complication of imatinib.

Imatinib has changed the treatment of chronic myeloid leukemia (CML) drastically since 15 years. It is usually well tolerated, but severe persistent marrow aplasia is an unusual complication of imatinib while using it in CML. The aim of this study is to describe our experience confronting this rare side effect and review the available data worldwide. It was a retrospective analysis conducted at a center from February 2002 to February 2015. This study was endorsed by our Institutional Review Board (IRB) and written consent was taken from all patients. Patients diagnosed as Philadelphia (Ph) chromosome-positive CML either in chronic phase (CP), accelerated phase (AP), or blastic crisis (BC) were included. There were a total of 1,576 patients with CML treated with imatinib during this period. Karyotyping and quantitative reverse transcriptase polymerase chain reaction (RT-qPCR) were done at the time of pancytopenia for all patients. In total, 11 (males = 5, females = 6) patients met our inclusion criteria from 1,576 patients of CML. The median age was 58 years (range 32-76). Out of 11 patients 8, 2, and 1 patients were in CP, AP, and BC phases, respectively. The median time of administration of imatinib was 3.3 months (range 1.5-6). The average time of marrow recovery was 10.4 months (range 5-15). Two patients expired (one from septicemia and the other from intracranial hemorrhage). BCR-ABL transcripts level by RT-PCR revealed the existence of the disease in all patients. Imatinib is a very well-tolerated tyrosine kinase inhibitor (TKI), but is associated with persistent myelosuppression when used in older age, advanced phase of the disease, and treated previously. After confirming persistent marrow aplasia, the treatment is mainly supportive. It is striking that the disease is still persistent, which is confirmed by RT-PCR. There is no consensus regarding recalling imatinib at lower doses or the use of second-generation TKI (nilotinib, dasatinib) in these patients.

Activation-Induced Cytidine Deaminase Expression in Patients with Chronic Myeloid Leukemia

Objective: The findings on chronic myeloid leukemia (CML) patients suggest that clonal tumoral cells tend to have additional mutations besides the formation of the BCR-ABL fusion gene. Previous studies have demonstrated abnormal activation-induced cytidine deaminase (AID) expression in various types of cancer, showing AID transcript levels to be elevated in the CML blast phase. The study aimed to investigate the AID gene expression levels in CML and to investigate the etiopathogenic role of AID, which is not yet fully understood. Materials and Methods: This study analyzed the AID transcript levels of 80 CML patients and 50 controls using real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR). Results: The study found the AID transcript levels to be significantly elevated (p &lt; 0.001) in the CML patients compared to the control group, with no significance in AID transcript levels with regard to the patients’ age, gender, clinical characteristics, or laboratory findings. No correlation was found between the AID and BCR-ABL transcript levels, while a positive correlation was present between AID transcript levels and presence of polymorphonuclear leukocytes (PMNL; r = 0.320, p = 0.021). No significant relationship occurred in AID transcription levels with the tyrosine-kinase-inhibitor (TKI) resistant mutation profile or cytogenetic response during TKI therapy. Conclusion: This study found AID expression levels to be significantly elevated in CML patients and AID to be able to contribute to the etiopathogenesis of CML

The role of miRNA -181C between different BCR-ABL p210 transcript levels and between different levels of imatinib optimal response in CML patients

BackgroundThe development of cancer is just one of the many effects of dysregulation of miRNA expression patterns, miRNA have been found to express abnormally in hematological neoplasia such as chronic myeloid leukemia and solid malignancies. Resistance and the degree of response following TKI treatment are correlated with miRNA expression. Hence, in this study we tried to study the relationship of miRNA- 181c between different p210 BCR-ABL transcript levels and the role miRNA-181c between different levels of imatinib optimal response in CML. MethodOur study included sixty CML patients they were divided into two groups based on response to imatinib therapy, thirty samples optimal molecular response of CML patients and thirty samples of failure molecular response CML patients. Thirty samples of apparently healthy volunteers were included and evaluated as control. ResultsAccording the P210 BCR-ABL% results there was a significant difference (P ≤ 0.0001), between the responder and the failure response CML patients, assessed the expression of the level miRNA-181c the result showed high significant difference between both CML patients groups (P = 0.0012). Assessed the expression of the level miRNA-181c in different responses and failure response of CML patients, there was a significant difference of miRNA-181c level among different responses groups and failure response of CML patients (P = 0.0044). A cutoff value of response vs. failure response (7.24) with high sensitivity can be of diagnostic value to differentiate between response and failure response. ConclusionChanging gene expression with different amounts of miRNAs has an impact on drug-gene interactions, with consequences for cell growth and death. Gene expression different level miRNA-181c among of CML patients of imatinib therapy were high expression in response patients than failure response patients. The gene expression level of miRNA-181c differs between through different response CML patients.

Comparison of Generic Dasatinib Versus Imatinib in Newly Diagnosed Chronic Phase Chronic Myeloid Leukemia with Reference to Early Molecular Response: Results from a Single-Center, Randomized Controlled Study from India

Background: Chronic myeloid leukemia (CML) is the commonest leukemia in adult population in India. The advent of tyrosine kinase inhibitors (TKI) targeting BCR-ABL1 fusion transcript in CML has dramatically improved survival of CML patients. Generic formulations of imatinib mesylate have been the mainstay of TKI therapy in Indian CML patients for more than a decade, due to prohibitive costs of 2nd generation TKIs and poor socio-economic status of majority of patients. However, with the availability of generic dasatinib in India since March 2021, the cost of dasatinib therapy has become comparable to that of generic imatinib treatment, thereby enabling more extensive use of dasatinib as first-line TKI therapy in CML patients in India. Achievement of early molecular response (EMR) after 3 months of first-line TKI therapy, defined as blood BCR-ABL1 transcript level ≤ 10% [international scale (IS)], has emerged as an important predictor of favorable long-term outcome in CML-CP. There is scarcity of data on efficacy & safety of generic formulations of dasatinib vis-à-vis generic imatinib in CML-CP patients in India, which the present study has attempted to explore at a tertiary care hospital in India. Objectives: The objectives of the study were to compare early molecular response (EMR) [defined as BCR-ABL1 transcript level ≤ 10%, I.S.] at 3 months of therapy with generic dasatinib versus generic imatinib in newly diagnosed CML-CP patients and to compare treatment-related adverse effects in the two groups. Methods: This randomized controlled study enrolled newly diagnosed CML-CP patients after obtaining institutional ethics committee approval & informed consent. Inclusion Criteria:Newly diagnosed patients with chronic phase CML.Age ≥ 12 years. Exclusion Criteria:Patients with de novo accelerated phase or blast phase CML.Pregnancy & lactation.Patients with pre-existing pleural effusion, grade ≥ 3 lung disease, or pulmonary arterial hypertension.Patients with angina, or grade ≥ 3 cardiac disease [as defined by the New York Heart Association (NYHA) criteria] at diagnosis.Patients with prolonged QTc interval (> 480 msec) at baseline. The EUTOS long-term survival (ELTS) risk score was calculated at diagnosis. Patients were randomized to one of the two following treatment groups: Group A: Dasatinib 100 mg p.o. once daily (60 mg/m2/day for age <18 years). Group B: Imatinib 400 mg p.o. once daily (340 mg/m2/day for age < 18 years). Follow up & monitoring of patients was done every 2 weekly till completion of 3 months of TKI therapy, followed by assessment of hematological response & molecular response as per standard criteria. Results: A total of 61 consecutive CML patients were screened between June 2021 and March 2022, out of which 54 patients with confirmed diagnosis of CML-CP were enrolled in the study and were randomized to receive generic dasatinib or generic imatinib as first-line therapy and were followed up for 3 months for EMR and complete hematological response (CHR). Four patients were lost to follow up and data was analyzed for 50 patients for whom EMR results at 3 months was available. Out of these 50 patients, 24 patients received dasatinib & 26 patients received imatinib. The median age of patients was 33 years (range 18-64 years), with male: female ratio of 1.3: 1. Achievement of CHR was documented in 96% of patients in both dasatinib & imatinib treatment arms. EMR at 3 months was achieved in overall 72% patients in study [19/24 patients (79%) in dasatinib arm & 17/26 patients (65%) in imatinib arm]. However, the difference was not statistically significant (p = 0.27). Notably, EMR rates in ELTS intermediate-risk group was 86% in dasatinib arm versus 42% in imatinib arm, and EMR rates in ELTS high-risk group was 82% in dasatinib arm versus 57% in imatinib arm (p = 0.33). The incidence of grade 3-4 adverse events was not significantly different in the two treatment groups. The patient characteristics & treatment results are summarized in Table 1 & Figure 1. Conclusion: The results of the present study suggested that generic formulations of dasatinib were well-tolerated and were associated with improved early molecular response rates compared to generic imatinib in CML-CP patients in India. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

First-in-Human Study of Elvn-001, a Highly Selective BCR::ABL1 Tyrosine Kinase Inhibitor, in Patients with Chronic Myeloid Leukemia Who Failed Previous Tyrosine Kinase Inhibitor Therapies

Background: Despite the benefits BCR::ABL1 tyrosine kinase inhibitors (TKIs) have provided altering the natural history of chronic myeloid leukemia (CML), resistance/lack of response and intolerability occurs. ELVN-001 is a highly selective small molecule active site inhibitor of ABL1 that does not significantly inhibit the receptor tyrosine kinases PDGFR, KIT, VEGFR2 or the Src-family (eg SRC, LCK, LYN, FYN). In vitro data also supports ELVN-001 targeting the most common CML mutation, T315I and not being a substrate for drug efflux transporters such as BCRP, which may contribute to resistance or sensitivity to other TKIs. Non-clinical data suggests ELVN-001 has a favorable absorption, distribution, metabolism, elimination and a pharmacokinetic (PK) profile supporting once daily (QD) dosing, low risk of QTc prolongation, and potential to avoid drug-drug interactions, particularly CYP-mediated. This first-in-human (FIH) study will evaluate the safety, tolerability, PK and preliminary anti-CML activity of ELVN-001 in patients (pts) with chronic (CP) or accelerated phase CML with and without T315I mutations. Objectives: The primary objectives are to determine the recommended doses for expansion (RDE) and to evaluate the safety and tolerability of ELVN-001. Secondary objectives are to assess the PK profile and preliminary efficacy. Design: A phase 1 open-label, multi-center, dose escalation and expansion study. Eligible pts are adults with CP and AP CML who are intolerant or have failed (as per ELN 2020 Recommendations) available TKIs known to be active for treatment of their CML. Other key eligibility criteria are Eastern Cooperative Oncology Group performance status 0-2, adequate bone marrow, renal and liver function, and resolved adverse effects of prior therapy. Prior marrow transplant is allowed. CML with point mutations E255, Y253, G250, F317 or Q252 are excluded. Successive cohorts will receive escalating doses of ELVN-001 starting at 10 mg QD. Dosing will be continuous in 28-day cycles until treatment failure, disease progression or unacceptable toxicity. A standard 3+3 dose escalation will be used, with PK/pharmacodynamic modeling to identify the RDEs, assuming toxicity is not dose limiting. Safety and efficacy of ELVN-001 will be further explored in CP-CML without T315I mutations and a cohort of T315I mutated CP-CML. Mutational analyses by Sanger and NGS will be conducted at baseline and end of treatment. Main Outcomes: Primary endpoints are dose limiting toxicities, adverse events, laboratory and ECG abnormalities. Secondary endpoints are PK parameters, response based on BCR-ABL transcript levels by quantitative PCR and hematology. Conclusions: This FIH study will evaluate dosing, safety, tolerability, PK profile and preliminary efficacy of ELVN-001 in CP-CML with and without T315I mutation. Study sponsor: Enliven Therapeutics. NCT05304377 ELVN-001-101 Schema: Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

CLINICAL AND MOLECULAR REPORT OF A RARE RAM POSITIVE NON-DOWN SYNDROME INFANT CBFA2T3-GLIS2 NEGATIVE, PRESENTING THE DRIVER P210-BCR-ABL1

Pediatric Acute Megakaryoblastic Leukemia (AMKL) comprises 4%‒15% of Acute Myeloid Leukemia (AML) cases. Down Syndrome (DS)-AMKL usually displays a favorable outcome, whereas the prognosis of non-DS-AMKL is generally poor. Here we present the clinical and genomic data of a rare non-DS-AMKL infant with p210-BCR-ABL1 fusion, co-occurring with a high-risk WT1 mutation. The baby was RAM positive and CBFA2T3-GLIS2 negative, showing refractoriness to treatment. A 1-year-old girl was referred to the Hospital with a history of fever and motor developmental delay for four months. On admission, she presented ecchymosis, swelling, and organomegaly (spleen and liver). The WBC count was 26.5 × 10 3 /μL, hemoglobin level was 7.6 g/dL, platelet count was 25 × 10 3 /μL, and LDH was 2.887. At diagnosis, she showed bilateral myeloid sarcoma. Morphological analysis of the Bone Marrow (BM) showed clustered cytoplasmic blebs. Flow cytometry analysis revealed 83% of blast cells and a profile compatible with AMKL and RAM phenotype. The patient was treated under the high-risk AML-BFM-2004. Imatinib was incorporated into the treatment after BCR-ABL1 detection. However, minimal residual disease remained positive throughout the treatment, making BM transplantation unfeasible. Disease refractoriness was persistent even with the administration of Dasatinib, FLAG-IDA and Venetoclax. The patient died one year after diagnosis due to sepsis during BM aplasia. We performed G-banding, FISH, and Multiplex RT-PCR experiments. The molecular response was assessed by absolute quantification via RT-qPCR assays. Sanger sequencing and NGS were performed on a targeted approach. The karyotype was 46,XX,t(9;22)(q21;q34). We observed polyploidy (3‒20N). FISH in polyploid Nuclei (8N) showed four BCR-ABL1 fusion signals. In diploid metaphases, we observed two BCR-ABL1 signals. Multiplex RT-PCR detected the p210- BCR - ABL1 . RT-qPCR monitoring detected persistent high levels of BCR-ABL1 transcripts associated with disease refractoriness. Sanger sequencing showed no GATA1 mutation. NGS revealed a missense WT1 pathogenic mutation, and CBFA2T3-GLIS2 was not present. RAM phenotype is characterized by overexpression of CD56 and under-expression of CD38, CD45, and HLA-DR. This phenotype is characteristic of children, usually associated with AML-M7 (38%) and intermediate-risk cytogenetics not associated with prognostic subgroups. RAM is related to a poor prognosis with high MRD and induction failure rates compared to non-RAM patients. This phenotype is associated with the CBFA2T3-GLIS2 fusion, which is related to extramedullary involvement, a particular blast morphology, and a worse outcome as compared to fusion-negative AML pediatric patients, including a high frequency of disease refractoriness and relapse. NGS studies did not show CBFA2T3-GLIS2 in our patient. Thus, our results indicate that RAM+ associated with the driver p210-BCR-ABL1, even with specific targeted therapy, may lead to treatment resistance regardless of CBFA2T3-GLIS2+. Here we highlight for the first time the presence of p210-BCR-ABL1 associated with RAM phenotype in the absence of CBFA2T3-GLIS2 and disease refractoriness in a non-DS-AMKL infant.

Analysis of early molecular response at 3 months in predicting overall response in newly diagnosed patients with chronic myeloid leukemia on imatinib

Objectives: This study aimed to study the correlation between Breakpoint Cluster Region- ABelson Leukemia virus 1 transcript levels at 3 months with the treatment responses at 6 and 12 months in patients on imatinib. Around 30% of patients with chronic myeloid leukemia (CML) might have treatment failure with the first-line tyrosine kinase inhibitors (TKI). Patients with a “warning response” at 3 months can continue therapy with the same TKI while monitoring for disease progression. However, newer pieces of evidence suggest that patients who fail treatment with imatinib do have suboptimal responses in the early time points, and hence, 1st 3-month assessment might be a useful indicator for future treatment failure. Material and Methods: It is a single-center prospective observational study involving 60 treatment-naive consecutive patients with CML-chronic phase who attended Hematology Outpatient Department at IHTM, Kolkata. Treatment responses were assessed by cytogenetics and BCR-ABL1 transcript levels by real-time quantitative polymerase chain reaction at 3 monthly time points. Results: About 51% and 70.2% of the study participants achieved complete cytogenetic response at 6 and 12 months, respectively. About 74% of the participants had achieved early molecular response (EMR) at 3 months. The failure rates of cytogenetic responses were 13% and 20% at 6 and 12 months, respectively. Patients who failed to achieve EMR at 3 months had higher failure rates at 6 months. The major, warning and failure of molecular responses at 6 and 12 months were found to be 15%, 25%, and 9%, and 34%, 39%, and 27%, respectively. The analyses showed that patients who failed to achieve EMR at 3 months are also more likely to have the failure of molecular response at 12 months, with a statistical significance of P &lt; 0.01. Failure of EMR at 3 months also correlated with failure of overall responses (both cytogenetic and molecular at 12 months) with a statistical significance of P = 0.006. When followed up, there was a progression of disease in three including a death in the suboptimal response group. Conclusion: Our patients had inferior treatment responses to imatinib than that observed in the previous studies. The majority have baseline fibrosis of the marrow and splenomegaly at presentation which might contribute to adverse outcomes. The molecular response at 3 months was found to be a consistent and powerful indicator of treatment responses at later time points.