Months Of Tyrosine Kinase Inhibitors Therapy Research Articles

Prognostic and predictive implications of Sokal scoring system in newly diagnosed Chronic Myeloid Leukemia patients

Objective: To assess the predictive utility of the Sokal scoring system for determining disease prognosis in newly diagnosed patients with chronic myeloid leukemia (CML). Methodology: This comparative cross-sectional study was conducted at the Armed Forces Institute of Pathology, Rawalpindi, Pakistan, from September 2021 to September 2022. The study included all newly diagnosed Philadelphia-positive chronic myeloid leukemia (CML) patients. Patients with CML in the accelerated and blast phases, as well as those with atypical CML, were excluded. Gender was considered as a qualitative variable of interest, while platelet count, spleen size, age, and percentage of myeloblasts in the peripheral blood were the quantitative variables of interest. These variables were documented using preformed data sheets, and the prognostic class of each patient was recorded. Follow-up assessments were conducted after 3 months for patients who received the same tyrosine kinase inhibitor (TKI) therapy to avoid bias. Results: A total of 62 patients were included in the study, with a mean age of 46±5 years. According to the Sokal scoring system, 20 (32%) of 62 patients were classified as low-risk, 34 (54.8%) as intermediate-risk, and 8 (12.9%) as high-risk. Conclusion: The routine implication of traditional prognostic scoring systems, such as the Sokal score, is beneficial for stratifying CML patients into different risk groups due to its cost-effectiveness. Regression in Sokal score grades was observed after 3 months of TKI therapy.

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

Lower tumor burden is associated with better cognitive function in patients with chronic phase chronic myeloid leukemia

Cognitive function was assessed in patients with chronic myeloid leukemia in the chronic phase (CML-CP) receiving tyrosine kinase inhibitor (TKI) therapy using the Montreal Cognitive Assessment (MoCA). Cross-sectional assessments of 100 newly diagnosed patients and 584 patients receiving TKI therapy for >1 year showed that 31 (31.0%) and 191 (32.7%) patients had mild cognitive impairment, respectively. In the multivariable analyses, higher percentages of blood blasts were associated with a worse MoCA score at diagnosis [β = −0.29, 95% confidence interval (−0.54, −0.03), p = .027]; deeper molecular response [versus < major molecular response, β = 0.74 (0.07, 1.40), p = .029], better MoCA score on TKI therapy. Increased MoCA scores were observed after 12 months of TKI therapy in 42 patients who were regularly followed up (p = .005). Lower tumor burden is associated with better cognitive function in CML-CP patients both at diagnosis and during TKI therapy.

ABCG2 but Not ABCB1 RNA Levels at Diagnosis and during Treatment Correlates with Response to Imatinib and 2G-Tkis Front-Line Therapy in Chronic Phase CML Patients

Introduction. Overexpression of multidrug resistance proteins ABCB1 and ABCG2 confers resistance to anticancer drugs, including tyrosine kinase inhibitors (TKIs). However, little is known about the significance of ABCB1 and ABCG2 expression during TKI treatment for chronic myeloid leukemia (CML) and possible correlation with response to therapy.Aims. To investigate the role of ABCB1 and ABCG2 expression during the first 12 months of treatment with imatinib and 2G-TKIs for chronic phase CML patients and correlation with molecular response.Methods. We analysed expression of ABCB1 and ABCG2 RNA at diagnosis and after 3, 6 and 12 months of TKI therapy in 20 patients with CML, divided in two groups according to response to treatment. Group A (n=10) comprised patients treated with imatinib that displayed optimal response at 3 months (defined as BCR/ABL <10%), 6 months (BCR/ABL < 1%) and at 12 months (BCR/ABL < 0.1%); group B (n=10) included patients treated with imatinib (n=5) or 2G-TKIs (nilotinib in 3 and dasatinib in 2 cases, respectively) who did not meet the criteria for optimal molecular response at all three timepoint or that switched to alternative treatment after at least the 3rd month. RNA levels were expressed using the 2-ΔΔCt method proposed by Livak and Schmittgen, using ABL as normalizing gene and the expression level of the K562 cell line as calibrator, in order to standardize the results.Results. ABCB1 expression at diagnosis was similar in group A (mean±SD = 0.21±0.22) and in group B (0.15±0.20; p=0.48); similarly, expression during treatment was similar in responding and non-responding patients at 3 (0.82±0.32 vs 0.83±0.41; p=0.66) 6 (0.85±0.22 vs 0.90±0.50; p=0.65) and 12 (1.05±0.24 vs 0.77±0.42; p=0.21) months. Conversely, ABCG2 expression at diagnosis was lower in group A (0.85±0.71) compared to group B (2.83±2.84; p=0.06). RNA levels increased in both groups during treatment, but were always lower in patients with optimal response compared to cases without response or treatment failure: at 3 months (5.12±3.31 vs 49.44±82.70; p=0.13), at 6 months (8.23±8.55 vs 12.71±10.04; p=0.32) and at 12 months (6.05±4.87 vs 13.00±9.93; p=0.05).Considering response to therapy, all patients in group A are still in imatinib with sustained optimal response; all patients in group B receiving imatinib switched to alternative therapy (nilotinib = 2, dasatinib = 1, allogeneic SCT for evolution to blast phase = 1) or died for non-CML causes while not in complete cytogenetic response (n=1), while 3/5 patients receiving 2G-TKI changed therapy (nilotinib to dasatinib = 1, dasatinib to ponatinib = 1, nilotinib to allogeneic SCT for aplasia = 1) and 2/5 patients continued the same drug achieving MMR beyond the 12th month.Discussion. With the limits of a small number of patients, our data suggest that high ABCG2 levels at diagnosis seems to be associated with non-optimal response to imatinib and 2G-TKIs, and an increase in ABCG2 during the first months of treatment is a hallmark of poor response. DisclosuresTiribelli:Novartis: Consultancy, Honoraria; Bristol Myers Squibb: Consultancy, Honoraria; Incyte: Consultancy, Honoraria.

Impact of Molecular Response at Specific Timepoints in Patients with Newly Diagnosed Chronic Myeloid Leukemia Treated with Second Generation Tyrosine Kinase Inhibitors

Impact of Molecular Response at Specific Timepoints in Patients with Newly Diagnosed Chronic Myeloid Leukemia Treated with Second Generation Tyrosine Kinase Inhibitors

Why is it critical to achieve a deep molecular response in chronic myeloid leukemia?

The primary goal of tyrosine kinase inhibitor (TKI) therapy for patients with chronic myeloid leukemia is survival, which is achieved by the vast majority of patients. The initial response to therapy provides a sensitive measure of future clinical outcome. Measurement of BCR-ABL1 transcript levels using real-time quantitative polymerase chain reaction standardized to the international reporting scale is now the principal recommended monitoring strategy. The method is used to assess early milestone responses and provides a guide for therapeutic intervention. When patients successfully traverse the critical first 12 months of TKI therapy, most will head towards another milestone response, deep molecular response (DMR, BCR-ABL1 ≤0.01%). DMR is essential for patients aiming to achieve treatment-free remission and a prerequisite for a trial of TKI discontinuation. The success of discontinuation trials has led to new treatment strategies in order for more patients to reach this milestone response. DMR has been incorporated into endpoints of clinical trials and is considered by some expert groups as the optimal treatment response. But is DMR a stable response and does it provide the ultimate protection against TKI resistance and death? Do we need to increase the sensitivity of detection of BCR-ABL1 to better identify the patients who would likely remain in treatment-free remission after TKI discontinuation? Is it necessary to switch current TKI therapy to a more potent inhibitor if the goal is to achieve DMR? These are issues that I will explore in this review.

ALL-216: Outcomes of Patients with Philadelphia Chromosome-Positive Acute Lymphoblastic Leukemia in Molecular Response at Three Months of Therapy

Context The combination of tyrosine kinase inhibitors (TKI) with intensive chemotherapy improves outcome of patients with Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph-pos ALL), particularly among patients in molecular response within three months of therapy. Objective The aim of this study is to identify prognostic factors for relapse and/or death in patients with Ph-pos ALL after 3 months of therapy. Design Retrospective analysis of patients who enrolled on prospective clinical trials of the combination of hyper-CVAD (HCVAD) with a TKI. Setting MD Anderson Cancer Center. Patients or other participants We analyzed 204 patients with newly diagnosed Ph-pos ALL who were treated with HCVAD with a TKI; imatinib (N=44), dasatinib (N=88), and ponatinib (N=72). Interventions Molecular response was assessed at CR, at 3 months, every 3 months during the first 2 years, and every 3-6 months thereafter. Allogeneic stem cell transplantation was offered at the discretion of patient and treating physician. Ponatinib dose was reduced to 15 mg daily, once CMR is achieved. Main outcome measures Progression -free survival (PFS) was calculated from the date of treatment initiation until date of relapse, or death. Overall survival (OS) was calculated from the time of treatment initiation until death. Results By multivariate analysis for PFS and OS in patients who achieved CMR within 3 months of therapy, ponatinib therapy was the only significant independent factor predicting for progression (P=0.028; hazard ratio [HR], 0.388; 95% confidence interval [CI], 0.166-0.904) and death (P=0.042; HR, 0.379; 95% CI, 0.149-0.966); among patients who did not achieve CMR within 3 months, the achievement of major molecular response was a favorable prognostic factor. Though the number of patients with MMR and without molecular response (i.e., no CMR/MMR) is limited, there was a tendency of improved PFS in patients who received allogeneic stem cell transplant. Conclusions The achievement of CMR within 3 months of therapy is the landmark for long-term survival. Ponatinib maintains CMR, and prevents relapse and death in patients with newly diagnosed Ph-pos ALL. MMR within 3 months was associated with improved survival compared to the lack of MMR within 3 months of TKI therapy.

A phase II multicenter study of stereotactic radiotherapy (SRT) for oligoprogression in metastatic renal cell cancer (mRCC) patients receiving tyrosine kinase inhibitor (TKI) therapy.

5065 Background: SRT is increasingly considered to delay the need to change systemic therapy in metastatic cancer patients who develop oligoprogression. This prospective phase II study evaluated the use of SRT in the setting of mRCC patients who developed oligoprogression while on 1st or 2nd line TKI therapy. Methods: IMDC favourable or intermediate risk mRCC patients (pts) who had previous stability or response on ≥ 3 months of TKI therapy were eligible if they developed radiographic progression of ≤ 5 metastases. The oligoprogressive tumours were treated with SRT while other metastases which were stable or responding to TKI therapy were left alone. TKI therapy was temporarily stopped during SRT, and the same TKI drug then resumed. Endpoints included local control of the irradiated lesions, progression free survival (PFS), overall survival (OS), and cumulative incidence of changing systemic therapy after study entry. Results: 37 pts (median age 63, IMDC favourable 12, intermediate 25) with 57 oligoprogressive tumours were enrolled. 35 pts were on sunitinib and 2 on pazopanib. Median duration of TKI therapy prior to study entry was 18.6 months. 4 pts had IL-2 therapy prior to a 2nd line TKI. 21 pts had a solitary oligoprogressive tumour, while 17 pts had 2-3 oligoprogressive tumours treated with SRT. Median biological effective dose (BED10) was 72 Gy, corresponding to an SRT dose of 40 Gy in 5 fractions. Irradiated tumour sites were the following: 21 lung/pleural, 15 bone, 7 lymph node, 4 adrenal, 4 liver, 3 brain, 2 spleen, and 1 pancreas. At a median followup of 11.6 (1.8-53.5) months the median PFS from study entry was 9.6 months (95%CI 7.4-20.5) with the vast majority of progression occurring outside of the irradiated areas. The 2-year local control of the irradiated tumours was 96%. The 2-year OS from study entry was 77%. The cumulative incidence of changing systemic therapy was 47% at 1 year and 75% at 2 years, with a median time to a change in systemic therapy of 12.6 months. There were no grade 3-5 SRT related toxicities. Conclusions: To our knowledge, this is the first prospective evaluation of the use of SRT for oligoprogressive metastatic cancer. Local control of irradiated oligoprogressive mRCC tumours was high. After delivering SRT, mRCC patients did not need a change in their systemic therapy for a median of 1 year, effectively increasing the PFS of their TKI therapy. This novel approach should be studied in patients with oligoprogression on immunotherapy. Clinical trial information: NCT02019576 .

Characterization of Leukemic Stem Cells Heterogeneity in Chronic Myeloid Leukemia

In chronic myeloid leukemia (CML), a rare subset of leukemic stem cells (LSC) persists in patients responding to conventional tyrosine kinase inhibitor (TKI) therapy. The failure to eradicate these LSCs results in indefinite therapy dependence and a risk of leukemic relapse. However, the conventional LSC compartment (Lin-CD34+CD38-) is highly heterogeneous where only a subpopulation is believed to be functional, TKI-insensitive LSCs. Previously, using single-cell gene expression analysis we characterized the heterogeneity within the LSC population (Lin-CD34+CD38-) in CML patients using a selected panel of 96 primers. Interestingly, by comparing LSC heterogeneity at diagnosis with the heterogeneity following 3 months of TKI therapy we uncovered a therapy-insensitive, quiescent subpopulation, which could be isolated at high-purity using a combination of the surface markers: Lin-CD34+CD38-CD45RA-cKIT-CD26+ (Warfvinge, Geironson, Sommarin et al., 2017). Here, we expand the single-cell analysis of CML LSC populations to include combined immunophenotype-/RNA sequencing analysis (CITE-seq). CITE-seq allows for unbiased, further in-depth transcriptome analysis as wells as immunophenotypic characterization by pre-staining cells with a panel of DNA-barcoded antibodies prior to sequencing. DNA-barcoded antibodies convert the protein expression into readable sequences through unique oligo-conjugates as identifiers. Using CITE-seq with a panel of 44 distinct surface markers designed to immunophenotypically differentiate between stem/progenitors cells and leukemic clones we simultaneously characterize the molecular and immunophenotypic heterogeneity within Lin-CD34+/Lin-CD34+CD38- CML stem/progenitor compartment at diagnosis. Additionally by comparing the LSCs transcriptome from patients with different therapeutic outcome after 12 months of therapy we describe how differences in heterogeneity and the presence of immunophenotypic therapy-insensitive LSCs at diagnosis (Lin-CD34+CD38-CD45RA-cKIT-CD26+) contribute to therapy response. Disclosures Richter: Novartis: Consultancy; Pfizer: Consultancy, Research Funding.

Prospective Evaluation of ABL Kinase Domain Mutational Analysis By Next-Generation-Sequencing in Newly Diagnosed CP CML Patients Undergoing First-Line Treatment with Nilotinib Alone or Nilotinib + Pegylated Interferon-α2a in a Prospective Phase III Trial

Prospective Evaluation of ABL Kinase Domain Mutational Analysis By Next-Generation-Sequencing in Newly Diagnosed CP CML Patients Undergoing First-Line Treatment with Nilotinib Alone or Nilotinib + Pegylated Interferon-α2a in a Prospective Phase III Trial

Effect of high patient out-of-pocket (OOP) cost for oral tyrosine kinase inhibitors (TKIs) on survival in EGFR and ALK positive stage IV non-small cell lung cancer (NSCLC).

3 Background: Patients with EGFR+ or ALK+ NSCLC benefit from oral TKIs, but high patient OOP TKI costs could negatively impact survival by reducing likelihood of continuing TKI therapy. We assessed the association of high OOP TKI costs with overall survival (OS), medication possession ratio (MPR) and duration of TKI therapy (DOT) in patients with metastatic EGFR+ and ALK+ NSCLC. Methods: We identified patients with EGFR+ and ALK+ NSCLC diagnosed between 01/01/2010 and 12/31/2016 in the Washington State SEER registry using natural language processing, followed by manual confirmation of molecular tests. We linked registry records to commercial and Medicare (including part D) claims. Eligible patients had stage IV NSCLC, sensitizing EGFR mutations or ALK+ by FISH, ≥1 pharmacy claims for EGFR or ALK TKIs, ≥3 months survival from TKI start, and ≥12 months of insurance enrollment post diagnosis. We estimated OOP TKI costs by subtracting the amount paid from the amount allowed in pharmacy claims. We categorized patients by quartiles of monthly OOP costs calculated for the first 3 months of TKI therapy (Q1 &lt; Q2 &lt; Q3 &lt; Q4). We used landmark survival analysis with multivariate Cox regression to test the association of monthly OOP costs in the first 3 months of TKIs and OS starting at 3 months of TKI therapy between Q1-Q3 vs Q4. We used t-tests to compare MPR and DOT for the 1st TKI between Q1-3 and Q4. Results: For 106 eligible patients (median age 69; 67% female; 73% White; 35% Medicare, 85% EGFR+), the median monthly OOP TKI costs at 3 months were $0 (Q1); $1,432 (Q2); $1,798 (Q3); $2,888 (Q4). Mean MPR was 1.20 vs. 1.06 (P = 0.02), and median DOT was 8 vs. 4 months (P &lt; 0.01) for Q1-3 vs. Q4. Median OS was 22 vs. 9 months for Q1-3 vs 4. Compared with Q1-3, Q4 patients had a hazard ratio for death of 1.76 (95% CI = 1.05; 2.94; P = 0.03), adjusted for age, sex, insurance, mutation, income, chemotherapy use, and time to TKI start. There were no statistically significant associations comparing Q1 to Q2-4, or Q1-2 to Q3-4. Conclusions: Higher patient OOP TKI costs are associated with lower number of TKI prescriptions, shorter duration of TKI therapy and inferior survival in advanced EGFR+ and ALK+ NSCLC.

CHARACTERIZATION OF THERAPY-INSENSITIVE LSC SUBPOPULATIONS IN CHRONIC MYELOID LEUKEMIA

In chronic myeloid leukemia (CML), a rare subset of leukemic stem cells (LSC) persists in patients responding to conventional tyrosine kinase inhibitor (TKI) therapy. The failure to eradicate these LSCs results in indefinite therapy dependence and a risk of leukemic relapse. However, the conventional LSC compartment (Lin-CD34+CD38-) is highly heterogeneous where only a sub population is believed to be functional, TKI-insensitive LSCs. Previously, using single-cell gene expression analysis we characterized the heterogeneity within the LSC population (Lin-CD34+CD38-) in CML patients. Interestingly, by comparing LSC heterogeneity at diagnosis with the heterogeneity following 3 months of TKI therapy we uncovered a therapy-insensitive, quiescent LSC-subpopulation, which could be isolated at high-purity using a combination of the surface markers: Lin-CD34+CD38-CD45RA-cKIT-CD26+ (Warfvinge, Geironson, Sommarin et al., 2017). Here, we expand the single-cell analysis of CML LSC populations to include combined immunophenotype-/RNA sequencing analysis (CITE-seq). By comparing LSCs from patients with different therapeutic outcome we describe how LSC heterogeneity at diagnosis correlate with long-term therapy response. We furthermore evaluate the potential for humanized ossicle-niche xenotransplantation (Reinisch et al., 2016) as a model system for functional characterization of LSC subpopulations in vivo.

Budget Impact of Treatment-Free Remission in Treating Chronic-Phase Philadelphia-Positive Chronic Myeloid Leukemia in Lebanon

PURPOSEChronic myeloid leukemia (CML) ranks second in terms of disease-related health care expenditures at the Lebanese Ministry of Public Health (MoPH) after breast cancer. With the introduction of tyrosine kinase inhibitors (TKIs), survival of patients with CML has dramatically improved and approached that of the normal population. In recent years, several studies demonstrated that patients who achieve a deep molecular response while receiving TKI therapy could safely attempt treatment-free remission (TFR), the new treatment goal in patients with CML. The objective is to estimate the budget impact of TFR at the MoPH.METHODSAnalyses were done on 162 patients with CML receiving imatinib, nilotinib, or dasatinib, as first-line or second-line therapy, over a 4-year time horizon using MoPH drug pricing. The model assumed that patients could attempt TFR after 36 months of TKI therapy, where the last 24 months were at stable molecular response as per MoPH and National Comprehensive Cancer Network guidelines. Duration of TFR was based on European Stop Kinase Inhibitor treatment-free survival curve.RESULTSOut of the 162 patients, 83 were eligible to attempt TFR, 36 patients were not eligible, 32 patients were lost to follow-up, two patients died as a result of CML progression, and five died as a result of other causes. The total cost of CML treatment with TFR from the time of analysis and over 4 years can be reduced by more than 7 million US dollars (57%).CONCLUSIONThe model can be used to inform health care decision makers on the importance of TFR and the potential savings.

Predictive value of early molecular response for deep molecular response in chronic phase of chronic myeloid leukemia.

To investigate the association of 3- and 6-month BCR-ABL transcript levels on the international scale (BCR-ABLIS) and other factors with deep molecular response (DMR) achievement in chronic myeloid leukemia (CML)-chronic phase (CP) patients receiving tyrosine kinase inhibitor (TKI) therapy.We retrospectively analyzed the clinical data of 206 patients enrolled in our hospital between January 2010 and July 2018. These patients were initially diagnosed with CML-CP and received imatinib or nilotinib therapy. Early molecular response (EMR) was assessed based on BCR-ABLIS (IS: on the international scale) transcript level at 3 and 6 months. Potential factors impacting DMR achievement were identified using Cox proportional hazard regression models. The effects of EMR achievement on the cumulative incidence of MR4.0 were investigated via Kaplan–Meier analysis.Multivariate Cox regression analysis showed that a BCR-ABLIS transcript level at 3 and 6 months of TKI therapy was an independent factor for the achievement of MR4.0, which was nevertheless not related to age, gender, Sokal score, hemoglobin level, or white blood cell (WBC) count at the initial time of diagnosis. Patients achieving an EMR (EMR: 3-month BCR-ABLIS ≤10%, 6-month BCR-ABLIS <1%) were more likely to reach MR4.0 than patients failing to achieve EMR (P1 <.001, P2 <.001). Patients who had 3-month BCR-ABLIS ≤1% were more likely to reach MR4.0 than those who had 3-month BCR-ABLIS of 1% to 10% or >10% (P1 = .001, P2 <.001). Similarly, patients who had 6-month BCR-ABLIS ≤0.1% were more likely to achieve MR4.0 than those in the 0.1% to 1% and ≥1% groups (P1 <.001, P2 <.001). Also, a higher percentage of patients on nilotinib therapy achieved EMR compared with patients on imatinib therapy (93.3% vs 63.6% on 3-month nilotinib therapy, P = .001; 88.9% vs 59.9% on 6-month nilotinib therapy, P = .004).This study demonstrates that EMR, especially a 3-month BCR-ABLIS ≤1% and 6-month BCR-ABLIS ≤0.1%, have predictive value for DMR achievement. In addition, there is a higher percentage of patients receiving nilotinib therapy achieved EMR than that of those receiving imatinib therapy.

Copy Number Variations in Cytochromes and Glutathione-Transferases As Early Predictors of the Efficacy of Tyrosine Kinase Inhibitors in CML

Chronic myeloid leukemia (CML) is characterized by the presence of the chimeric tyrosine kinase BCR-ABL in all leukemic cells. This non-specific enzyme promotes uncontrolled cell proliferation and genome instability. Tyrosine kinase inhibitors (TKI) help most of the people to achieve long standing remission, however up to 20% of patients develop slow response or even primary resistance to the therapy. In this work we focused on copy number variation (CNV) in glutathione transferases (GSTs) and cytochromes (CYPs) as possible predictors of the response rate to TKI. Thirty one CML patient with optimal response and 16 with therapy failure were enrolled in the study. Patient were grouped according to ELN2013 recommendations: BCR-ABL<1% and/or Ph+ 0% for optimal response and BCR-ABL>10% and/or Ph+ >35% at 6 months of TKI therapy for the failures. We found that these two groups of patients had differed frequencies of wild type and mutated genes: CYP1A2, CYP2A6, CYP2C19, CYP2C9, CYP2D6, CYP2E1, CYP3A4, CYP3A5, GSTM1, GSTP1, GSTT1 (p< 0.0013). Validation in the additional group of 15 CML patients showed that the test allows to predict failures and responders (p=0.02) with high accuracy: positive and negative predictive value 83% and 78%; sensitivity and specificity 71% and 88%. DisclosuresChelysheva:Novartis: Consultancy, Speakers Bureau; Bristol-Myers Squibb: Speakers Bureau. Shukhov:BMS: Honoraria; Novartis Pharma: Honoraria. Turkina:BMS: Honoraria; Novartis Pharma: Honoraria; Pfizer: Honoraria. Kutsev:Novartis: Speakers Bureau; Pfizer: Speakers Bureau.

Evaluation of the Risk of Hepatitis B Reactivation Among Patients with Chronic Myeloid Leukemia Treated with Tyrosine Kinase Inhibitors

▪Background: Immunosuppressive therapy is a known risk factor for hepatits B reactivation. The highest risk is reported in hematologic patients treated with anti-CD20 monoclonal antibodies, glucocorticoids and hematopoietic stem cell transplantation. Currently, treatment with tyrosine kinase inhibitors (TKIs) in the vast majority of chronic myeloid leukemia (CML) patients is life-long. Recently healthcare professionals were advised to test for hepatitis B infection before initializing therapy with TKIs and closely monitor HBV carriers. The risk is considered class effect with all TKIs and recommendations are based on case reports.Aim: The aim of the current study was to evaluate the risk of hepatitis B reactivation in patients with CML treated with TKIs.Methods: The records of patients with CML treated with TKIs from a single center were systematically reviewed for hepatitis B serology and serum biochemistry.Results: One hundred eighty one patients diagnosed with CML between the years 1983 and 2016 were evaluated. The median age at diagnosis was 49.7 years (range 18-89), 117/181 (65%) males, with median duration of follow up with TKI therapy of 5.3 years (range 0.4 to 33 years). Over a total of 1195 years of therapy with TKIs no cases of HBV reactivation were identified. Among 114 patients with hepatitis serology, 11 patients (10%) had evidence of prior resolved HBV infection (HBsAg negative/anti-HBc positive). Two of them had anti-HBs positive serology, one had negative PCR for HBV DNA and other two patients received lamivudine prophylaxis. Only one patient had HBsAg positive serology. None of the patients with positive hepatitis serology had clinical or biochemistry evidence of hepatitis B reactivation. The 67 patients without available hepatitis serology had normal liver transaminases at 6 months of TKI therapy and at last day of follow up, confirming that no overt hepatitis B reactivation occurred.Conclusions: We evaluated hepatitis B reactivation in a rather large cohort of CML patients, treated with TKIs. Although there were no cases of HBV reactivation during long term follow up, it should be emphasized that even a low incidence may exert a significant risk due to the long duration of treatment in a chronic disease with lifelong therapy. Our study infers that patients with serology of prior resolved HBV infection are at low risk for hepatitis B reactivation. Larger cohorts of patients with positive hepatitis B serology in a multicenter long term evaluation should be performed in order to address current recommendations for patients' safety and concerns. DisclosuresNo relevant conflicts of interest to declare.

Prevalence and Dynamics of BCR-ABL Independent Gene Mutations in Patients with Chronic Myeloid Leukemia

Living without treatment has become a realistic target for patients with chronic myeloid leukemia (CML) who achieved durable deep molecular remission under treatment with tyrosine kinase inhibitors (TKI). Recently, we have identified novel BCR-ABL-independent gene mutations in newly diagnosed CML patients that may function as important cofactors in the evolution of CML and persistence of the disease (Schmidt M, Rinke J, et al. Leukemia 2014; 28(12): 2292-9). Here, we sought to investigate the dynamics of such mutations during a 2-year treatment with the second generation TKI nilotinib. To check if BCR-ABL independent mutations are an age associated phenomenon we also screened a cohort of children and adolescents with CML. A total of 51 chronic phase CML patients were analyzed including 31 adults (male, n=23; median age 57 years, range 42 to 73 years) and 20 children/adolescents (male, n= 14; median age 14 years, range 10 months to 27 years). For each adult patient, samples were analyzed at diagnosis, in subsequent complete cytogenetic remission (CCyR) after 3 months and in deep molecular remission (≤ MMR) after 24 months of nilotinib therapy. Children/adolescents samples were investigated at diagnosis only. Targeted deep next-generation sequencing (NGS) was used to analyze a panel of 30 commonly mutated genes in myeloid disorders. Constitutional DNA obtained from buccal swabs at diagnosis was investigated to check whether mutations are of somatic origin. BCR-ABL independent gene mutations were found in 8/31 (26%) adult CML patients at diagnosis affecting the genes ASXL1 (n=3), DNMT3A (n=3), RUNX1 (n=1) and RUNX1 plus TET2 (n=1). No mutation was recognized in corresponding constitutional DNA specimens indicating that all mutations were somatically acquired. Analysis of individual hematopoietic colonies from three adult patients revealed that most mutations were part of the BCR-ABL-positive clone. NGS of subsequent samples obtained after three months of TKI therapy identified two DNMT3A mutations in BCR-ABL-negative cells that were also present in BCR-ABL-positive cells at diagnosis, implying that this mutation preceded the BCR-ABL rearrangement. After 24 months of TKI treatment, NGS revealed these two DNMT3A mutations again as well as a novel low-level EZH2 mutation in a patient with deep molecular remission (MR4.5) that was neither detectable at diagnosis nor after 3 months of treatment indicating the emergence of a BCR-ABL-independent subclone in BCR-ABL-negative cells during long-term nilotinib treatment. Within the children/adolescents cohort BCR-ABL independent gene mutations were identified in 5/20 (25%) subjects all affecting the ASXL1 gene. All mutations were stop codon or frameshift mutations implying loss of ASXL1 gene function. We conclude that BCR-ABL independent gene mutations can be found frequently in CML patients and affect predominately epigenetic modifier genes. The finding of frequent mutations also in children/adolescents implicates that BCR-ABL independent gene mutations are not just age-related events. Such molecular aberrations may play an important role in the evolution and persistence of the disease and may affect therapy in both children and adults with CML. These findings may provide important novel genetic information regarding CML biology and for the design and performance of discontinuation trials. DisclosuresHochhaus:Novartis: Honoraria, Research Funding; Pfizer: Honoraria, Research Funding; BMS: Honoraria, Research Funding; ARIAD: Honoraria, Research Funding.

A Randomized Phase II Trial of Interferon (IFN)/GM-CSF Versus K562/GM-CSF Vaccination in Chronic Phase CML Patients on Frontline Tyrosine Kinase Inhibitor (TKI) Therapy: Potential of IFN to Enhance Molecular Remissions

Background: Tyrosine kinase inhibitors (TKIs) have dramatically improved outcomes in chronic myeloid leukemia (CML), but most patients either never achieve a complete molecular remission (CMR) or recur upon TKI discontinuation due to the persistence of leukemic stem cells. The kinetics of the initial TKI response appear predictive of long term outcomes as front-line imatinib patients who achieve a major molecular response (MMR) at 12 months have a 72% chance of attaining a CMR versus just 5% for those who do not (median time on Imatinib (IM) prior to CMR 66 months) (Branford. Clin Cancer Res. 2007). Interestingly, patients who achieve and maintain a CMR for ≥2 years on single agent IM have been the subject of several TKI discontinuation trials demonstrating that 38-47% of such patients maintain treatment-free remissions (TFR) at 2 years (median time on IM prior to discontinuation of 50-70 months) (Mahon. Lancet Oncol. 2010 and Ross. Blood. 2013). Interferon-alpha (IFN) and K562/GM-CSF vaccines have been shown to enhance the frequency of deep molecular responses to TKIs (Preudhomme. N Engl J Med. 2010 and Smith. Clin Cancer Res. 2010). We have shown that IFN targets LSCs, which may be the mechanism of improved IM responses (Angstreich. Br J Haematol. 2005). We now report initial outcomes for patients randomized between these treatments as a means of achieving TFR.Methods: Patients with Ph+ CML in complete cytogenetic remission on first-line TKI treatment for ≥1 year were randomized to receive either K562/GM-CSF vaccination at 3 week intervals (vaccine) or daily interferon/GM-CSF (IFN/GM) in combination with their TKI. If CMR was achieved after a minimum of 6 months of adjuvant treatment, then all therapy was stopped, and monthly BCR-ABL PCR testing was performed to monitor for relapse. Based on the limits of detection of our assay, CMR is defined as at least MR4.3, which is IS <0.01. At disease recurrence, or if CMR was not achieved at 12 months of combination therapy, patients were allowed to cross-over. The treatment arms were defined as IFN alone (A), vaccine alone (B), IFN followed by vaccine (C), or vaccine followed by IFN (D).Results: 34 patients were enrolled with final treatment allocation shown in Table 1. Most patients were on IM (n=31), nilotinib (n=2) and dasatinib (n=1) with a median duration of TKI use at enrollment of 19 (range 12-80) months. Both arms of the trial were well-tolerated. The vaccine arm was notable for grade 1 and 2 injection site reactions in all patients. Predictably, the IFN arm produced grade 1 and 2 myalgias and flu-like symptoms in the majority of patients. Three patients had to discontinue treatment on the IFN arm due to grade 3 adverse events including a neurological event of unknown causality (1) and ALT elevation (2). Table 1 shows the responses by treatment arm with 62% of patients achieving CMR at a median of 28.6 (range 11-100) months of TKI therapy (compared to 66 months in IRIS). 15 patients (44%) discontinued TKI treatment per study plan after a median of 27.5 (range 19-56) months of TKI treatment (compared to median of 50-70 months of TKI in STIM/TWISTER), and 4 patients (27%) remain off therapy with TFRs of 64, 64, 85, and 92 months. Those with recurrence were off TKI for a median of 3 (range 1-5) months. Importantly, the long term responders who achieved CMR with adjuvant therapy all received IFN adjuvant, and all had relatively little prior TKI treatment (21, 27, 28, and 44 months) compared to published discontinuation studies. As expected in this group, all 4 had achieved a MMR at 12 months on TKI alone (p=0.05). What was unexpected was that 50% of patients treated with one of the IFN arms who had not achieved a MMR at 12 months on TKI alone went on to CMR after treatment on study compared to previous reports and just 15% of historical controls in our institutional database who achieved CMR on TKI alone (p=0.02)Conclusions: Adjuvant therapies may improve the likelihood of achieving CMR and allow for discontinuation of TKI in CML patients with minimal TKI exposure. Even patients predicted to not achieve CMR based on a lack of MMR at 12 months did so at a higher rate than expected following IFN treatment. IFN likely played a role in long term TFR in 4 exceptional responders who successfully discontinued IM sooner than in previously reported discontinuation trials, possibly owing to IFNs effect on primitive CML progenitors. [Display omitted] DisclosuresSmith:Actinium Pharmaceuticals, Inc.: Research Funding.

Single Cell Whole Transcriptome Analysis Reveals Distinct Molecular Signatures of Therapy-Resistant Chronic Myeloid Leukemia Stem Cells

Molecularly targeted therapy frequently induces remissions in cancer, but rarely achieves complete disease eradication, with resulting risk of disease relapse/progression. Chronic myeloid leukemia (CML) is a good example, with rare, propagating stem cells (SCs) that are incompletely eradicated by BCR-ABL directed tyrosine kinase inhibitor (TKI) therapy in most cases. Consequently, CML relapse usually occurs following treatment discontinuation. Further, some patients fail to achieve a satisfactory response to TKI therapy and are at risk of disease progression. Ultimately, the depth of response to TKIs is dictated by CML-SCs, however, it has proven challenging to characterise this crucial population of cells as they reside in the same compartment as their normal hematopoietic stem cell (HSC) counterparts from which they cannot be reliably distinguished throughout the disease course.Advances in single cell transcriptomics are opening up unprecedented opportunities to unravel heterogeneity in cell populations. However, to date, this technology has primarily been used to analyse normal tissues, partly reflecting the lack of sensitivity for detection of somatic mutations using current techniques. Herein, we developed a novel protocol allowing targeted amplification of BCR-ABL during single cell cDNA library generation using a modification of a published protocol (PMID:24385147). We then applied this method to analyse 1082 bone marrow SCs (defined as Lin-CD34+CD38-) from a cohort of 10 patients with CML and 3 normal controls.We first validated our method using the BCR-ABL +ve K562 cell line. Surprisingly, using standard methods, BCR-ABL was only detected in a small minority of cells. With our modified technique, we demonstrate robust detection of BCR-ABL in 100% of single K562 cells with parallel whole transcriptome amplification from the same cell. Further, using a plasmid Òspike-inÓ, we demonstrate sensitivity to detect a single molecule of BCR-ABL per cell, without false +ve BCR-ABL amplification in 142 cells tested. We then analysed 40 SCs from a patient with CML who was in a cytogenetic remission (CyR) following 3 months of TKI therapy. BCR-ABL was detected in 16 cells and was absent in 24 cells. With an average of 3.3 million mapped reads per single cell, we detected over 4600 genes per cell with good correlation of single cell ensemble data with bulk analysis. Using this approach we were uniquely able to compare BCR-ABL +ve and -ve cells and identify a large number of differentially expressed genes, which would not have been detected through bulk analysis. We selected a number of genes of biologic interest for validation by Q-PCR and 80% of them were confirmed as differentially expressed, a number of these are highlighted in the heatmap (see Figure).We then analysed 717 single SCs from 8 CML diagnostic samples. This analysis identified marked heterogeneity of BCR-ABL expression with frequencies comparable to the published literature (9% to 92%). Unsupervised clustering analysis revealed many genes that were differentially expressed between BCR-ABL +ve and -ve SCs e.g. CML-SCs showed upregulation of cell cycle signatures and decreased expression of HSC-affiliated genes. We next analysed 223 single SCs from a series of 5 patients in CyR following TKI initiation. BCR-ABL positive SCs could still be detected, albeit at a reduced frequency (0.5% to 45%). In contrast to the diagnostic samples, CML-SCs showed quiescence and HSC signatures that were comparable to normal HSCs. Furthermore, through analysis of serial samples from diagnosis to remission from the same patient, this single-cell approach uniquely allowed analysis of gene expression specifically of the CML-SCs which evade TKI therapy, facilitating the identification of a number of candidate gene-sets including cell surface markers and potentially ÒdruggableÓ targets. Finally, through analysis of a patient with early blast crisis transformation of CML during TKI therapy, we illustrate how single cell RNA sequencing might be applied to predict such early disease progression events.We herein describe a new approach for single cell RNA sequencing of CML-SCs that might be applied to fate-map persistent CML-SCs during and following treatment for discovery research and also to refine precision medicine in CML. This approach could be applied across a range of clonal disorders with potential broader relevance for cancer research. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Milestones and monitoring.

In chronic myeloid leukemia (CML), the presence of a specific chromosome marker (Ph-chromosome) as well as of the corresponding molecular marker (BCR-ABL fusion transcripts) provides suitable and precise tools to monitor the burden of the disease present at diagnosis and that of the residual disease present at specific time points during treatment. A huge number of studies have clearly demonstrated that in CML cytogenetic and molecular responses are strictly correlated to the final outcome of the patients and the correct use of standardized methods to assess the achievement of specific degrees of disease reduction at specific time points during treatment has become an essential part of proper clinical management of CML. The target to be achieved and the corresponding “optimal response” definition are however evolving, and at least for some patients, they may be represented not only by best possible overall survival (OS) but also by the possibility to discontinue the tyrosine-kinase inhibitor (TKI) treatment and therefore to live in a treatment-free remission (TFR) status. Therefore, at least for some patients, deep degrees of molecular response, as MR4 and MR4.5, whose precise definition has been recently introduced and that are prerequisites to try to discontinuation, are becoming the target to be achieved even in common clinical practice. As a fast initial decline of the disease burden after therapy start may be highly predictive for the final outcome of patients not only in terms of progression-free survival (PFS) and of PS but also in terms of possibility of achieving deep molecular responses, a more intense and punctual monitoring of the response of CML patients during the first 6 months of TKI therapy is now recommended by the more recent versions of the European Leukemia Net (ELN) and National Comprehensive Cancer Network (NCCN) guidelines, as this represents the major driver to decide therapy.