2G-TKI Therapy Research Articles

Outcome of Patients with Chronic Myeloid Leukemia in Chronic Phase Showing Clinical Resistance to Frontline Treatment with Second Generation Tyrosine Kinase Inhibitors. an Italian Prospective Study from the CML Campus

BACKGROUND: Frontline treatment with second generation tyrosine-kinase inhibitors (2G-TKIs) in patients with chronic myeloid leukemia in chronic phase (CP-CML) demonstrated higher efficacy as compared to imatinib therapy in inducing deeper molecular responses. However, its ability to reduce treatment failure and progressive disease is debated. Furthermore, limited information is currently available on the outcome of those CML patients showing clinical resistance to first-line treatment with a 2G-TKI. AIM: To describe the clinical outcome of CP-CML patients showing resistance to a frontline 2G-TKI and that switched to alternative TKIs therapy. PATIENTS AND METHODS: We performed this investigation on patients drawn from a web-based database (www.epiclin.it/lmc) used to collect clinical and biological data of CML patients enrolled in 24 Italian Hematology Centers from January 2013 onwards. Definitive information about first-line TKI treatment was available in 1277 prospective and consecutive CP-CML patients: 607 received imatinib and 670 dasatinib or nilotinib (2G-TKIs) as frontline therapy. Main inclusion criteria were: i) diagnosis of CP-CML; ii) first-line treatment with a 2G-TKI; iii) switch to second-line treatment in case of clinical resistance (i.e. failure according to ELN 2020 recommendations). Exclusion criteria was switch to second-line treatment for intolerance or for low adherence to therapy. Patients were treated according to the Center policy and the molecular data were obtained in accordance to the IS% parameters. RESULTS: Fifty-four CML patients met the inclusion/exclusion criteria and were identified as failure according to the ELN 2020 recommendations. The median age of these patients was 48.5 (20-81) years; male sex in 30 (55.5%) and female 24 (44.4%), Sokal risk score was low in 16 (29.6%), intermediate in 22 (40.7%) and high in 16 (29.6%) patients respectively;ELTS score was low in 26 (48.1%), intermediate in 14 (25.9%) and high in 14 (25.9%) patients. Additional chromosomal abnormalities were present at diagnosis in 4 out of 54 patients (7.4%: 3 additional Ph-chromosome and 1 trisomy 8). Nilotinib was administered in 27 (50%) and dasatinib in 27 (50%) of the patients.At 6 months, 30 out of 50 evaluable patients (60%) had BCR::ABL1 transcript values >1% and at 12 months 9 of 33 evaluable patients (28%) had BCR::ABL1 values still >1%. Second-line treatment after 2G-TKIs frontline failure started in all patients after a median time of 12 months (3-83) with ponatinib (30 pts, 55.5%), dasatinib (8 pts, 14.8%), nilotinib (4 pts, 7.4%), bosutinib (7 pts, 12.9%) or imatinib (5 pts, 9.2%).At 12 months the switch to second-line treatment induced the achievement of BCR::ABL1 values <1% in 45% of the evaluable cases. Eighteen patients (in which no mutations were found) switched to third-line treatment after a median time of 11 months (0-45) (ponatinib, 8 pts; nilotinib, 1 pt; dasatinib, 3 pts; imatinib, 3 pts; bosutinib, 1 pts; asciminib, 2 pts). MMR or a better response was reached by 6 of these patients and allogeneic stem-cell transplantation (SCT) was performed in 7 patients.Progression to CML advanced phase occurred in 8 pts. After a median follow-up of 59.9 months (15.6 - 99.3) 44 patients were still alive and death occurred in 10 pts (18.5%) (7 CML-related and 3 unrelated). Overall survival (OS) at 5 years was 82% (see Figure below). Indeed, OS at 5 years was 94% for the total 670 patients treated frontline with 2G-TKIs. In this population, 12 out of 32 observed deaths were CML-related and all were recorded in patients who changed TKI therapy, whereas in 19 cases the death was CML-unrelated and in 1 case was not specified. However, those patients who maintained the same therapy for 5 years showed an OS of 96%, whereas those who had to change treatment for any cause showed an OS of 89% at 5 years. CONCLUSION: Our findings, collected from the prospective cohort of the CML Italian observational registry, show that CP-CML patients failing frontline 2G-TKI therapy, despite a complex management, may have still an acceptable prognosis and survival due to the availability of both multiple TKI options and SCT.

Transplantation in CML in the TKI era: who, when, and how?

Molecular therapy with tyrosine kinase inhibitors (TKIs) has significantly reduced the indication for allogeneic hematopoietic stem cell transplantation (allo-HSCT) in chronic myeloid leukemia (CML). Treatment-free remission can be obtained in about 50% of patients with an optimal response. However, cure rates up to 90% are restricted to patients receiving HSCT. Timing is essential since HSCT in the early stages of the disease has the best outcome. Patients in a more advanced phase (AdP) than chronic-phase (chP) CML undergo HSCT with suboptimal outcomes, and the gap between chP and AdP disease is widening. First-line therapy should start with first- or second-generation (G) TKIs. Patients failing treatment (BCR-ABL1 transcripts of greater than 10% at 3 and 6 months and greater than 1% at 12 months) should be switched to second-line TKIs, and HSCT should be considered. Patients not responding to 2G-TKI therapy as well as patients in an accelerated phase (AP) or blast crisis (BC) are candidates for HSCT. Therapy resistant BCR-ABL1 mutations, high-risk additional cytogenetic abnormalities, and molecular signs of leukemia progression should trigger the indication for HSCT. Patients who, despite dose adjustments, do not tolerate or develop severe adverse events, including vascular events, to multiple TKIs are also candidates for HSCT. In AdP CML, TKIs do not show long-lasting results, and the outcome of HSCT is less optimal without pretransplant therapy. In these patients the induction of chP2 with TKIs, either alone (AP) or in combination with intensive chemotherapy (BC), followed by HSCT should be pursued.

Targeted Next-Generation Sequencing Identifies Additional Mutations Other than BCR∷ABL in Chronic Myeloid Leukemia Patients: A Chinese Monocentric Retrospective Study.

A proportion of patients with somatic variants show resistance or intolerance to TKI therapy, indicating additional mutations other than BCR∷ABL1 may lead to TKI treatment failure or disease progression. We retrospectively evaluated 151 CML patients receiving TKI therapy and performed next-generation sequencing (NGS) analysis of 22 CML patients at diagnosis to explore the mutation spectrum other than BCR∷ABL1 affecting the achievement of molecular responses. The most frequently mutated gene was ASXL1 (40.9%). NOTCH3 and RELN mutations were only carried by subjects failing to achieve a major molecular response (MMR) at 12 months. The distribution frequency of ASXL1 mutations was higher in the group that did not achieve MR4.0 at 36 months (p = 0.023). The achievement of MR4.5 at 12 months was adversely impacted by the presence of >2 gene mutations (p = 0.024). In the analysis of clinical characteristics, hemoglobin concentration (HB) and MMR were independent factors for deep molecular response (DMR), and initial 2GTKI therapy was better than 1GTKI in the achievement of molecular response. For the scoring system, we found the ELTS score was the best for predicting the efficacy of TKI therapy and the Socal score was the best for predicting mutations other than BCR∷ABL.

The Prognostic Impact of HMGCLL1 Gene Variant on Treatment Outcomes in Chronic Myeloid Leukemia (CML) Patients: Adverse Impact on the Response, Failure, and Progression with Imatinib Which Can be Abrogated By the Use of 2nd Generation Tyrosine Kinase Inhibitor (TKI) Upfront Therapy

BackgroundHMGCLL1 is characterized as a lyase activity enzyme located in the extramitochondrial region. Its biological and physiological role is not fully elucidated. Our previous study (Leukemia 2019) demonstrated that: 1) The HMGCLL1 gene variant, ACGTAATG haplotype (A-haplotype) is associated with increased expression of overall levels and isoform 3 (IS3) of the HMGCLL1 gene and predicts a decreased likelihood of deep molecular response after Imatinib (IM) therapy, 2) blockade of HMGCLL1 IS3 results in G0/G1 cell cycle arrest, leading to increased eradication of CML cell lines and CML leukemic stem cells, 3) blockade of HMGCLL1 isoform 3 significantly suppressed CD34+ fractions in CML patients (pts). It was unclear whether a second-generation tyrosine kinase inhibitor (2G-TKI) can reverse the adverse impact of the HMGCLL1 gene variant in CML pts. The present study assessed the prognostic impact of the HMGCLL1 gene variant in CML pts treated with IM or 2G-TKI, and its impact on treatment-free remission (TFR) after TKI discontinuation. Patients and methods Samples from 387 pts were sequenced. Group 1 included 252 pts from 2 centers whose samples were archived retrospectively. These pts were treated with IM (n=190, 75.3%) or second-generation TKIs (n=62) including Dasatinib (n=15, 6.0%), Nilotinib (n=37, 14, 7%), and Bosutinib (n=10; 4.0%). Group 2 included 135 patient samples from 4 countries that attempted to discontinue TKI for TFR. We applied our internal CML-specific smMIP panel with 332 amplicon probes including 8 HMGCLL1 SNPs (rs10948926, rs10948927, rs9370435, rs4546489, rs4275061, rs9475323, rs9475327, rs9296791). Linkage disequilibrium (LD) was assessed using Haploview software (Bioinformatics 2005). For Group 1, treatment outcomes were evaluated concerning major molecular response (MMR), molecular response (MR) with 2 log/deeper (MR2) or 4 log/deeper (MR4), failure-free survival (FFS), progression, and overall survival (OS). Disease characteristics and treatment outcomes were evaluated and compared according to the HMGCLL1 variants using a dominant model. For Group 2, molecular relapse-free survival (RFS) was calculated from the date of TKI discontinuation to the date of confirmed loss of molecular response (either loss of major MMR or two consecutive episodes of MR loss). Kaplan-Meier survival estimate was used to evaluate RFS and Cox's proportional hazard regression model was applied using the dominant model. Results HMGCLL1genotype and haplotype As shown in Fig A, the LD plot showed no recombination among the 8 SNPs, leading to one block for the 8 SNPs to construct a haplotype. Two haplotypes were constructed as CTCAGGCA (C-) or ACGTAATG (A-haplotype) with MAF of 0.674:0.279 in Group 1, and 0.703:0.216 in Group 2, respectively. Summary of outcomes in table 1. Treatment outcomes following TKI therapy according to the HMGCLL1 haplotype Homozygous A-haplotype (A/A) was associated with worse outcomes, showing a lower MR2 (65.9% vs 78.9% at 12 months, p=0.012), lower MMR (64.4% vs 86.8% at 3 years, p=0.00029), lower MR4 (34.7% vs 62.3% at 5 years, p=0.0001; worse FFS (62.8% vs 77.3% at 3 years, p=0.0014), higher risk of progression (16.2% vs 3.4% at 5 years, p=0.000678), and worse OS (56.1% vs 77.7% at 10 years, p=0.0021). The adverse impact of A/A-haplotype was more prominent in the pts treated with Imatinib: A/A-haplotype pts showed a 30-50% lower chance of MR2, MMR, and MR4 achievement, and 2-3 times higher risk of TFR and progression in comparison to those having C-haplotype when treated with Imatinib. However, the use of 2G-TKIs could abrogate the adverse impact of the A/A-haplotype. Impact of HMGCLL1 variant on treatment-free remission following TKI discontinuation While the 12-month RFS rate was 59.9% in overall pts (n=135), an inferior 12-month RFS rate was noted in A/A haplotype (43.8% vs 62.3%) but with borderline significance (p=0.116). Conclusion: The present study demonstrated that the HMGCLL1 gene variant is confirmed as predictive of CML outcomes. Moreover, our result suggests that the adverse impact of the HMGCLL1 genotype can be abrogated by using 2G-TKIs as upfront therapy. We aim to validate this data in a larger cohort of pts treated with 2G-TKI therapy to reach a clearer conclusion on this result. HMGCLL1 genotype information would be helpful to guide CML therapy given that pts with adverse HMGCLL1 genotypes could benefit from 2G-TKI therapy as front-line therapy. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Subjects with Chronic Myeloid Leukemia Identified As Intermediate- or High-Risk Subjects Using the Imatinib Therapy Failure (IMTF) Model Benefit from Initial Therapy with a Second-Generation Tyrosine Kinase Inhibitor

Objective Validate the imatinib therapy failure (IMTF) model in 3,752 subjects with chronic phase chronic myeloid leukemia (CML) receiving initial imatinib therapy, and further test prediction accuracy in 1,353 persons receiving initial a second-generation tyrosine kinase inhibitor (2G-TKI). Compare the cumulative incidences of therapy failure in each IMTF risk cohort between initial imatinib and a 2G-TKI therapy. Methods Data from 1,356 consecutive subjects with chronic phase CML receiving initial imatinib therapy at one centre (Beijing, China) were interrogated as an internal dataset and compared with results in 2,396 similar subjects from 65 other centers in China, an external dataset to validate the IMTF model (https://www.nature.com/articles/s41375-022-01527-y.) The IMTF model divided subjects into the very low-, low-, intermediate-, high- and very high-risk cohorts. Data from 1,353 subjects receiving initial 2G-TKI therapy were also interrogated using the IMTF model to extensionally test predictive performance. Propensity score matching (PSM) was used to adjust the differences in baseline co-variates between subjects receiving initial imatinib or a 2G-TKI. Results In the imatinib internal validation dataset, 467 (34%), 263 (19%), 302 (22%), 219 (16%) and 105 (9%) subjects were classified as the very low-, low-, intermediate-, high- and very high-risk cohorts. 5-year cumulative incidences of therapy-failure were 7% (95% Confidence Interval [CI] 4, 9%), 19% (15, 23%), 33% (29, 37%), 52% (46, 58%) and 78% (67, 89%; p < 0.001; Figure 1A). Hazard ratios (HRs) (very low-risk cohort as reference) were 2.6 (1.7, 4.0; p < 0.001), 4.3 (2.9, 6.3; p < 0.001), 6.4 (4.3, 9.5; p < 0.001) and 11.3 (7.5, 17.2; p < 0.001; p for trend < 0.001; Figure 1B). In the imatinib external validation dataset, 575 (24%), 589 (24%), 696 (29%), 420 (18%) and 116 (5%) were classified as the very low-, low-, intermediate-, high- and very high-risk cohorts. 5-year cumulative incidences of therapy-failure were 9% (7, 11%), 21% (16, 26%), 36% (25, 47%), 41% (33, 50%) and 58% (46, 70%; p < 0.001; Figure 2A). HRs (very low-risk cohort as reference) were 2.0 (1.5, 2.8; p < 0.001), 4.0 (3.0, 5.3; p < 0.001), 4.9 (3.6, 6.6; p < 0.001) and 6.9 (4.8, 9.9; p < 0.001; p for trend < 0.001; Figure 2B). In the internal 2G-TKI dataset, 74 (24%), 55 (18%), 67 (21%), 69 (22%) and 44 (15%) subjects were classified as the very low-, low-, intermediate-, high- and very high-risk cohorts. 5-year cumulative incidences of therapy-failure were 10% (4, 15%), 15% (3, 27%), 19% (5, 33%), 36% (13, 59%) and 63% (44, 82%) (p < 0.001; Figure 3A). There were no significant differences in therapy failure among the cohorts except those in the high- and very-high risk. In the external 2G-TKI dataset, 287 (27%), 227 (22%), 284 (27%), 179 (17%) and 67 (7%) subjects were classified very low-, low-, intermediate-, high- or very high-risk cohorts. 5-year cumulative incidences of therapy-failure were 3% (0, 6%), 10% (4, 16%), 18% (6, 31%), 24% (12, 36%) and 52% (25, 79%; < 0.001; Figure 3B). In PSM analyses, subjects in the intermediate- and high-risk cohorts in the 2G-TKI internal dataset receiving initial 2G-TKI therapy had significantly lower cumulative incidences of therapy-failure compared with those receiving initial imatinib therapy (p = 0.038 and 0.018) whereas therapy-failure was similar in the very low-, low- and the very high-risk cohorts (p = 0.42 - 0.47, Figure4A-4E). Similar results were obtained in the 2G-TKI external dataset (Figure4F-4J). Conclusions The IMTF model accurately predicts therapy failure in persons receiving initial imatinib therapy and in those receiving initial 2G-TKI therapy. Subjects identified as intermediate- and high-risk using the using the IMTF model might benefit from initial 2G-TKI therapy whereas those in lower risk cohorts might not. If further validated by randomized controlled trial (in process), our data on preferred initial therapy should help physicians optimize TKI-therapy strategy in persons with chronic phase CML. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Targeted Next-Generation Sequencing Identifies Additional Mutations Other Than BCR-ABL in Chronic Myeloid Leukemia Patients: A Chinese Monocentric Retrospective Study

The discovery of tyrosine kinase inhibitors (TKIs) has drastically changed the treatment of chronic myeloid leukemia (CML) patients. However, a proportion of patients still show resistance or intolerance to TKI therapy. These patients often carry somatic variants related to myeloid malignancies, indicating that additional mutations other than BCR-ABL1 may lead to TKI treatment failure or disease progression. We retrospectively evaluated 151 CML patients receiving TKI therapy and performed next-generation sequencing (NGS) analysis of 22 CML patients to explore the mutation spectrum other than BCR-ABL1 affecting the achievement of molecular responses. We also performed a comprehensive evaluation of clinical characteristics, distinct TKI options and scoring systems in the correlation with the molecular response of TKI. In total, 161 variants were detected by NGS, most of which were nonsynonymous SNVs (Figure A). The coexistence pattern among high-frequency variants was quite intricate(Figure B). Among 25 genes with allele mutation frequency (VAF) ≥5%, the most frequently mutated gene was ASXL1 (40.9%), followed by KMT2C (27.3%), DIS3 (18.2%), ATM (13.6%), DNMT3A (13.2%) and NOTCH3 (13.6%) (Figure C). NOTCH3 and RELN mutations were only carried by subjects failing to achieve a major molecular response (MMR) at 12 months, suggesting CML patients with NOTCH3 and RELN mutations might have poor long-term treatment effects (Figure D, Figure E). The distribution frequency of ASXL1 mutations was higher in the group that did not achieve MR4.0 at 36 months (P=0.023), indicating that ASXL1 mutation was an adverse factor for the achievement of MR4.0. Furthermore, subjects in this group possessed more mutations related to activation signaling pathway genes (P=0.003) and chromatin modification genes (P=0.029) (Figure F). In the group that failed to achieve MR4.5 at 12 months, there were more subjects carrying >2 gene mutations (9.1% vs. 63.6%, P=0.024), implying that it is less likely to achieve MR4.5 with the increase in the number of mutated genes and that the existence of more than two mutations is a poor prognostic factor for achieving deep molecular response (DMR) (Figure G, Figure H). However, no statistical significance was found in the effects of mutations in ASXL1 (P=0.371), KMT2C (P=0.079), DIS3 (P=0.467), ATM (P=0.280), DNMT3A (P=0.479) and NOTCH3 (P=0.479) on PFS. In the analysis of clinical characteristics, multivariate analysis identified hemoglobin concentration (HB) (relative risk, [RR], 1.023; P=0.08) and BCR-ABLIS level at 12 months (RR, 2.485; P＜0.001) as independent predictive covariates for MR4.5(Figure I). Subjects who received initial second-generation TKI (2GTKI) were more likely to achieve early molecular response (EMR) at 3 months (P=0.012), BCR-ABLIS ≤1% at 6 months (P=0.012) and MMR at 12 months (P=0.018) than initial first-generation TKI (1GTKI). And there did not show statistical significance in achieving BCR-ABLIS≤1% at 6 months, MMR at 12 months and MR4.5 between original 1GTKI (Group A1, Glevic, Novartis, Switzerland) and generic 1GTKI (Group A2, Genike, Chiatai Tianqing Pharmaceutical Group Co., Ltd.). As for scoring system, ELTS score was sensitive in differentiating whether patients could achieve EMR (P=0.001) and MMR (P=0.004). EUTOS scoring system had a significant difference in achieving MMR at 12 months (P=0.049). However, there was no significant difference in subjects stratified by the Hasford and Sokal scoring systems. In conclusion, ASXL1 mutation, activation signal pathway genes, chromatin modification genes and the presence of >2 mutations were adverse factors in achieving molecular response with TKI treatment. HB and MMR were independent factors for DMR, and initial 2GTKI therapy was better than 1GTKI in the achievement of molecular response. For the scoring system, we found that the ELTS score was the best in predicting the efficacy of TKI therapy. Acknowledgement: The work was supported by the Key R&D Program of Zhejiang (No. 2022C03137.), Public Technology Application Research Program of Zhejiang, China (No. LGF21H080003.), the Key Project of Jinhua Science and Technology Plan, China (No. 2020-3-011.), the 2019-2022 Key Medical Discipline (Haematology) Fund of Jinhua, China. Correspondence to: Dr Jian Huang, The First Affiliated Hospital of Zhejiang University School of Medicine. No. 79 Qingchun Road. Hangzhou, Zhejiang, PR China. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Somatic Mutations in Myeloid Transcription Factors and in Activated Signaling Pathway, but Not in Epigenetic Modifier Pathway, Predict the Risk of Treatment Failure and Progression to Advanced Phase in Chronic Myeloid Leukemia

Background Next-generation sequencing (NGS) is currently reforming contemporary clinical practice into precision medicine incorporating genomics-based knowledge into the clinic. Recently, multiple studies showed that mutations in epigenetic modifier genes are associated with poor treatment outcomes following tyrosine kinase inhibitor (TKI) therapy in chronic myeloid leukemia (CML), particularly after Imatinib treatment. However, it is uncertain whether they either originated from clonal hematopoiesis or the CML clone. For example, ASXL1 mutation is the most recurrent mutation at CML diagnosis, and its presence is correlated with adverse prognosis in CML. Finding of rapid reduction in ASXL1 allele frequency following TKI therapy (Kim et al, Blood 2017) raises the question of whether it is a real driver of treatment failure in CML or not. In addition, it is of interest whether 2nd generation TKI (2G-TKI) therapies can abrogate the adverse impact of somatic mutations in CML. Accordingly, the present study attempted to evaluate the prognostic impact of mutation profiles on clinical outcomes in CML patients treated either with Imatinib or 2G-TKIs. Patients and Methods Our cohort includes a total of 394 samples including 254 samples collected at initial diagnosis and 140 samples taken during follow-up from 309 CML patients in two CML treating centers. Disease characteristics and treatment outcomes were evaluated and compared according to mutation profiles at initial diagnosis and during follow-up after TKI therapy. Treatment outcomes include any response with respect to major molecular response (MMR), molecular response (MR) with 2-log/deeper (MR2) or 4-log/deeper (MR4) with any lines of TKI therapy, failure-free survival (FFS), progression and overall survival (OS). Instead of conventional NGS, we applied smMIP-based NGS (limit of detection up to 0.2%) using our in-house CML-specific panel targeting 40 genes including epigenetic modifiers, myeloid transcription factors (TFs), tumour suppressors, genes in activated signaling, spliceosome and, cohesin complex. ResultsPatient group and treatment summary Summary of patient characteristics are as follows: median age of 54 years; male:female n=143/111 (56.3:43.7); disease status at presentation includes chronic- (n=233; 91.7%), accelerated- (n=15; 5.9%), blastic phase (n=4; 1.6%), or N/A (n=2; 0.8%); Sokal score, low (n=61, 24.0%), intermediate (n=84, 33.1%), high (n=74, 29.1%), or N/A (n=35, 13.8%). Frontline therapy includes Imatinib (n=190; 74.8%), or 2G-TKI (n=62) including Dasatinib (n=15; 6.0%), Nilotinib (n=37; 14.7%), Bosutinib (n=10; 4.0%), or other (n=2; 0.8%). Mutation profiles and their correlation with clinical outcomes following TKI therapy70 mutations were detected in 57 (22.4%) out of 254 diagnostic samples, while 64 mutations were detected in 39 (27.9%) out of 140 follow-up samples.Any mutation detected at initial diagnosis is associated with worse outcomes following TKI therapy. The adverse impact of somatic mutation was mainly from myeloid TF or activated signaling pathway mutations. Patients having those mutations at initial diagnosis showed higher risks of treatment failure (HR 2.8 95% CI [1.4-5.4], p = 0.003) and progression (HR 3.1 95% CI [1.1-9.1], p = 0.04), mainly when treated with Imatinib. On the other hand, the adverse impact of epigenetic modifiers was not apparent although a trend was observed toward a lower response rate for MR2 and MMR in patients carrying mutations in epigenetic modifiers.The adverse prognostic impact from these mutations seems to be abrogated by the use of 2G-TKI therapy, supporting the use of smMIP-based NGS for upfront TKI selection in newly diagnosed CML patients.In the cross-sectional analysis of follow-up samples, overall mutation frequency was significantly higher in the treatment failure or progression group compared to the optimal responders (p=0.012), suggesting longitudinal tracking of mutation profiles may help identify cases of impending treatment failure or progression early. Conclusion Our study shows that mutation profiling utilizing smMIP-based NGS can help identify patients with a potential adverse prognosis from initial diagnosis and may help upfront TKI selection. Further follow-up analysis is ongoing to evaluate the effect of TKI therapy on longitudinal kinetics of mutations in serially collected samples. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

A Predictive Scoring System for Therapy Failure in Persons with Chronic Myeloid Leukemia Receiving Initial a Second-Generation Tyrosine Kinase Inhibitor Therapy

Purposes Develop and validate a predictive scoring system for therapy failure in persons with chronic phase chronic myeloid leukemia (CML) receiving initial a second-generation tyrosine kinase inhibitor (2G-TKI). Methods Data from 329 consecutive subjects with CML receiving initial 2G-TKI therapy at one centre (Beijing, China) in a training dataset were interrogated to develop a predictive model which was then validated in 1,083 subjects from 65 other centers in China. Therapy-failure was defined using the 2020 ELN criteria including progression to accelerated or blast phases or CML-related death. Fine-Gray model was used for uni- and multi-variable analyses (UVA and MVA) to identify co-variates significantly-associated with therapy-failure. Akaike information criterion (AIC) was used to select prognostic co-variate and determine the best model. 1000 bootstrap re-samplings, Fine-Gray test, the minimal p-value approach, Bonferroni correction and kernel density estimator were used to determine optimal cut-offs to classify subjects into risk cohorts. Time-dependent receiver-operator characteristic curves (ROC) were used to estimate prediction accuracy and calibration plots used to determine concordance between predicted and observed cumulative incidences. Decision curve analysis (DCA) was used to calculate the net benefit using the model. Results In the training dataset, 279 subjects (85%) initially received nilotinib; and 50 (15%), dasatinib. Median 2G-TKI therapy-duration was 36 months (interquartile range [IQR], 24-68 months). 75 subjects (23%) had therapy-failure at a median of 9 months (IQR 3-12 months) after therapy start. In MVA, increasing splenomegaly and a higher percentage blood blasts were significantly-associated with the higher cumulative incidences of therapy-failure. We used these data to develop a predictive scoring system: "2G-TKI failure risk score= 0.6405×[(spleen size below the costal margin in cm + 0.2)/10] + 0.1348×(blood blasts + 0.2)" which divided subjects into low- (score ≤ 0.3021; n = 89; 31%), intermediate- (0.3021 < score < 1.4508; n = 155; 54%) and high-risk (score ≥ 1.4508; n = 43; 15%) cohorts with 5-year cumulative incidences of therapy-failure of 3% (95% Confidence Interval [CI], 0, 5%), 26% (20, 32%) and 72% (56, 88%; p-value for trend < 0.001; Figure 1A). Hazard ratios (HRs) for therapy-failure (low-risk cohort as reference) were 4.8 (1.7, 13.6; p = 0.002) and 16.5 (5.7, 47.6; p < 0.001; p for trend < 0.001) for the intermediate- and high-risk cohorts. In the external validation dataset, subjects were classified into the low- (n = 433; 40%), intermediate- (n = 583; 54%) and high-risk (n = 67; 6%) cohorts using our scoring system. 5-year cumulative incidences of therapy failure were 8% (3, 13%), 18% (12, 25%) and 44% (29, 60%; p for trend < 0.001; Figure 1B). HRs (low-risk cohort as reference) were 2.7 (1.9, 3.6; p < 0.001) and 10.6 (5.8, 15.4; p < 0.001; p for trend < 0.001) for the intermediate- and high-risk cohorts. In the training dataset cohort time-dependent AUROC curves for therapy-failure at 1-, 3-, and 5-years in the model were 0.73-0.82 and 0.68-0.75 in the validation dataset. Calibration plots for the 1-, 3- and 5-years cumulative incidences of therapy-failure indicated good concordance between predicted and observed outcomes. DCA curves indicated net benefit from using the predictive scoring system in clinical settings. Conclusions We developed and externally validated a therapy-failure scoring system in persons with chronic phase CML receiving initial 2G-TKI. The model had high AUROCs and performed well in calibration plots and DCAs. Our model may help physicians decide appropriateness of initial the 2G-TKI therapy including possible selection of appropriate haematopoietic cell transplant candidates. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

P722: IS THE SECOND-GENERATION TYROSINE KINASE INHIBITOR A BETTER THERAPY THAN IMATINIB FOR PERSONS WITH CHRONIC MYELOID LEUKEMIA PRESENTING IN ACCELERATED-PHASE?

Background: Although most patients with chronic myeloid leukemia (CML) were presenting in the chronic phase at diagnosis, approximately 5% presented with features of accelerated phase. The features of accelerated phase were variably defined by different criteria, such as MD Anderson and European LeukemiaNet (ELN) criteria most often used. Regardless of these criteria used to defined accelerated phase, only scant data were available regarding the prognostic co-variates for outcome. Moreover, evidence that patients could benefit more from the second generation (2G-) tyrosine kinase inhibitor (TKI) than imatinib as initial therapy was still extremely limited. Aims: Explore whether patients with chronic myeloid leukemia (CML) presenting in accelerated-phase could benefit from initial second-generation tyrosine kinase inhibitor (2G-TKI) therapy. Methods: We interrogated data from consecutive patients with CML presenting in accelerated phase at diagnosis by the MD Anderson criteria (n = 325) or ELN criteria (n = 275). Propensity score matching (PSM) analysis was used to compare cytogenetic and molecular responses and outcomes in those receiving initial imatinib versus a 2G-TKI. COX multi-variable regression model was performed to identify the prognostic co-variates. Results: In the cohort defined by MD Anderson criteria, PSM analysis showed that patients receiving initial 2G-TKI (n = 89) had higher probability of achieving a CCyR (p = 0.01), MMR (p = 0.04) and MR4.5 (p = 0.004) than those receiving imatinib (n = 156), however, probabilities of FFS, PFS and survival were similar. Multi-variable analyses showed that lower platelets and higher blasts in blood or bone marrow were significantly-associated with poor FFS, PFS and/or survival (Figure A). In an attempt to determine whether choice of therapy contributed to the differences in responses and outcomes, platelets < 600 × 10E+9/L and blood / bone marrow blasts ≥ 5% were identified as the prognostic categorical co-variates by ROC analyses. The entire cohort were classified into low- (possessing none of these co-variates, n = 57), intermediate (possessing any 1 of these co-variates, n = 127) or high-risk (possessing all of these co-variates, n = 61) subgroups. There were significant differences in probabilities of outcomes among these risk subgroups (all p values < 0.001, Figure B). In each risk subgroup, patients receiving initial 2G-TKI had the similar outcomes to those receiving imatinib except higher incidences of responses including CCyR, MMR and MR4.5. The same results were observed in the cohort defined by ELN criteria. Image:Summary/Conclusion: Initial 2G-TKI lead to similar outcomes as imatinib in patients with CML presenting in accelerated-phase except higher therapy responses.

The 15 Year Long-Term Survival of Patients with Chronic Myeloid Leukaemia from 35 Regions of Russian Federation: A Follow up of a Multicenter Observation Study Eutos Osp Initiated By European Leukemia NET

The results of long-term follow-up of patients (pts) with chronic myeloid leukemia (CML) do not lose their importance. Data from routine clinical practice are of particular interest. The use of 1 st (imatinib, IM) and 2nd generation TKI (2G TKI) led to a significant increase in survival, so the probability of death associated with CML could be significantly lower than the probability of death due to common causes of death other than CML.To analyze the overall survival (OS) and causes of mortality in CML pts treated in routine clinical practice in Russian Federation for a long period (>15 years) of time.The long-term follow-up data of the Russian part of the European LeukemiaNet (ELN) OSP EUTOS multicenter observational study were evaluated. The analyzed cohort consisted of 678 Ph/BCR-ABL-positive CML pts from 35 regions of Russia diagnosed in 2002-2006 with IM therapy initiation ≤6 months (mo) after diagnosis. Median (Me) age was 47(range 18-81) years (y), 47% males. Chronic phase, accelerated phase and blast crisis at diagnosis was in 631 (93%), 41(6%) and 6(1%) pts, respectively. The annual number of newly diagnosed pts was as follows: 2002 - 15 pts, 2003 - 38 pts, 2004 - 46 pts, 2005 - 206 pts, 2006 - 302 pts. The last update for 209 pts was done in Jun. 2021; last contact for 100 pts - in 2020, for 39pts - in 2019, for the other - before 2018. The date of the last contact/death could not be established for 14 pts. Statistical analysis included 661 pts, the OS was evaluated by Kaplan-Mayer method using the SAS 9.4 package.In total, 331 (50%) pts of the analyzed cohort were alive with the Me follow-up of 180 (range 2-232) mo or 15 y (range 2 mo-19,3 y). All pts started therapy with IM with 25% switched to 2G TKI in subsequent therapy lines. In total, 218 (66%) pts achieved MR4, 183 (55%) pts got MMR; 46 (21%) of these pts with deep molecular response (DMR) were observed in hematology centers of Moscow.The 15-y OS in the total cohort was 63% (CI 59-70%)(fig.1). The OS by age groups was as follows: 18-40yy-75% (CI 73-82%), 40-60yy- 63% (CI 59-70%), 60-80yy- 37% (CI 30-45%). The most complete information was provided by Moscow centers (2 centers, 113 pts). The 15-y OS of pts receiving treatment in Moscow was significantly higher vs pts from other regions (32 centers, 548 pts): 75% vs 60%, p=0,0030 (fig.2).The mortality in the whole cohort of 661 pts was 35% (233 pts). Of these 233 pts, 112(48%) pts deaths were due to CML progression to AP or BP (including non-compliant cases); 3pts (1,5%) died after allogenic stem cell transplantation (infection complications); the cause of death was unknown in 50 (21,5%) pts. The highest death rate from CML progression was at 4-9 y of follow-up. Deaths caused by concomitant diseases were in 68 (29%) pts: coronary artery disease/myocardial infarction/heart failure in 42 (62%) of 68 pts, acute ischemic stroke in 10 (15%) pts, second malignancies (Cr- cancer) in 10 (15%) pts (lung tumor, metastatic esophageal Cr, stomach Cr, brain tumor, sigmoid colon Cr, rectal colon Cr, melanoma, renal Cr, breast tumor, other hematological malignancies), accidents - 1 pt, liver cirrhosis - 2 pts, in 2 cases - respiratory virus infections complicated with pneumonia, 1 pt died due to Covid-19.Conclusions. The long-term follow-up of the multicenter study EUTOS OSP in 35 regions of Russian Federation allows not only to characterize the 15-y OS in CML pts but also provides the long-term outlook of the routine clinical practice. Probably, better OS of CML patients receiving treatment in Moscow (2 centers) may be related to organizational issues of interaction with the federal center, better monitoring and timely switching to 2G TKI therapy. The organization and support of multicenter studies may improve the situation with the treatment of diseases of the blood system. [Display omitted] DisclosuresChelysheva: Novartis Pharma: Speakers Bureau; Pfizer: Speakers Bureau; Pharmstandart: Speakers Bureau; Bristol Myers Squibb: Speakers Bureau. Vinogradova: Pharmstandart: Speakers Bureau; Novartis Pharma: Speakers Bureau; Pfizer: Speakers Bureau; Bristol Myers Squibb: Speakers Bureau. Lomaia: Novartis: Honoraria; Pfizer: Honoraria; BMS: Honoraria; Pharmstandard: Honoraria. Voloshin: Abbvie: Consultancy, Speakers Bureau; Novartis: Consultancy, Speakers Bureau; Astra Zeneca: Consultancy, Speakers Bureau; Pfizer: Consultancy; Biacad: Consultancy, Speakers Bureau. Turkina: Pharmstandart: Speakers Bureau; Pfizer: Speakers Bureau; Bristol Myers Squibb: Speakers Bureau; Novartis Pharma: Speakers Bureau.

Step-in Dosing in the Bosutinib Dose Optimization Study (BODO) Failed to Reduce Gastrointestinal (GI) Toxicity in Patients Failing Second Generation TKI (2G-TKI) in Chronic Phase Chronic Myeloid Leukemia (CML) but Suggests Promising Molecular Response

Step-in Dosing in the Bosutinib Dose Optimization Study (BODO) Failed to Reduce Gastrointestinal (GI) Toxicity in Patients Failing Second Generation TKI (2G-TKI) in Chronic Phase Chronic Myeloid Leukemia (CML) but Suggests Promising Molecular Response

Is the Sokal or EUTOS long-term survival (ELTS) score a better predictor of responses and outcomes in persons with chronic myeloid leukemia receiving tyrosine-kinase inhibitors?

Data from 1661 consecutive subjects with chronic-phase chronic myeloid leukemia (CML) receiving initial imatinib (n = 1379) or a 2nd-generation tyrosine-kinase inhibitor (2G-TKI; n = 282) were interrogated to determine whether the Sokal or European Treatment and Outcome Study for CML (EUTOS) long-term survival (ELTS) scores were more accurate responses and outcome predictors. Both scores predicted probabilities of achieving complete cytogenetic response (CCyR), major molecular response (MMR), failure- and progression-free survivals (FFS, PFS), and survival in all subjects and those receiving imatinib therapy. However, the ELTS score was a better predictor of MR4, MR4.5, and CML-related survival than the Sokal score. In subjects receiving 2G-TKI therapy, only the ELTS score accurately predicted probabilities of CCyR, MMR, MR4, FFS, and PFS. In the propensity score matching, subjects classified as intermediate risk by the ELTS score receiving a 2G-TKI had better responses (p < 0.001~0.061), FFS (p = 0.002), and PFS (p = 0.03) but not survival. Our data suggest better overall prediction accuracy for the ELTS score compared with the Sokal score in CML patients, especially those receiving 2G-TKIs. People identified as intermediate risk by the ELTS score may benefit more from initial 2G-TKI therapy in achieving surrogate endpoints but not survival, especially when a briefer interval to stopping TKI therapy is the therapy objective.

Clinical outcome of chronic myeloid leukemia patients who switch from first-line therapy with a second generation tyrosine kinase inhibitor to an alternative TKI

While second generation tyrosine kinase inhibitors (2GTKIs) are highly effective therapies for chronic myeloid leukemia (CML), a significant minority of patients who initiate a 2GTKI will require a switch to an alternative TKI. The long-term outcomes of those who require a change in therapy after front-line 2GTKI therapy are largely undescribed. Here we describe the clinical outcomes associated with switch to an alternative TKI after first-line therapy with a 2GTKI. Of 232 patients who initiated a 2GTKI during the study period, 76 (33 %) switched to an alternative TKI. Reasons for switching included intolerance (79 %) and resistance (21 %). Among the 60 patients who switched due to intolerance, 53 (88 %) were able to achieve or maintain a major molecular response (MMR) with 5-year progression-free survival (PFS) 90.5 % (95 % CI 90.4–90.6 %). Amongst the 16 patients who switched due to resistance, 8 patients (50 %) were able to achieve MMR with 5-year PFS 80.4 % (95 % CI 80.2–80.6 %). Most patients who switched due to intolerance remained on their second-line TKI. Approximately 25 % of patients who initiate first-line 2GTKI in a real world setting will ultimately switch to an alternate TKI due to intolerance. Patients who switch for intolerance continue to enjoy excellent clinical outcomes.

Sequential Treatments in Chronic Phase Chronic Myeloid Leukemia (CML) Patients without Optimal Response after Frontline Nilotinib or Dasatinib: An Italian CML Campus Study

INTRODUCTION: Frontline therapy with second generation (2G) tyrosine-kinase inhibitors (TKIs) in chronic phase (CP) chronic myeloid leukemia (CML) patients demonstrated higher efficacy as compared to imatinib, with less patients experiencing treatment failure and progression to advanced disease. However, limited information are currently available on the management and outcome of those CML pts not achieving an optimal response to first-line treatment with a 2G-TKI. AIM: To describe the clinical outcome of CP CML patients without an optimal response to a frontline 2G-TKI that switched to alternative TKIs. METHODS: We performed a retrospective analysis in 22 Centers cooperating within the Italian CML Campus Project. Main inclusion criteria were: 1) diagnosis of CP-CML after 2010; 2) first-line treatment with a 2G-TKI; 3) switch to second-line treatment in case of non-optimal response (either following ELN recommendations or as for clinical practice); 4) CML in CP at the time of switching to second-line treatment. The main exclusion criteria were a switch to second-line treatment for intolerance or for low adherence to therapy. RESULTS: The main findings of this analysis are summarized in the table. Seventy-one pts meeting the inclusion/exclusion criteria were identified; the median age of pts at CML diagnosis was 46 (21-80) years. Sokal risk score was low, intermediate, and high in 24 (34%), 30 (42%), and 17 (24%) pts, respectively. First-line treatment was performed with nilotinib in 47 (66%) pts and dasatinib in 24 (34%) pts. According to the ELN 2020 recommendations, 51 (72%) pts fulfilled the criteria for "failure" and 20 (28%) pts those for "warning". BCR-ABL mutations were identified in 12 of 65 (18%) evaluable pts (T315I in 1 pt). Additional chromosomal abnormalities in Ph+ cells were identified in 6 of 54 (11%) evaluable pts. Second-line treatment was started after a median time of 16 (4-72) months, with ponatinib (40 pts, 56%), dasatinib (21 pts, 30%), nilotinib (7 pts, 10%), or bosutinib (3 pts, 4%). Median follow-up from start of second-line treatment was 25 (2-90) months. Best response to second-line treatment was MR2 in 18 (25%) pts and MR3 in 37 (51%) pts. Nineteen (27%) pts (13 for resistance and 6 for intolerance) switched to third-line treatment (ponatinib, 11 pts; nilotinib, 3 pts; dasatinib, 4 pts; imatinib, 1 pt), after a median time of 8 (1-72) months. Mutations were identified in 2 of 17 evaluable pts, and both patients harbored a T315I mutation. MR3 was reached by 9 (47%) of these pts. Lastly, 7 (10%) pts switched (6 for resistance and 1 for intolerance) to fourth-line treatment (asciminib, 4pts; dasatinib, 2 pts, nilotinib, 1 pt). Overall, 44 (62%) patients reached with sequential TKI treatments a MR3 (31/51 pts among "failures"; 13/20 among "warnings"). Allogeneic stem-cell transplantation (SCT) was performed in 7 (9.5%) pts (6 among "failures"), after a median time of 20 (15-60) months from CML diagnosis. Progression to advanced phase occurred in 2 (3%) pts; both pts previously met the ELN2020 "failure" criteria. Estimated 4-y PFS was 92.5%. Death occurred in 3 (4%) pts (1 after progression to blast phase, 2 for cardiovascular adverse events). Estimated 4-y OS was 93.7% CONCLUSION Our findings show that CP-CML patients not achieving an optimal response to frontline 2G-TKI therapy, despite a complex management, still have a favorable prognosis and survival due to the availability of both multiple TKI options and SCT. Figure Disclosures Gugliotta: Novartis: Honoraria; Incyte: Honoraria; Pfizer: Honoraria. Galimberti:Novartis: Speakers Bureau; Incyte: Honoraria. Abruzzese:Pfizer: Consultancy, Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees; Bms: Honoraria; Incyte: Consultancy, Membership on an entity's Board of Directors or advisory committees. Bocchia:CELGENE: Honoraria; Incyte: Honoraria. Castagnetti:Bristol Myers Squibb: Consultancy, Honoraria; Pfizer: Consultancy, Honoraria; Novartis: Consultancy, Honoraria; Incyte: Consultancy, Honoraria. Di Raimondo:Amgen, Takeda, Novartis: Honoraria; Janssen: Consultancy, Honoraria; Celgene: Consultancy, Honoraria; GILEAD, Incyte: Research Funding; GSK: Consultancy, Honoraria; Takeda: Consultancy, Honoraria; Amgen: Consultancy, Honoraria. Cavo:Jannsen, BMS, Celgene, Sanofi, GlaxoSmithKline, Takeda, Amgen, Oncopeptides, AbbVie, Karyopharm, Adaptive: Consultancy, Honoraria. Rosti:Bristol-Myers Squibb: Speakers Bureau; Incyte: Speakers Bureau; Novartis: Speakers Bureau; Pfizer: Research Funding, Speakers Bureau. Foà:Abbvie: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Roche: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Roche: Membership on an entity's Board of Directors or advisory committees; Novartis: Speakers Bureau; Incyte: Speakers Bureau. Saglio:Pfizer: Research Funding; Ariad: Research Funding; Roche: Research Funding; Incyte: Research Funding; Bristol-Myers Squibb: Research Funding; Novartis: Research Funding. Breccia:Abbvie: Consultancy; Pfizer: Consultancy, Honoraria; Incyte: Consultancy, Honoraria; Bristol-Myers Squibb/Celgene: Consultancy, Honoraria; Novartis: Consultancy, Honoraria.

Excellent outcomes of 2G-TKI therapy after imatinib failure in chronic phase CML patients.

Second-generation tyrosine kinase inhibitors (2G-TKIs) dasatinib and nilotinib produced historical rates of about 50% complete cytogenetic response (CCyR) and about 40% major molecular response (MMR) in chronic myeloid leukaemia (CML) patients failing imatinib. Direct comparisons between dasatinib and nilotinib are lacking, and few studies addressed the dynamics of deep molecular response (DMR) in a “real-life” setting.We retrospectively analyzed 163 patients receiving dasatinib (n = 95) or nilotinib (n = 68) as second-line therapy after imatinib. The two cohorts were comparable for disease's characteristics, although there was a higher rate of dasatinib use in imatinib-resistant and of nilotinib in intolerant patients.Overall, 75% patients not in CCyR and 60% patients not in MMR at 2G-TKI start attained this response. DMR was achieved by 61 patients (37.4%), with estimated rate of stable DMR at 5 years of 24%. After a median follow-up of 48 months, 60% of patients persisted on their second-line treatment. Rates and kinetics of cytogenetic and molecular responses, progression-free and overall survival were similar for dasatinib and nilotinib.In a “real-life” setting, dasatinib and nilotinib resulted equally effective and safe after imatinib failure, determining high rates of CCyR and MMR, and a significant chance of stable DMR, a prerequisite for treatment discontinuation.

Discontinuation of dasatinib or nilotinib in chronic myeloid leukemia: interim analysis of the STOP 2G-TKI study

AbstractSTOP second generation (2G)–tyrosine kinase inhibitor (TKI) is a multicenter observational study designed to evaluate 2G-TKI discontinuation in chronic myeloid leukemia (CML). Patients receiving first-line or subsequent dasatinib or nilotinib who stopped therapy after at least 3 years of TKI treatment and in molecular response 4.5 (MR4.5) with undetectable BCR-ABL1 transcripts for the 2 preceding years at least were eligible for inclusion. This interim analysis reports outcomes of 60 patients with a minimum follow-up of 12 months (median 47, range: 12-65). Twenty-six patients (43.3%) experienced a molecular relapse defined as the loss of a major molecular response (MMR). Relapses occurred after a median time of 4 months (range: 1-38). Cumulative incidences of molecular relapse by 12 and 48 months were 35% (95% confidence interval [CI], 24.79% to 49.41%) and 44.76% (95% CI, 33.35% to 59.91%), respectively. Treatment-free remission (TFR) rates at 12 and 48 months were 63.33% (95% CI, 51.14% to 75.53%) and 53.57% (95% CI, 40.49% to 66.65%), respectively. In univariate analysis, prior suboptimal response or TKI resistance was the only baseline factor associated with significantly worse outcome. A landmark analysis demonstrated that loss of MR4.5 3 months after stopping TKI was predictive of failure to maintain MMR later on. During the treatment-free phase, no progression toward advanced phase CML occurred, and all relapsing patients regained MMR and MR4.5 after restarting therapy. In conclusion, discontinuation of first-line or subsequent 2G-TKI yields promising TFR rates without safety concerns. Further research is encouraged to better define conditions that will offer patients the highest chance to remain free from 2G-TKI therapy.

In Elderly Patients with CML Second Generation TKIs Are Very Effective and Can be Given Long Term Particularly in the Absence of Comorbidities: A Single Center Experience

INTRODUCTIONSecond and third generation tyrosine kinase inhibitors (TKIs) are available for Philadelphia positive chronic myeloid leukemia (Ph+ CML) treatment, but though median age at diagnosis is 60-65 years, elderly patients are under-represented in clinical trials concerning 2G-TKIs and a very small number of papers has been published with series of CML patients > 65 years treated with 2G-TKIs or ponatinib. AIMwe have reviewed our single-center experience with 2G-TKIs in chronic-phase CML (CP-CML) patients > 65 years, in first or subsequent therapeutic lines. PATIENTS AND METHODSthe patients were 10 females and 13 males; CML diagnosis had been made between 1994 and 2015 at a median age of 67 years (61-77). According to Sokal score, 3 patients (13%) were classified as low, 15 (65%) as intermediate and 5 (22%) as high-risk respectively. B3a2 transcript was detected in 13 (56%), b2a2 in 10 (44%) cases.Overall, 30 therapies with 2G-TKIs were prescribed in 23 patients CP-CML > 65 years old, from 2007 to 2015. At 2G-TKI therapy start the median age was 68 years (65-79). Charlson Comorbidity Index (CCI) score was 0 in 11 patients, 1 in 4 patients, 2 in 4 patients, 3 in 3 patients and 4 in 1 patient.Thirteen of 23 patients received second-generation TKIs (2G-TKIs) up-front (6 nilotinib, 7 dasatinib), 10/23 patients as 2nd line therapy (6 nilotinib, 4 dasatinib) after imatinib failure (8/10) or intolerance (2/10), median time from imatinib start to 2G-TKIs being 18 months (9-120). Five of 23 patients needed a TKI as 3rd therapeutic line (4 dasatinib, 1 bosutinib), 1 patient also as 4th (ponatinib) and 5th line (bosutinib). RESULTSall 23 patients are alive after a median follow up of 45 months (12-259) from diagnosis; median follow up from the first 2G-TKI treatment is 36 months (12-110), in details 37 months (12-110) for patients that received 2G-TKIs up front and 34 months (12-70) for patients that received first 2G-TKI as second line therapy.Seventeen of 23 patients (74%) are still on 2G-TKI therapy, with a median treatment of 37 months (12-110) -table 1-. At the last visit 15/17 patients had MMR or best results (1 MR4.5, 9 MR4, 4 MR3).Six patients of 23 (26 %) stopped definitively 2G-TKI therapy, after a median treatment duration of 31 months (6-68) from the first 2G-TKI (table 2), in all cases for non-hematologic toxicity: 1 recurrent pleural effusion (grade 2), 1 geriatric syndrome, 1 carotid atherosclerotic disease, 1 PAOD, 1 vomiting (grade 3) and 1 pulmonary hypertension. At discontinuation, the disease response was MMR (2 patients), MR4 (3 patients), MR 4.5 (1 patient).Hematologic toxicity occurred during 2G-TKI treatment in 7/23 patients (30%), grade 1-2 in 4, grade 3-4 in 3. Sixteen of 23 (69%) patients experienced non-hematologic toxicity, grade 1-2 in 7 (30%) -5/7 pleural effusion-, and grade 3-4 in 9 (39%) -table 3-.There were no significant differences between patients still on therapy and patients that completely discontinued 2G-TKIs regarding Sokal score risk and b2a2/b3a2 transcripts. Conversely, CCI differed in these 2 categories, because CCI was > 1 in 5/6 (83%) of "discontinued" patients and in 7/17 (41%) of "ongoing" patients. Among the eleven patients with CCI = 0, only 1 discontinued 2G-TKI treatment. CONCLUSIONSOur experience shows that 2G-TKIs are very effective in elderly CP-CML, not only as first line therapy. Non-hematologic toxicity is high and it is the main reason for 2G-TKI discontinuation, that appears to be related to comorbidities. The vast majority of patients without comorbidities remain on 2G-TKI treatment long term. [Display omitted] [Display omitted] [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Real-Life Data and a Single Center Experience on the Efficacy and Toxicity Profile of Imatinib in the Treatment of Elderly Patients with Chronic Myeloid Leukemia

Background: Although it may vary between different registries, the median age of chronic myeloid leukemia (CML) at diagnosis is between 50-60 years, and approximately 40% of the patients (pts) are diagnosed after age 60 [Hoffmann et al. Leukemia. 2015;29(6):1336-43]. Tyrosinekinase inhibitors (TKIs) have revolutionized the treatment of CML and currently pts with CML may expect to live close to normal lifespan. So the number of elderly CML pts with various potentialcomorbidities started to increase, which then brings out the issues regarding TKI toxicities, medication adherence and responses to TKI treatment.Aim: The aim of this study was to evaluate the efficacy and safety ofimatinib treatment in the elderly population (pts equal to or older than 60 years) with CML and to compare these data with younger pts (pts < 60 years).Patients and Methods: Pts diagnosed and followed in our clinic with CML were enrolled in the study. Patient demographics, dose and duration ofimatinib therapy, disease risk scores, cytogenetic and molecular responses,comorbidities, adverse events (AEs), follow-up durations and outcomes were evaluated from files of the pts, retrospectively. TheCharlsoncomorbidity index (CCI) of each patient was calculated as stated before [Breccia et al.Haematologica. 2011;96(10):1457-61].Results: The patient cohort was consisted of 158 pts with a median age of 44 years (range, 18 - 83 years). Group A consisted of thirty-three pts who were equal to or older than 60 years (Fig. 1), and there were 125 pts (Group B) who were < 60 years of age (Table 1). The two groups were balanced regarding gender, disease stage, treatments prior to TKI therapy, and the starting dose ofimatinib. There were more pts with intermediate and highSokal risk scores in Group A than that of Group B (p<0.001). Pts in Group A had significantly morecomorbidities (p<0.001) and higher CCI scores (p<0.001) than pts who were < 60 years of age (Table 1). Median time ofimatinib exposure (p=0.001) and follow-up durations (p<0.001) were significantly longer in Group B than those of Group A. There were significantly more hematologicAEs among pts in Group A than pts in Group B (24% vs. 7%, p=0.005). Although not statistically significant, non-hematologicAEs were more common in GroupA (18% vs. 7%, p=0.056), and the rates ofimatinib dose reduction due toAEs were significantly higher in Group A than Group B (33% vs. 9%, p<0.001). Cumulative complete cytogenetic (CCyR) and major molecular (MMR) response rates and the percentage of pts who switched to second-generationTKIs (2GTKIs) were similar in both groups (Table 1). Event-free survival (EFS) rates were comparable (Fig. 2A), however overall survival (OS) rate was significantly higher in Group B (Fig. 2B) (p<0.001). There were 7 pts in both groups who died during the follow-up, but five and 2 pts died due to non-CML related causes in Groups A and B, respectively. OS rates were similar in both groups when non-CML related deaths were excluded (Fig. 2C).Discussion: TKI therapy is relatively safe in elderly pts with CML, and cytogenetic and molecular responses are comparable with that observed in younger pts. In our institute, where pts are followed in a dedicated outpatient CML clinic, cytogenetic and molecular responses were similar in both elderly and younger pts leading to similar percentages of pts who were switched to 2GTKI therapy in both groups. Comorbidities can be problematic in elderly pts in whom CML and TKI relatedAEs are more common. However proper management of theseAEs including careful follow-up and timely TKI dose reductions may lead to successful outcomes. Inferior OS rates were observed in elderly pts with CML, but OS rates were similar in both groups when non-CML related deaths were excluded. [Display omitted] [Display omitted] [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Somatic Mutations in Epigenetic Modifiers Identified Using Next Generation Sequencing (NGS) in Diagnostic Samples of CML-CP Can Predict Poor Outcome on Imatinib Which Is Abrogated By Frontline 2G-TKI Therapy

Background: While chronic myeloid leukaemia (CML) originates from a single genetic aberration (BCR-ABL1) remarkably heterogeneity characterises treatment response and outcome. Most CML patients respond well to tyrosine kinase inhibitors (TKI), particularly 2nd generation (2G) TKI but a significant minority shows resistance and a proportion experience progression. At diagnosis there are currently no biomarkers for patients at higher risk of progression who could be treated with more effective treatment or be selected for BMT at an early stage of therapy. Such biomarkers may also provide useful prognostic information in addition to the most valid biomarker to date, the BCR-ABL1 IS ratio during the first 3-6-12 months of TKI therapy.Aims: The aim of our study is to analyse a panel of mutations in epigenetic modifiers in pre-treatment CML-CP using Ion Torrent next-generation sequencing (IONT-NGS) to assess the prognostic value of potential mutations as novel biomarkers of response to 1st and 2G TKI and risk of progression to advanced phase disease.Methods: 100 samples from untreated patients with newly diagnosed CML-CP were included in the study, 62 from patients treated frontline with imatinib (IM) and 38 with a 2G-TKI (31 dasatinib, 4 nilotinib, 3 bosutinib). The patients were classified as TKI responders (R) (34 IM, 22 2G-TKI) or non-responders (NR) (28 IM, 16 2G-TKI) based on BCR-ABL1 IS ratio at 3 months. DNA was extracted from CD34+ cells isolated from diagnostic samples, while DNA from T cells was used as constitutional non-leukemic control to exclude confounding germline mutations. Samples from healthy donors (n=14) and CML blast crisis (BC) (n=5) patients were used as negative and positive controls, respectively. We used a custom panel covering the coding region of 71 epigenetic enzymes. After sequencing data processing was performed excluding variants of low quality, common in the general population with minor allele frequency (maf) >1% or present in the healthy controls, we analysed the genomic data and integrated them with annotated clinical data.Results: After using a variant reduction pipeline, 164 non-synonymous variants that affected protein function were identified: 52 somatic and 112 germline. The somatic mutations (including missense, nonsense, frameshift insertions and splice site variants) were confined to 30 genes, with ASXL1, IKZF1, CREBBP beingthe most frequently mutated (n=9, 7 and 4 respectively). The mutations were detected in 34/100 (34%) CML-CP patients (19/62 IM and 15/38 2G-TKI), in higher proportion in NR (19/44, 43%) compared to R (15/56, 27%; p=0.027). We next correlated the presence of mutations with overall survival (OS), TKI failure free survival (TFFS) and progression free survival (PFS). IM patients carrying somatic mutations demonstrated a poorer response to IM [HR=2.1 (1-4.4 95% CI), p=0.05] and were more likely to progress to advanced phase [HR=3.1 (1-9.4 95% CI), p=0.03] (Figure 1). Nonsense mutations in particular (in ASXL1, IKZF1, DNMT3A, EP300) were found in 4 IM NR vs 1 R and their presence led to poor OS [HR= 6.1 (1.6-23 95% CI), p=0.002] and PFS [HR= 5.4 (1.4-21 95% CI), p=0.006]. As these were observed in 5 patients, further testing is required to corroborate this initial observation. Multivariate analysis revealed that both increased Sokal score and occurrence of somatic mutations negatively influenced outcome: somatic mutations detected in 6/24 low and in 8/13 high Sokal IM patients were associated with worse OS and PFS compared to unmutated patients with the same Sokal score. Among 38 patients treated with 2G-TKI, neither somatic mutations (including nonsense variants) nor combination of somatic mutations with Sokal score had any influence on OS, TFFS, PFS, neither did the presence of germline mutations in either IM or 2G-TKI patients.Summary/Conclusion: Somatic mutations identified using IONT-NGS on 71 epigenetic modifiers potentially predict 1st generation (IM) patient poor survival, drug failure and progression to advance phase disease. However, the more effective therapeutic effect of 2G-TKI seems to overcome the poor prognostic influence of such mutations though further validation on larger cohort of patients may be required to validate preliminary data. Our results suggest that occurrence of somatic mutations at diagnosis have the potential to identify patients who would benefit from upfront treatment with 2G-TKI. [Display omitted] DisclosuresApperley:Incyte: Speakers Bureau; Novartis: Honoraria, Speakers Bureau; Ariad: Honoraria, Speakers Bureau; Pfizer: Honoraria, Speakers Bureau; Bristol Myers Squibb: Honoraria, Speakers Bureau.

Next-generation sequencing for sensitive detection of BCR-ABL1 mutations relevant to tyrosine kinase inhibitor choice in imatinib-resistant patients.

In chronic myeloid leukemia (CML) and Philadelphia-positive (Ph+) acute lymphoblastic leukemia (ALL) patients who fail imatinib treatment, BCR-ABL1 mutation profiling by Sanger sequencing (SS) is recommended before changing therapy since detection of specific mutations influences second-generation tyrosine kinase inhibitor (2GTKI) choice. We aimed to assess i) in how many patients who relapse on second-line 2GTKI therapy next generation sequencing (NGS) may track resistant mutations back to the sample collected at the time of imatinib resistance, before 2GTKI start (switchover sample) and ii) whether low level mutations identified by NGS always undergo clonal expansion. To this purpose, we used NGS to retrospectively analyze 60 imatinib-resistant patients (CML, n = 45; Ph+ ALL, n = 15) who had failed second-line 2GTKI therapy and had acquired BCR-ABL1 mutations (Group 1) and 25 imatinib-resistant patients (CML, n = 21; Ph+ ALL, n = 4) who had responded to second-line 2GTKI therapy, for comparison (Group 2). NGS uncovered that in 26 (43%) patients in Group 1, the 2GTKI-resistant mutations that triggered relapse were already detectable at low levels in the switchover sample (median mutation burden, 5%; range 1.1%–18.4%). Importantly, none of the low level mutations detected by NGS in switchover samples failed to expand whenever the patient received the 2GTKI to whom they were insensitive. In contrast, no low level mutation that was resistant to the 2GTKI the patients subsequently received was detected in the switchover samples from Group 2. NGS at the time of imatinib failure reliably identifies clinically relevant mutations, thus enabling a more effective therapeutic tailoring.