The Impact of EUTOS Long-Term Survival (ELTS) Score on Predicting Progression and Survival Among Turkish Patients with Chronic Myeloid Leukemia

Introduction and Objectives: For patients (pts) with chronic myeloid leukemia in chronic phase (CML-CP), four baseline prognostic scores are commonly used including the Sokal score and the most recently introduced EUTOS long-term survival (ELTS) score. The ELTS score was shown to be superior to the Sokal score for predicting survival. The aim of the study is to evaluate the value of ELTS score on predicting disease progression and survival in Turkish pts with CML-CP. Material and Method: Demographic, laboratory and clinical features, disease responses to tyrosine kinase inhibitor (TKI) therapy and survival of CML-CP pts, who received upfront imatinib (IM) between 2003 and 2018 were analyzed retrospectively. Treatment responses were reevaluated according to European LeukemiaNet 2013 recommendations. Risk groups analysis, discrimination and hazard ratios (HRs) were evaluated with Cox regression and Kaplan-Meier survival analysis. Receiver operating characteristic (ROC) analysis was performed to examine the effects of scores on predicting overall survival (OS) and progression-free survival (PFS). Results: A total of 185 pts were included, of which 103 (55.7%) were male and median age was 47 years (range, 16 - 81 years) (Table 1). The percentages of pts with low-, intermediate-, and high-risk ELTS scores were 60.5%, 25.9%, and 13.5%, respectively. For the Sokal score, these percentages were 37.3%, 40.5%, and 22.2% respectively. For Sokal high-risk pts, only 46.3% were classified as high-risk according to the ELTS score. Similarly, 44% of pts with intermediate Sokal risk had low-risk ELTS score (Fig. 1). Seventy-seven pts (41.6%) had at least one comorbidity, and the most common comorbidities were hypertension (21.6%), diabetes mellitus (13%), and ischemic heart disease (12.4%) (Table 1). The median durations of IM therapy and follow-up were 2728 (range, 14 - 6320 days) and 3473 (range, 71 - 6320 days) days, respectively. Complete hematologic and early molecular (BCR-ABL1 IS <10% at 3 months) responses at 3 months were 95.6% and 75.9%, respectively. Complete cytogenetic and major molecular response rates at 6 and 12 months were 72.3% and 86.1% and 45.4% and 54%, respectively. Thirty-five pts (18.9%) switched to second-generation TKI therapy and 6 pts (3.2%) progressed to advanced-phase disease during the follow-up (Table 1). For PFS, with reference to the low-risk Sokal score, the HR of high-risk groups was 9.301 (95% CI: 1.086-79.656, p=0.042) (Fig. 2A). Similarly, with reference to the low-risk ELTS score, the HR of intermediate- and high-risk groups were 4.744 (95% CI: 0.43-52.314, p=0.204) and 14.642 (95% CI: 1.523-140.791, p=0.020) (Fig. 2B). Regarding OS, with reference to the low-risk Sokal score, the HR of the intermediate- and high-risk groups were 1.835 (95% CI: 0.564-5.964, p=0.313) and 6.412 (95% CI: 2.11-19.489, p=0.001), respectively (Fig. 2C). With reference to the low-risk ELTS score, the HR of the intermediate- and high-risk groups were, 3.263 (95% CI: 1.242-8.576, p=0.016) and 7.258 (95% CI: 2.762-19.074, p<0.001) respectively (Fig. 2D). In the ROC analysis, the ELTS score was superior than the Sokal risk score for both predicting PFS (AUC=0.820 vs. AUC=0.818) and OS (AUC=0.762 vs. AUC=0.744). During the follow-up, 27 (14.6%) pts died, of which 6 died due to CML progression and causes of death were unrelated to CML in 21. Conclusion: In our study, we showed that the ELTS score could successfully predict high-risk pts compatible with the literature. With higher hazard ratios and better risk group stratifications, the ELTS score outperformed the Sokal score. The ELTS score can help clinicians to better discriminate poor prognostic pts and can promote optimal treatment strategies for these pts with potentially worse prognosis. Figure 1 Figure 1. Disclosures No relevant conflicts of interest to declare.

Prognostic Factors for Overall Survival In Chronic Myeloid Leukemia Patients: A Multicentric Cohort Study by the Italian CML GIMEMA Network

An observational prospective study was conducted by the CML Italian network to analyze the role of baseline patient characteristics and first line treatments on overall survival and CML-related mortality in 1206 newly diagnosed CML patients, 608 treated with imatinib (IMA) and 598 with 2nd generation tyrosine kinase inhibitors (2GTKI). IMA-treated patients were much older (median age 69 years, IQR 58-77) than the 2GTKI group (52, IQR 41-63) and had more comorbidities. Estimated 4-year overall survival of the entire cohort was 89% (95%CI 85.9-91.4). Overall, 73 patients (6.1%) died: 17 (2.8%) in the 2GTKI vs 56 (9.2%) in the IMA cohort (adjusted HR=0.50; 95% CI=0.26-0.94), but no differences were detected for CML-related mortality (10 (1.7%) vs 11 (1.8%) in the 2GTKIs vs IMA cohort (sHR=1.61; 0.52-4.96). The ELTS score was associated to CML mortality (high risk vs low, HR=9.67; 95%CI 2.94-31.74; p<0.001), while age (per year, HR=1.03; 95%CI 1.00-1.06; p=0.064), CCI (4-5 vs 2, HR=5.22; 95%CI 2.56-10.65; p<0.001), ELTS score (high risk vs low, HR=3.11; 95%CI 1.52-6.35, p=0.002) and 2GTKI vs IMA (HR=0.26; 95%CI 0.10-0.65, p=0.004) were associated to an increased risk of non-related CML mortality. The ELTS score showed a better discriminant ability than the Sokal score in all comparisons.

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.

Plasma imatinib levels and ABCB1 polymorphism influences early molecular response and failure-free survival in newly diagnosed chronic phase CML patients

Achieving early molecular response (EMR) has been shown to be associated with better event free survival in patients with chronic phase chronic myeloid leukemia (CP-CML) on Imatinib therapy. We prospectively evaluated the factors influencing the 2-year failure free survival (FFS) and EMR to imatinib therapy in these patients including day29 plasma Imatinib levels, genetic variants and the gene expression of target genes in imatinib transport and biotransformation. Patients with low and intermediate Sokal score had better 2-year FFS compared to those with high Sokal Score (p = 0.02). Patients carrying ABCB1-C1236T variants had high day29 plasma imatinib levels (P = 0.005), increased EMR at 3 months (P = 0.044) and a better 2 year FFS (P = 0.003) when compared to those with wild type genotype. This translates to patients with lower ABCB1 mRNA expression having a significantly higher intracellular imatinib levels (P = 0.029). Higher day29 plasma imatinib levels was found to be strongly associated with patients achieving EMR at 3 months (P = 0.022), MMR at 12 months (P = 0.041) which essentially resulted in better 2-year FFS (p = 0.05). Also, patients who achieved EMR at 3 months, 6 months and MMR at 12 months had better FFS when compared to those who did not. This study suggests the incorporation of these variables in to the imatinib dosing algorithm as predictive biomarkers of response to Imatinib therapy.

Real World Efficacy Evaluation of Branded and Copy Imatinib in Chronic Myeloid Leukemia: A Retrospective Multicentric Study from Argentina

Background: Data on the safety and efficacy of copy drugs is usually unavailable. Imatinib mesylate is used to treat chronic myeloid leukemia (CML) patients in Argentina since 2002. During the last decade more than ten different imatinib copies are marketed by the different health-care systems in the country, usually for cost issues. In spite of the undoubted benefit of this tyrosine-kinase inhibitor indication in CML, there is no solid evidence that supports copy drug equivalent outcomes for this patient population. Aim: To compare the clinical presentation, treatment response and outcome of a chronic phase (CP) CML patient cohort treated with branded and copy imatinib in the real-life setting. Methods: Multicentric, retrospective trial based on data obtained from medical charts of adult CP CML patients treated with imatinib in 9 centers in Argentina from 2002 to 2020.We analyzed demographic characteristics and clinical characteristics described for branded and copy imatinib treated cohorts. Frequency of complete cytogenetic response (CCyR) at 12 months, Major molecular response or better(≥MMR) at 12, 18 and 24 months and overall MR4.0, MR4.5 and deep molecular response (MR4.0 +MR4.5 IS) were analyzed. Event was defined as failure, progression or CML related death. Kaplan Meier comparison of event free, progression free and overall survival. Statistics: IBM SPSS version 1. Results: A total of 568 CP CML adult patients (pt) treated with imatinib were included. Mean age at diagnosis: 45.7 years (range 18 - 85). Male 55.6% (316/568). Sokal Score was recorded in 471 pt: 57% (269/471) low, 26% (122/471) intermediate and 17% (80/471) high-risk. Median follow-up 107 months (RIQ: 36-149). Branded imatinib treatment 330 (58%) and imatinib copies 238 (42%). For branded and copy imatinib cohorts mean age 46,1 (18-85) and 45.3(18-80), male 53% (175/330) and 59% (141/238), median follow up 102 (RIQ 101-130) and 61 (RIQ 62-146) respectively. Sokal score low 58% (164/284) and 56% (105/187), intermediate 27% (77/284) and 24% (45/187) and high 15% (43/284) and19% (37/187). Frequency of CCyR at 12 months 71% (67/94) and 69% (41/59), ≥MMR at 12 months 57% (79/138) and 43% (39/89), ≥MMR 18m 66 % (61/92) and 71% (43/60), ≥MMR 24m 65% (96/147) and 79% (58/73). Overall MR4, MR 4.5 and Deep MR with branded imatinib 62.4% (186/298), 42% (118/276) and 63% (189/300), compared to 45(97/214), 24% (50/207) and 46% (99/215) with copies. Difference in evaluation throughout the treatment periods with loss of data did not allow response rate statistical comparison in predetermined timepoints. Kaplan Meier Event free survival median 229 months vs 75 months p 0.001, Progression free survival mean 318 months vs 208 pt 0.034 and Overall Survival mean 275 months vs 206 months for branded and copy imatinib respectively. Discussion: Several case reports have shown poor outcomes in patients treated with imatinib copy drugs, including loss of responses previously attained with branded imatinib. This study reports data from a large cohort of CP CML patients treated in daily practice during a long period of time. Treatment results at determined timepoints is comparable. Although management and treatment decisions were performed in different time periods, results show different outcomes in EFS and PFS between patients treated with branded vs copy imatinib. Overall survival in both cohorts is comparable. As studies assesing the safety and efficacy of the copy drugs compared with branded imatinib will hardly be performed this evidence calls for careful attention and strict follow up measures when managing CML patients with copy imatinib. Figure Disclosures Varela: Novartis: Consultancy, Speakers Bureau. Pavlovsky:Pint Pharma: Speakers Bureau; Pfizer: Speakers Bureau; BMS: Speakers Bureau; Novartis: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Freitas:Pfizer: Consultancy, Other: Advisory Board. Pavlovsky:Varifarma: Speakers Bureau; Astra Zeneca: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Janssen: Membership on an entity's Board of Directors or advisory committees, Other: travel grants, Speakers Bureau; Abbvie: Membership on an entity's Board of Directors or advisory committees, Other: Travel grants, Speakers Bureau. Moiraghi:Novartis: Speakers Bureau; BMS: Speakers Bureau.

CML: Der Weg zur optimalen Therapieselektion

Prognostic scores support clinicians in selecting risk-adjusted treatments and in comparatively assessing different results. For patients with chronic-phase chronic myeloid leukemia (CML), four baseline prognostic scores are commonly used. Our aim was to compare the prognostic performance of the scores and to arrive at an evidence-based score recommendation. In 2949 patients not involved in any score development, higher hazard ratios and concordance indices in any comparison demonstrated the best discrimination of long-term survival with the ELTS score. In a second step, of 5154 patients analyzed to investigate risk group classification differences, 23% (n = 1197) were allocated to high-risk by the Sokal score. Of the 1197 Sokal high-risk patients, 56% were non-high-risk according to the ELTS score and had a significantly more favorable long-term survival prognosis than the 526 high-risk patients according to both scores. The Sokal score identified too many patients as high-risk and relatively few (40%) as low-risk (versus 60% with the ELTS score). Inappropriate risk classification jeopardizes optimal treatment selection. The ELTS score outperformed the Sokal score, the Euro, and the EUTOS score regarding risk group discrimination. The recent recommendation of the European LeukemiaNet for preferred use of the ELTS score was supported with significant statistical evidence.

Enestpath Leukemic Stem Cell (LSC) Sub-Study: Analyzing Characteristics of LSC-Positive Patients and Impact of Switch from Imatinib to Nilotinib Therapy on LSCs in Patients with Chronic Myeloid Leukemia

Background Treatment-free remission (TFR) in patients with chronic myeloid leukemia (CML), who achieve a sustained and deep molecular response (DMR, MR4 or MR4.5) after treatment with BCR-ABL1 tyrosine kinase inhibitors (TKIs), is possible after TKI discontinuation (Rea and Cayuela. 2018). Nilotinib has been shown to elicit deeper and faster molecular responses compared to imatinib. More than 50% of patients who responded to imatinib, but did not achieve a DMR, achieved a DMR 1 year after they switched to nilotinib (Hughes et al. 2017). On attempting TFR, about 50% of patients lose response early and relapse (Mahon et al. 2019). The reason for this loss of response after achieving sustained DMR in patients has been attributed to residual and quiescent LSCs (Houshmand, et al. 2019). LSC for CML arises from the transformation of a hematopoietic stem cell through a t(9;22) translocation, leading to the Philadelphia chromosome [Ph1], and is characterized by the presence of the unregulated tyrosine kinase activity of the chimeric BCR-ABL1 protein together with specific surface antigens including CD26 and/or other aberrant markers (Bocchia, et al. 2018). The ENESTPath study is designed to evaluate the impact of duration of 24 or 36 months (mos) of consolidation treatment with nilotinib after switching from imatinib, on the rate of TFR. The LSC sub-study was designed to evaluate the correlation between duration of nilotinib therapy and LSCs. This interim analysis of the LSC sub-study presents preliminary data on characteristics of LSC-positive patients and their response after 24 mos of nilotinib therapy. Objectives To assess factors impacting LSCs and the effect of nilotinib therapy in patients with CML who switched from imatinib to nilotinib. Methods Patients from the ENESTPath study who switched from imatinib received 24 mos of nilotinib therapy (12 mos of induction and consolidation therapy, each). Patients who achieved stable MR4 (4/5 preceding quarterly real-time quantitative polymerase chain reaction [RT-PCR] assessments were ≥MR4 and last assessment was ≥MR4) at the end of the consolidation phase were randomized 1:1 to receive either an additional 1 year of nilotinib treatment or to start TFR, while those without stable MR4 were not randomized (NR), and followed-up until end of the study (5 years after baseline visit). For the current analysis, bone marrow samples collected at screening and at 24 mos were evaluated for the presence of Ph+ on fluorescence-activated cell sorting-purified CD34+CD38-/+ cells by fluorescence in situ hybridization and/or RT-PCR techniques. Results Of the 60 patients enrolled in the sub-study, 34 were randomized, 25 were NR, and 1 had protocol deviation (not included in the analysis). Overall, the mean age of the patients was 49.4 years. All patients had been previously treated with imatinib for a median duration of 59.7 mos. When analyzed for LSCs by RT-PCR or histone (HIS) at baseline, 10 patients were found to be positive, 23 were negative, 25 patients had data missing, and 1 was not evaluable. Sokal score categories and duration of prior imatinib therapy for LSC-positive and negative patients at baseline are presented in Table 1. More patients with low Sokal risk and longer duration of prior imatinib therapy (≥ 5 years) were negative for LSCs at baseline (Table 1). After treatment with nilotinib, the number of patients with Ph+ among CD34+CD38-, CD34+CD38+, and CD34+CD38-/+ LSCs was lower at 24 mos compared to baseline, except for aberrant CD34+ cells in the NR group (Figure 1). A decrease in the percentage of CD34+/CD38+ and immunophenotypically aberrant CD34+/- cells was observed for most of the patients analyzed at baseline and at 24 mos by HIS or RT-PCR. Overall, 11 and 10 patients in the randomized and NR groups, respectively, had ≥1 dose reduction/interruptions; adverse events led to dose reduction/interruptions in 9 patients each, in both arms. Conclusion This analysis indicates that treatment of CML patients with nilotinib after switching from imatinib may play a role in the reduction of LSCs over time. As the number of patients with available Sokal score at baseline and prior imatinib exposure was low, meaningful conclusions cannot be drawn, and further investigations are needed. Results of patients attempting TFR are awaited, and it would be interesting to analyze the correlation between the LSC count and rate of TFR in the final analysis of the sub-study. Disclosures Sanchez-Guijo: BMS: Consultancy, Honoraria; Incyte: Consultancy, Honoraria; Novartis: Consultancy, Honoraria, Research Funding; Pfizer: Consultancy, Honoraria; Gilead: Consultancy, Honoraria; Amgen: Honoraria; Roche: Honoraria. Plata:Novartis: Consultancy, Speakers Bureau; Takeda: Consultancy, Speakers Bureau; Sanofi: Consultancy, Speakers Bureau; Amgen: Consultancy, Speakers Bureau. Crugnola:Novartis: Honoraria; Incyte: Honoraria. Caocci:Novartis: Honoraria; Celgene: Honoraria. Oakervee:Novartis: Honoraria; Bristol Myers-Squibb: Honoraria; Pfizer: Honoraria. Jedrzejczak:Amgen: Consultancy; Takeda: Consultancy; Novartis: Research Funding; Amgen: Other: Travel support for hematology meetings (ASH, EBMT, EHA) ; Celgene: Other: Travel support for hematology meetings (ASH, EBMT, EHA); Roche: Other: Travel support for hematology meetings (ASH, EBMT, EHA). Kiani:Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau. Supekar:Novartis: Employment. Ferreira:Novartis: Employment. Shah:Novartis: Other: Service Provider. Steegmann:BMS: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Incyte: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Pfizer: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Baccarani:Novartis: Consultancy, Speakers Bureau; Incyte: Consultancy, Speakers Bureau; Takeda: Consultancy.