Abstract: Isocitrate dehydrogenase 1 (IDH1) mutations are associated with improved survival in gliomas. Depending on the IDH1 status, TERT promoter mutations affect prognosis. IDH1 mutations are associated with alpha-thalassemia/mental retardation syndrome X-linked (ATRX) mutations and alternative lengthening of telomeres (ALT), suggesting an interaction between IDH1 and telomeres. However, little is known how IDH1 mutations affect telomere maintenance. Methods We analyzed cell-specific telomere length (CS-TL) on a single cell level in 46 astrocytoma samples (WHO II-IV) by modified immune-quantitative fluorescence in situ hybridization, using endothelial cells as internal reference. In the same samples, we determined IDH1/TERT promoter mutation status and ATRX expression. The interaction of IDH1 R132H mutation and CS-TL was studied in vitro using an IDH1 R132H doxycycline-inducible glioma cell line system. Results Virtually all ALT positive astrocytomas had normal TERT promoter and lacked ATRX expression. Further, all ALT positive samples had IDH1 R132H mutations, resulting in a significantly longer CS-TL of IDH1 R132H gliomas, when compared to their wildtype counterparts. Conversely, TERT promotor mutations were associated with IDH wildtype , ATRX expression, lack of ALT and short CS-TL. ALT, TERT promoter mutations, and CS-TL remained without prognostic significance, when correcting for IDH1 status. In vitro, overexpression of IDH R132H in the glioma cell line LN319 resulted in downregulation of ATRX and rapid TERT-independent telomere lengthening consistent with ALT. Conclusion ALT is the major telomere maintenance mechanism in IDH R132H mutated astrocytomas, while TERT promoter mutations were associated with IDH wildtype glioma. IDH1 R132H downregulates ATRX expression in vitro resulting in ALT, which may contribute to the strong association of IDH1 R132H mutations, ATRX loss, and ALT.

Abstract: Higher doses of cytarabine appear to improve long-term outcome in acute myeloid leukemia (AML), in particular for younger patients. To this end, the optimal dosage of single-agent cytarabine in consolidation therapy remains elusive. Here, we assessed the impact of different dosages of cytarabine consolidation after 7 + 3 induction on outcome in a large real-world data set from the German Study Alliance Leukemia-Acute Myeloid Leukemia (SAL-AML) registry. Methods Patients between 18 and 64 years of age, registered between April 2005 and September 2020, who attained complete remission after intensive induction and received at least one consolidation cycle with intermediate (IDAC) or high-dose cytarabine (HiDAC) were selected. To account for differences in patient and disease characteristics between both groups, the average treatment effect was estimated by propensity score weighting. Results Six-hundred-forty-two patients received HiDAC consolidation with median dosage of 17.6 (IQR (interquartile range), 16.5–18.0) g/m 2 for a median number of 3 cycles (IQR, 2–3), whereas 178 patients received IDAC consolidation with 5.9 (IQR, 5.7–8.6) g/m 2 for a median of 2 cycles (IQR, 1–3). Both groups differed significantly in some important characteristics (age, sex, cytogenetic risk group, ECOG performance status, disease status, HCT-CI, number of induction cycles). After propensity score weighting for differences in patient and disease characteristics, relapse-free survival after 2 years was comparable between HiDAC-treated (55.3%) and IDAC-treated (55.6%) patients (HR = 0.935, p  = 0.69). Moreover, no significant differences in overall survival were observed after 2 years (84.7 vs. 80.6%, HR = 1.101, p  = 0.65). Notably, more patients treated with IDAC received allogeneic hematopoietic cell transplantation in first remission (37.6 vs. 19.8%, p   〈  0.001). Censoring for allogeneic hematopoietic cell transplantation in first remission revealed no significant survival difference with regard to cytarabine dosage. Considering only of European LeukemiaNet (ELN) favorable-risk AML patients, there was no significant difference in outcome. Of note, significantly more patients treated with HiDAC suffered from ≥ 3 CTCAE infectious complications (56.7 [95%-CI 52.8–60.6%] vs. 44.1% [95%-CI 36.6–51.7%] ; p  = 0,004). The rate of other ≥ 3 CTCAE non-hematological toxicities and secondary malignancies was comparable in both treatment groups. Conclusions This retrospective analysis suggests no significant benefit of high-dose cytarabine compared to intermediate dosages in consolidation for AML patients under 65 years of age, independent of ELN risk group. Trial registration NCT03188874.

Abstract: In fit patients with newly diagnosed acute myeloid leukemia (AML), immediate treatment start is recommended due to the poor prognosis of untreated acute leukemia. We explored the relationship between time from diagnosis to treatment start (TDT) and prognosis in a large real-world data set from the German Study Alliance Leukemia–Acute Myeloid Leukemia (SAL-AML) registry. All registered non–acute promyelocytic leukemia patients with intensive induction treatment and a minimum 12 months of follow-up were selected (n = 2263). We analyzed influence of TDT on remission, early death, and overall survival (OS) in univariable analyses for each day of treatment delay, in groups of 0 to 5, 6 to 10, 11 to 15, and & gt;15 days of TDT, adjusted for influence of established prognostic variables on outcomes. Median TDT was 3 days (interquartile range, 2-7). Unadjusted 2-year OS rates, stratified by TDT of 0 to 5, 6 to 10, 11 to 15, and & gt;15 days, were 51%, 48%, 44%, and 50% (P = .211). In multivariable Cox regression analysis accounting for established prognostic variables, the TDT hazard ratio as a continuous variable was 1.00 (P = .617). In OS analyses, separately stratified for age ≤60 and & gt;60 years and for high vs lower initial white blood cell count, no significant differences between TDT groups were observed. Our study suggests that TDT is not related to survival. As stratification in intensive first-line AML treatment evolves, TDT data suggest that it may be a feasible approach to wait for genetic and other laboratory test results so that clinically stable patients are assigned the best available treatment option. This trial was registered at www.clinicaltrials.gov as #NCT03188874.

Abstract: Introduction: Tyrosine kinase inhibitor therapy has been associated with cardiovascular (CV) events. BOS is approved for patients (pts) with newly diagnosed Philadelphia chromosome-positive (Ph+) chronic phase (CP) CML and Ph+ CML resistant/intolerant to prior therapy. We analyzed cardiac, vascular and hypertension treatment-emergent adverse events (TEAEs) in pts with newly diagnosed CP CML receiving BOS or IMA after 5 yrs follow-up in BFORE. Methods: In the open-label, phase 3 BFORE trial (NCT02130557), 536 pts with newly diagnosed CP CML were randomized 1:1 to receive first-line 400 mg once-daily BOS (n=268) or IMA (n=268; 3 untreated). The current analysis included all pts who received ≥1 dose of study drug. TEAEs were monitored from first dose of study drug until 28 d after last dose; monitoring of non-serious adverse events (AE) ended at the start of a new cancer treatment. Prespecified MedDRA terms (cardiac, n=133; vascular, n=502) comprised clusters of investigator-assessed TEAEs (Table). Multivariable proportional subdistribution hazard models predicting time to first TEAE included treatment group; baseline demographic information; history of cardiac events, vascular events, hypertension, diabetes, hyperlipidemia, and tobacco use; as well as hypertension, cardiac (for vascular model) and vascular (for cardiac model) TEAEs. CI excluding 1 was considered predictive of outcome. This analysis was based on 17-Apr-20 last pt last visit (12-Jun-20 database lock), 5 y (240 wks) after last enrolled pt. Results: At study completion, 59.7% of BOS pts and 58.1% of IMA pts were still on treatment. Median duration of treatment was 55 mo for pts receiving BOS or IMA; respective median (range) dose intensity was 393.6 (39-583) vs 400.0 (189-765) mg/d. In the BOS vs IMA arm, 57.8% vs 56.2% of pts had ≥1 CV risk factor at baseline; 20.9% vs 17.7% had ≥3 risk factors, respectively. The most common risk factors were a history of hypertension (BOS, 34.0%; IMA, 30.6%), BMI & gt;30 (BOS, 23.1%; IMA, 21.9%), age ≥65 y (BOS, 19.8%; IMA, 17.4%), and history of hyperlipidemia (BOS, 16.8%; IMA, 18.9%). Rates of cardiac, vascular and hypertension TEAEs; serious adverse events (AEs); AEs leading to treatment withdrawal and drug-related TEAEs (per investigator) were low in both arms (Table). Exposure-adjusted rates of cardiac, vascular and hypertension TEAEs were similar between arms (Table). Risk factors for cardiac TEAEs (HR; 95% CI) were age in years (1.04 [1.02-1.07]), race other than Asian or black compared to white ( & lt;0.01 [ & lt;0.01- & lt;0.01]), a history of tobacco use (6.94 [1.89-25.40] ) and cardiac events (3.59 [1.68-7.65]), hypertension (3.07 [1.20-7.84] ) and vascular TEAEs (5.27 [1.53-18.18]). Risk factors for vascular TEAEs (HR [95% CI] ) were black race compared to white ( & lt;0.01 [ & lt;0.01- & lt;0.01]), a history of vascular events (4.65 [1.81-11.97] ) and cardiac TEAEs (7.73 [2.31-25.84]). In multivariable analyses, treatment group was not predictive of time to initial cardiac (HR 0.87 [95% CI 0.45-1.70] ) or vascular (HR 2.17 [95% CI 0.94-45.04) TEAEs. The most common cardiac, vascular, and hypertension TEAEs, respectively, were sinus bradycardia (2.2%), angina pectoris (3.0%) and hypertension (9.7%) with BOS vs electrocardiogram QT prolongation (3.8%), peripheral coldness (1.1%) and hypertension (10.9%) with IMA. One grade 5 cardiac (acute cardiac failure) and one vascular (myocardial ischemia) TEAE were reported with BOS, and one vascular (cerebrovascular accident) TEAE with IMA; none were considered related to study drug. Successful treatment rechallenge was achieved in the majority of pts with dose interruptions due to cardiac (BOS, 85.7%; IMA, 100%) and vascular (BOS, 100%; IMA, not applicable) TEAEs who were readministered study drug. No pts had dose interruptions due to hypertension TEAEs. Cardiac, vascular and hypertension TEAEs resolved in 57.7%, 75.0% and 35.7% of pts receiving BOS and 65.2%, 66.7% and 48.3% receiving IMA. Conclusions: In this final analysis of BFORE, the incidence of cardiac, vascular, and hypertension TEAEs in pts with newly diagnosed CP CML receiving BOS or IMA was low and was similar between treatment groups. These AEs infrequently led to treatment discontinuation. In addition to continued improved efficacy with BOS vs IMA after 5 yrs follow-up (Brümmendorf et al., ASH 2020), these safety results support the use of first-line BOS as a standard of care in pts with CP CML. Disclosures Cortes: Bristol-Myers Squibb: Research Funding; BiolineRx: Consultancy, Research Funding; Takeda: Consultancy, Research Funding; BioPath Holdings: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Pfizer: Consultancy, Research Funding; Amphivena Therapeutics: Research Funding; Arog: Research Funding; Jazz Pharmaceuticals: Consultancy, Research Funding; Telios: Research Funding; Astellas: Research Funding; Sun Pharma: Research Funding; Merus: Research Funding; Daiichi Sankyo: Consultancy, Research Funding; Novartis: Consultancy, Research Funding; Immunogen: Research Funding. le Coutre:Incyte: Honoraria; Pfizer: Honoraria; Novartis: Honoraria. Gambacorti-Passerini:Bristol-Myers Squibb: Consultancy; Pfizer: Honoraria, Research Funding. Hjorth-Hansen:Pfizer: Honoraria, Research Funding; Austrian Orphan Pharma: Honoraria, Research Funding; Bristol-Myers Squibb: Research Funding. Garcia-Gutiérrez:Novartis: Consultancy, Other: Travel, Accommodation, Expenses, Research Funding; Bristol-Myers Squibb: Consultancy, Other: Travel, Accommodation, Expenses, Research Funding; Pfizer: Consultancy, Other: Travel, Accommodation, Expenses, Research Funding; Incyte: Consultancy, Other: Travel, Accommodation, Expenses, Research Funding. Kota:Ariad: Honoraria; Incyte: Honoraria; Xcenda: Honoraria; Novartis: Consultancy, Honoraria; Millennium Pharmaceuticals, Inc., a wholly owned subsidiary of Takeda Pharmaceutical, Company Ltd, Cambridge, MA, USA: Honoraria; Pfizer: Consultancy, Honoraria. Purcell:Pfizer: Current Employment, Current equity holder in publicly-traded company. Viqueira:Pfizer: Current Employment, Current equity holder in publicly-traded company. Leip:Pfizer: Current Employment, Current equity holder in publicly-traded company. Brümmendorf:Takeda: Consultancy; Janssen: Consultancy; Merck: Consultancy; Pfizer: Consultancy, Honoraria, Other: Travel, Accommodation, Expenses, Research Funding; Novartis: Consultancy, Other: travel, accommodation, expenses, Research Funding.

Abstract: Introduction: Bosutinib is approved for patients with Philadelphia chromosome-positive (Ph+) chronic myeloid leukemia (CML) resistant/intolerant to prior therapy and patients with newly diagnosed Ph+ chronic phase (CP) CML. The phase 4 BYOND trial (NCT02228382) further evaluated the efficacy and safety of bosutinib in patients with previously treated CML. We report the final results from BYOND. Methods: Patients with CML resistant/intolerant to previous tyrosine kinase inhibitor therapy received bosutinib 500 mg once daily. This final analysis was based on a November 23, 2020 database lock, after 3 years of follow-up. Results: Of 163 patients who received bosutinib, 156 had Ph+ CP CML; 4 patients with accelerated phase CML and 3 with Ph−/BCR-ABL1+ CML were analyzed separately. At study completion (median follow-up, 47.8 months), 48.1% of patient with Ph+ CP CML were still receiving treatment, and 68.6% completed the study. Most common primary reason for treatment discontinuation was adverse events (AEs) (26.9% [n=42/156]). Median treatment duration was 40.9 months (range, 0.2−50.1) and median dose intensity 306.4 mg/day (range, 79.7−560.6). Dose interruptions due to AEs occurred in 76.3% of patients and dose reductions in 79.5% of patients. Dose reduction (without further reduction) to 400, 300, or 200 mg/day occurred in 35 (22.4%), 46 (29.5%), and 38 (24.4%) patients, respectively. In evaluable patients with Ph+ CP CML, 81.1% (95% CI: 73.7-87.2), 71.8% (95% CI: 63.9-78.9), 59.7% (95% CI: 51.4-67.7) and 48.3% (95% CI: 40.1−56.6) attained or maintained complete cytogenetic response, major molecular response (MMR), MR 4, and MR 4.5 respectively, at any time on treatment. The majority of patients achieved a deeper molecular response relative to baseline while on bosutinib (Table 1). Among responders, the Kaplan-Meier probabilities (95% CI) of maintaining MMR and MR 4 at 36 months were 87.2% (78.0−92.7) and 80.7% (69.4−88.1), respectively. No patients with Ph+ CP CML progressed to accelerated/blast phase on-treatment. At 48 months, the cumulative incidence of progression free-survival events was 5.1% (95% CI: 2.4-9.4) and the Kaplan-Meier overall survival rate 88.3% (95% CI: 81.8-92.6). There were 17 deaths; 2 were considered CML-related (off-treatment progression to AP/BP, n=1; cardiogenic shock, n=1) and none were considered to be treatment-related by the investigator. In the overall patient population (N=163), any grade treatment-emergent AEs (TEAEs) were reported by 99.4% of patients and grade 3/4 TEAEs were reported by 79.1% of patients (Table 2). Most common (≥10%) TEAEs leading to dose reduction were diarrhea (27.0%) and increased ALT (12.3%) and most common TEAEs leading to temporary dose interruption were diarrhea (30.7%), increased ALT (14.7%), vomiting (13.5%), increased AST (11.0%), and nausea (10.4%). AEs leading to treatment discontinuation in ≥2% of patients were increased ALT (4.9%) and AST (2.5%). Conclusions: After 3 years, bosutinib continued to show efficacy in previously treated patients with Ph+ CP CML. Long-term AEs were generally manageable and consistent with previous reports of bosutinib. These results confirm the use of bosutinib as a standard of care in previously treated patients with CML. Figure 1 Figure 1. Disclosures Gambacorti-Passerini: Pfizer: Honoraria, Research Funding; Bristol-Myers Squibb: Consultancy. Brümmendorf: Bristol Myers: Research Funding; Novartis: Honoraria, Patents & Royalties, Research Funding; Janssen: Honoraria; Pfizer: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Repeat Diagnostics: Research Funding; Takepart Media: Honoraria. Abruzzese: Incyte: Consultancy, Honoraria; Novartis: Consultancy, Honoraria; Pfizer: Consultancy, Honoraria; Bristol Myers Squibb: Consultancy, Honoraria. Kelly: Takeda: Consultancy; AstraZeneca: Consultancy; Sanofi-Aventis: Consultancy; Denovo Biopharma: Consultancy; Verastem: Consultancy; Amgen: Consultancy; Berkley Lights: Current equity holder in publicly-traded company; Agios: Current equity holder in publicly-traded company; Bayer: Speakers Bureau; Janssen: Speakers Bureau; Novartis: Speakers Bureau; Celgene: Speakers Bureau; Epizyme: Speakers Bureau; Pharmacyclics: Speakers Bureau; Karyopharm: Speakers Bureau; Gilead: Speakers Bureau. Oehler: OncLive: Honoraria; Takeda: Consultancy; Pfizer: Research Funding; BMS: Consultancy. Garcia-Gutiérrez: Bristol-Myers Squibb: Consultancy; Novartis: Consultancy; Incyte: Consultancy; Pfizer: Research Funding. Hjorth-Hansen: Pfizer: Research Funding; Novartis: Research Funding; AOP: Research Funding. Leip: Pfizer: Current Employment, Current equity holder in publicly-traded company. Purcell: Pfizer: Current Employment, Current equity holder in publicly-traded company. Luscan: Pfizer: Current Employment, Current equity holder in publicly-traded company. Viqueira: Pfizer: Current Employment, Current equity holder in publicly-traded company. Giles: Novartis: Consultancy; Actutate Therapeutics: Current Employment; Epigene Therapeutics: Consultancy, Current equity holder in publicly-traded company. Hochhaus: Pfizer: Research Funding; Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding; Bristol-Myers Squibb: Research Funding; Incyte: Research Funding.