Tyrosine Kinase Inhibitor Discontinuation in Chronic Myeloid Leukemia: Strategies to Optimize Success and New Directions

PURPOSE OF REVIEW

The discovery that patients suffering from chronic myeloid leukemia who obtain deep and long-lasting molecular responses upon treatment with tyrosine kinase inhibitors may maintain their disease silent for many years after therapy discontinuation launched the era of treatment-free remission as a key management goal in clinical practice. The purpose of this review on treatment-free remission is to discuss clinical advances, highlight knowledge gaps, and describe areas of research.

RECENT FINDINGS

Patients in treatment-free remission are a minority, and it is believed that some may still retain a reservoir of leukemic stem cells; thus, whether they can be considered as truly cured is uncertain. Strengthening BCR::ABL1 inhibition increases deep molecular responses but is not sufficient to improve treatment-free remission, and we lack biomarkers to identify and specifically target residual cells with aggressive potential. Another level of complexity resides in the intra- and inter-patient clonal heterogeneity of minimal residual disease and characteristics of the bone marrow environment. Finding determinants of deep molecular responses achievement and elucidating varying biological mechanisms enabling either post-tyrosine kinase inhibitor chronic myeloid leukemia control or relapse may help develop innovative and safe therapies. In the light of the increasing prevalence of CML, targeting the residual leukemic stem cell pool is thought to be the key.

Asciminib monotherapy in patients with chronic-phase chronic myeloid leukemia with the T315I mutation after ≥1 prior tyrosine kinase inhibitor: 2-year follow-up results

Asciminib targets the BCR::ABL1 myristoyl pocket, maintaining activity against BCR::ABL1T315I, which is resistant to most approved adenosine triphosphate-competitive tyrosine kinase inhibitors. We report updated phase I results (NCT02081378) assessing safety/tolerability and antileukemic activity of asciminib monotherapy 200 mg twice daily in 48 heavily pretreated patients with T315I-mutated chronic-phase chronic myeloid leukemia (CML-CP; data cutoff: January 6, 2021). With 2 years' median exposure, 56.3% of patients continued receiving asciminib. Overall, 62.2% of evaluable patients achieved BCR::ABL1 ≤1% on the International Scale (IS); 47.6% and 81.3% of ponatinib-pretreated and -naive patients, respectively, achieved BCR::ABL1IS ≤1%. Of 45 evaluable patients, 48.9% achieved a major molecular response (MMR, BCR::ABL1IS ≤0.1%), including 34.6% and 68.4% of ponatinib-pretreated and -naive patients, respectively. MMR was maintained until data cutoff in 19 of 22 patients who achieved it. The most common grade ≥3 adverse events (AEs) included increased lipase level (18.8%) and thrombocytopenia (14.6%). Five (10.4%) patients experienced AEs leading to discontinuation, including 2 who discontinued asciminib and died due to COVID-19; these were the only deaths reported. These results show asciminib's effectiveness, including in almost 50% of ponatinib pretreated patients, and confirm its risk-benefit profile, supporting its use as a treatment option for T315I-mutated CML-CP.

BCR::ABL1 Kinase N-lobe Mutants Confer Moderate to High Degrees of Resistance to Asciminib

Secondary kinase domain mutations in BCR::ABL1 represent the most common cause of resistance to tyrosine kinase inhibitor (TKI) therapy in chronic myeloid leukemia patients. The first five approved BCR::ABL1 TKIs target the ATP-binding pocket. Mutations confer resistance to these ATP-competitive TKIs and those approved for other malignancies by decreasing TKI affinity and/or increasing ATP affinity. Asciminib, the first highly active allosteric TKI approved for any malignancy, targets an allosteric regulatory pocket in the BCR::ABL1 kinase C-lobe. As a non-ATP-competitive inhibitor, the activity of asciminib is predicted to be impervious to increases in ATP affinity. Here we report several known mutations that confer resistance to ATP-competitive TKIs in the BCR::ABL1 kinase N-lobe that are distant from the asciminib binding pocket yet unexpectedly confer in vitro resistance to asciminib. Among these is BCR::ABL1 M244V, which confers clinical resistance even to escalated asciminib doses. We demonstrate that BCR::ABL1 M244V does not impair asciminib binding, thereby invoking a novel mechanism of resistance. Molecular dynamics simulations of the M244V substitution implicate stabilization of an active kinase conformation through impact on the -C helix as a mechanism of resistance. These N-lobe mutations may compromise the clinical activity of ongoing combination studies of asciminib with ATP-competitive TKIs.

Chronic myeloid leukemia diagnosed in pregnancy: management and outcome of 87 patients reported to the European LeukemiaNet international registry

The management of chronic myeloid leukemia (CML) diagnosed during pregnancy is a rare and challenging situation. We report the treatment and outcome of 87 cases diagnosed in chronic phase from 2001-2022 derived from the largest international observational registry, supported by the European LeukemiaNet (ELN), of 400 pregnancies in 299 CML women. Normal childbirth occurred in 76% without an increased rate of birth abnormalities or life-threatening events, including in patients untreated or treated with interferon-α and/or imatinib in 2nd-3rd trimester. The low birth weight rate of 12% was comparable to that seen in the normal population. Elective and spontaneous abortions occurred in 21% and 3%, respectively. The complete hematologic response rate before labor was 95% with imatinib and 47% with interferon only. No disease progression during pregnancy was observed, 28% of the patients switched their therapy at varying times after delivery. Treatment options balance the efficacy and safety for mother and infant: interferon-α can commence in the 1st trimester and continued throughout in cases of good disease control and tolerability. Because of limited placental crossing, selected tyrosine kinase inhibitors (imatinib and nilotinib) seem to be safe and effective options in 2nd and 3rd trimester while hydroxycarbamide offers few benefits.

Dose modification dynamics of ponatinib in patients with chronic-phase chronic myeloid leukemia (CP-CML) from the PACE and OPTIC trials

Ponatinib, the only approved all known-BCR::ABL1 inhibitor, is a third-generation tyrosine-kinase inhibitor (TKI) designed to inhibit BCR::ABL1 with or without any single resistance mutation, including T315I, and induced robust and durable responses at 45 mg/day in patients with CP-CML resistant to second-generation TKIs in the PACE trial. However, cardiovascular toxicities, including arterial occlusive events (AOEs), have emerged as treatment-related AEs within this class of TKIs. The OPTIC trial evaluated the efficacy and safety of ponatinib using a novel, response-based, dose-reduction strategy in patients with CP-CML whose disease is resistant to ≥2 TKIs or who harbor T315I. To assess the dose-response relationship and the effect on the safety of ponatinib, we examined the outcomes of patients with CP-CML enrolled in PACE and OPTIC who received 45 mg/day of ponatinib. A propensity score analysis was used to evaluate AOEs across both trials. Survival rates and median time to achieve ≤1% BCR::ABL1IS in OPTIC were similar or better than in PACE. The outcomes of patients with T315I mutations were robust in both trials. Patients in OPTIC had a lower exposure-adjusted incidence of AOEs compared with those in PACE. This analysis demonstrates that response-based dosing for ponatinib improves treatment tolerance and mitigates cardiovascular risk.

[Optimizing the use of bosutinib in patients with chronic-phase chronic myeloid leukemia: Recommendations of a panel of experts from the Fi-LMC (French CML working group)]

The treatment of chronic myeloid leukemia relies on orally available tyrosine kinase inhibitors targeting the BCR::ABL1 oncoprotein. Bosutinib is a second generation adenosine triphosphate-competitive inhibitor approved for use in frontline adult chronic phase-chronic myeloid leukemia and all phases-chronic myeloid leukemia in the second line setting or beyond. Its efficacy was demonstrated in several pivotal clinical trials at 400mg once daily in the first line context and at 500mg once daily beyond first line. Bosutinib-related adverse events frequently occur early after treatment initiation and include gastro-intestinal symptoms and cytolytic hepatitis. These drug-related adverse events must be properly managed in order to preserve safety, efficacy and treatment acceptability. The French chronic myeloid leukemia study group gathered a panel of experts in hematology, pharmacology and hepatology in order to elaborate practical recommendations on the management of bosutinib treatment. These recommendations aim at optimizing the short and long-term tolerance and benefit/risk balance of bosutinib, mainly focusing at gastro-intestinal and liver toxicities.

Treatment-free remission after dasatinib in patients with chronic myeloid leukaemia in chronic phase with deep molecular response: Final 5-year analysis of DASFREE

Patients with chronic myeloid leukaemia in chronic phase (CML-CP) who have a sustained deep molecular response (DMR) are eligible to discontinue treatment and attempt treatment-free remission (TFR). In the DASFREE study (ClinicalTrials.gov; NCT01850004), the 2-year TFR rate after dasatinib discontinuation was 46%; here we present the 5-year update. Patients with a stable DMR after ≥2 years of dasatinib therapy discontinued treatment and were followed for 5 years. At a minimum follow-up of 60 months, in 84 patients discontinuing dasatinib, the 5-year TFR rate was 44% (n = 37). No relapses occurred after month 39 and all evaluable patients who relapsed and restarted dasatinib (n = 46) regained a major molecular response in a median of 1.9 months. The most common adverse event during the off-treatment period was arthralgia (18%, 15/84); a total of 15 withdrawal events were reported in nine patients (11%). At the 5-year final follow-up, almost half of the patients who discontinued dasatinib after a sustained DMR maintained TFR. All evaluable patients who experienced a relapse quickly regained a DMR after restarting dasatinib, demonstrating that dasatinib discontinuation is a viable and potentially long-term option in patients with CML-CP. The safety profile is consistent with the previous report.

Health care resource utilization in 3L + patients with chronic phase chronic myeloid leukemia receiving asciminib or bosutinib

OBJECTIVES

To assess and compare health care resource utilization (HCRU) rates of asciminib and bosutinib at the Week 24, Week 48, and Week 96 cutoffs among 3L + patients with chronic myeloid leukemia in chronic phase (CML-CP) in the randomized ASCEMBL trial.

METHODS

Patients in the ASCEMBL trial (Clinicaltrials.gov: NCT03106779) were randomized to receive asciminib 40 mg twice daily (n = 157) or bosutinib 500 mg once daily (n = 76). At each scheduled visit, investigators conducted HCRU assessment on hospitalization, emergency room visit, general practitioner visit, specialist visit and urgent care visit; duration and type of hospitalization for the hospitalized patients; and reasons for HCRU. The number of patients with HCRU, rate of HCRU per patient-year, and length of hospital stay by ward type were compared at Week 24, Week 48 and Week 96 analyses.

RESULTS

Lower proportions of patients receiving asciminib versus bosutinib used any resources including hospitalizations, emergency room visits, general practitioner visits, specialist visits, and urgent care visits (23.6% versus 36.8%, 26.1% versus 39.5%, and 28.6% versus 42.6% at Week 24, Week 48, and Week 96 analyses respectively). After normalizing for treatment exposure, rates of HCRU for any resource per patient-year were significantly lower for asciminib versus bosutinib: 0.25 (95% CI: 0.18-0.34) versus 0.80 (95% CI: 0.55-1.16) at the Week 24 analysis, 0.20 (95% CI: 0.15-0.27) versus 0.47 (95% CI: 0.32-0.66) at the Week 48 analysis, and 0.17 (95% CI: 0.12-0.22) versus 0.40 (95% CI: 0.27-0.55) at the Week 96 analysis. Among the hospitalized patients, mean length of hospital stay was lower for asciminib than bosutinib for most wards at all three timepoints.

CONCLUSIONS

In the ASCEMBL trial, asciminib-treated patients with CML-CP in 3L + maintained lower resource utilization compared to bosutinib over the long-term.

Using Measurable Residual Disease to Optimize Management of AML, ALL, and Chronic Myeloid Leukemia

In this review, we discuss the use of measurable residual disease (MRD) in AML, ALL, and chronic myeloid leukemia (CML). Our aims were to review the different methodologies for MRD assessment; describe the clinical relevance and medical decision making on the basis of MRD; compare and contrast the usage of MRD across AML, ALL, and CML; and discuss what patients need to know about MRD as it relates to their disease status and treatment. Finally, we discuss ongoing challenges and future directions with the goal of optimizing MRD usage in leukemia management.

First-line second generation tyrosine kinase inhibitors in patients with newly diagnosed accelerated phase chronic myeloid leukemia

Accelerated phase (AP) CML at onset and have poorer prognosis than CP-CML. We hypothesize that off-license use of second generation TKI (TKI2) as front-line therapy might counterbalance this poor prognosis, with limited toxicity. In "real-life" conditions, newly diagnosed patients meeting the ELN cytological criteria for AP-CML or harboring ACA and treated with first-line TKI2 were included in this retrospective multicenter observational study. We enrolled 69 patients [69.5 % male, median age 49.5 years, median follow-up 43.5 months], segregated into hematologic AP [HEM-AP (n = 32)] and cytogenetically defined AP [ACA-AP (n = 37)]. Hematologic parameters were worse in HEM-AP [spleen size (p = 0.014), PB basophils (p < .001), PB blasts (p < .001), PB blasts+promyelocytes (p < .001), low hemoglobin levels (p < .001)]. Dasatinib was initiated in 56 % patients in HEM-AP and in 27 % in ACA-AP, nilotinib in 44 % and 73 % respectively. Response and survival do not differ, regardless of the TKI2: 81 % vs 84.3 % patients achieved CHR, 88 % vs 84 % CCyR, 73 % vs 75 % MMR respectively. The estimated 5-year PFS 91.5 % (95%CI: 84.51-99.06 %) and 5-year OS 96.84 % (95%CI: 92.61-100 %). Only BM blasts (p < 0.001) and BM blasts+promyelocytes (p < 0.001) at diagnosis negatively influenced OS. TKI2 as front-line therapy in newly diagnosed AP-CML induce excellent responses and survival, and counterbalance the negative impact of advanced disease phase.

Asciminib monotherapy in patients with CML-CP without BCR::ABL1 T315I mutations treated with at least two prior TKIs: 4-year phase 1 safety and efficacy results

Asciminib is approved for patients with Philadelphia chromosome-positive chronic-phase chronic myeloid leukemia (CML-CP) who received ≥2 prior tyrosine kinase inhibitors or have the T315I mutation. We report updated results of a phase 1, open-label, nonrandomized trial (NCT02081378) assessing the safety, tolerability, and antileukemic activity of asciminib monotherapy 10-200 mg once or twice daily in 115 patients with CML-CP without T315I (data cutoff: January 6, 2021). After ≈4-year median exposure, 69.6% of patients remained on asciminib. The most common grade ≥3 adverse events (AEs) included increased pancreatic enzymes (22.6%), thrombocytopenia (13.9%), hypertension (13.0%), and neutropenia (12.2%); all-grade AEs (mostly grade 1/2) included musculoskeletal pain (59.1%), upper respiratory tract infection (41.7%), and fatigue (40.9%). Clinical pancreatitis and arterial occlusive events (AOEs) occurred in 7.0% and 8.7%, respectively. Most AEs occurred during year 1; the subsequent likelihood of new events, including AOEs, was low. By data cutoff, among patients without the indicated response at baseline, 61.3% achieved BCR::ABL1 ≤ 1%, 61.6% achieved ≤0.1% (major molecular response [MMR]), and 33.7% achieved ≤0.01% on the International Scale. MMR was maintained in 48/53 patients who achieved it and 19/20 who were in MMR at screening, supporting the long-term safety and efficacy of asciminib in this population.

Efficacy and safety of nilotinib in chronic myeloid leukaemia patients who failed to achieve a treatment-free remission period after imatinib discontinuation: Results of the French Nilo post-STIM study

Molecular recurrence (MRec) occurs in about half of all patients with chronic myeloid leukaemia (CML) who discontinue tyrosine kinase inhibitors (TKI) in sustained deep molecular response. A second TKI discontinuation has been attempted in some patients who regain the discontinuation criteria after resuming treatment. Nilotinib treatment affords faster and deeper molecular responses than imatinib as first-line therapy. We prospectively evaluated the efficacy and safety of nilotinib (300 mg twice daily) in chronic-phase CML patients who experienced MRec, after imatinib discontinuation and analysed the probability of TFR after a new attempt in patients treated for 2 years with sustained MR^4.5 for at least 1 year. A total of 31 patients were included in the study between 2013 and 2018. Seven (23%) patients experienced serious adverse events after a median of 2 months of nilotinib treatment leading to discontinuation of treatment. One patient was excluded from the study for convenience. Among the 23 patients treated for 2 years with nilotinib, 22 maintained their molecular response for at least 1 year (median: 22 months) and stopped nilotinib. The TFR rates at 24 and 48 months after nilotinib discontinuation were 59.1% (95% confidence interval [CI]: 41.7%-83.7%) and 42.1% (95% CI: 25%-71%) respectively (NCT #01774630).

Dasatinib plus Peg-Interferon alpha 2b combination in newly diagnosed chronic phase chronic myeloid leukaemia: Results of a multicenter phase 2 study (DASA-PegIFN study)

Superior rates of deep molecular response (DMR) have been reported with the combination of tyrosine kinase inhibitors and pegylated-interferon-alpha (Peg-IFN) in patients with newly diagnosed chronic phase-chronic myeloid leukaemia (CP-CML). In this setting, this study investigated the efficacy and safety of dasatinib combined to Peg-IFN-α2b (Dasa-PegIFN, NCT01872442). A total of 79 patients (age ≤65 years) started dasatinib; 61 were eligible for Peg-IFNα-2b add-on therapy at month 3 for a maximum 21-months duration. Dasatinib was continued thereafter. The primary endpoint was the cumulative rate of molecular response 4.5 log (MR^4.5 ) by 12 months. The results are reported for the 5-year duration of the study. Grade 3 neutropenia was frequent with the combination but did not induce severe infection (one of grade 3). Other adverse events were generally low grade (4% of grade 3-4) and expected. Seventy-nine per cent and 61% of patients continued the Peg-IFN until months 12 and 24, respectively. Overall, at these time points, MR^4.5 rates were 25% and 38%, respectively. Thereafter, 32% and 46% of patients achieved a sustained (≥2 years) MR^4.5 or MR⁴ , respectively. This work established the feasibility and high rates of achievement of early and sustained DMR (a prerequisite for treatment-free-remission) with dasatinib and Peg-IFNα-2b combination as initial therapy.

Ponatinib after failure of second-generation tyrosine kinase inhibitor in resistant chronic-phase chronic myeloid leukemia

Ponatinib, the only third-generation pan-BCR::ABL1 inhibitor with activity against all known BCR::ABL1 mutations including T315I, has demonstrated deep and durable responses in patients with chronic-phase chronic myeloid leukemia (CP-CML) resistant to prior second-generation (2G) TKI treatment. We present efficacy and safety outcomes from the Ponatinib Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ ALL) and CML Evaluation (PACE) and Optimizing Ponatinib Treatment in CP-CML (OPTIC) trials for this patient population. PACE (NCT01207440) evaluated ponatinib 45 mg/day in CML patients with resistance to prior TKI or T315I. In OPTIC (NCT02467270), patients with CP-CML and resistance to ≥2 prior TKIs or T315I receiving 45 or 30 mg/day reduced their doses to 15 mg/day upon achieving ≤1% BCR::ABL1^IS or received 15 mg/day continuously. Efficacy and safety outcomes from patients with CP-CML treated with ≥1 2G TKI (PACE, n = 257) and OPTIC (n = 93), 45-mg starting dose cohort, were analyzed for BCR::ABL1^IS response rates, overall survival (OS), progression-free survival (PFS), and safety. By 24 months, the percentages of patients with ≤1% BCR::ABL1^IS response, PFS, and OS were 46%, 68%, and 85%, respectively, in PACE and 57%, 80%, and 91%, respectively, in OPTIC. Serious treatment-emergent adverse events and serious treatment-emergent arterial occlusive event rates were 63% and 18% in PACE and 34% and 4% in OPTIC. Ponatinib shows high response rates and robust survival outcomes in patients whose disease failed prior to 2G TKIs, including patients with T315I mutation. The response-based dosing in OPTIC led to improved safety and similar efficacy outcomes compared with PACE.

Efficacy and safety results from ASCEMBL, a phase 3 study of asciminib versus bosutinib (BOS) in patients (pts) with chronic myeloid leukemia in chronic phase (CML-CP) after ≥2 prior tyrosine kinase inhibitors (TKIs): Week 96 update

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Background: Asciminib is the first BCR::ABL1 inhibitor to specifically target the ABL Myristoyl Pocket (STAMP). In the ASCEMBL primary analysis, asciminib had superior efficacy and better safety/tolerability than BOS in pts with CML-CP after ≥2 prior TKIs. After a median follow-up of 2.3 years (16.5 months’ additional follow-up since primary analysis), we report efficacy and safety results (cutoff: October 6, 2021). Methods: Eligible pts were adults with CML-CP after ≥2 prior TKIs, with intolerance or lack of efficacy per 2013 European LeukemiaNet. Pts were randomized 2:1 to asciminib 40 mg twice daily or BOS 500 mg once daily, stratified by major cytogenetic response (MCyR) status (Ph+ metaphases ≤35%) at baseline. The key secondary endpoint was major molecular response (MMR) rate at wk 96. Results: 233 pts were randomized to asciminib (n=157) or BOS (n=76). At cutoff, treatment was ongoing in 84 (53.5%) and 15 (19.7%) pts, respectively; the most common reason for discontinuation was lack of efficacy in 38 (24.2%) and 27 (35.5%) pts, respectively. MMR rate at wk 96 (per ITT) was higher on asciminib (37.6%) than BOS (15.8%). The difference, adjusting for baseline MCyR, was 21.7% (95% CI, 10.5%-33.0%; 2-sided P=.001). More pts on asciminib than BOS, respectively, had BCR::ABL1IS ≤1% (45.1% vs 19.4%) at wk 96. The probability of maintaining MMR and BCR::ABL1IS ≤1% for ≥72 wk was 96.7% (95% CI, 87.4%-99.2%) and 94.6% (95% CI, 86.2%-97.9%), respectively, on asciminib and 92.9% (95% CI, 59.1%-99.0%) and 95.0% (95% CI, 69.5%-99.3%), respectively, on BOS. Median duration of exposure was 103.1 (range, 0.1-201.1) wk on asciminib and 30.5 (range, 1.0-188.3) wk on BOS. Despite the longer duration of asciminib exposure, safety/tolerability of asciminib continued to be better than that of BOS (Table). No new on-treatment deaths were reported since the primary analysis. Most frequent (>10%) grade ≥3 adverse events (AEs) on asciminib vs BOS were thrombocytopenia (22.4%, 9.2%), neutropenia (18.6%, 14.5%), diarrhea (0%, 10.5%), and increased alanine aminotransferase (0.6%, 14.5%). Conclusions: After >2 years of follow-up, asciminib continued to show superior efficacy and better safety/tolerability vs BOS. Responses were durable, with more pts on asciminib in MMR. Additionally, more pts on asciminib had BCR::ABL1IS ≤1%, a milestone response in later lines associated with improved survival. These results continue to support the use of asciminib as a new CML therapy, with the potential to transform standard of care. Clinical trial information: NCT03106779. [Table: see text]

Kinetics of early and late molecular recurrences after first-line imatinib cessation in chronic myeloid leukemia: updated results from the STIM2 trial

Discontinuation of tyrosine kinase inhibitors in chronic phase chronic myeloid leukemia is feasible in clinical practice based on recently published international recommendations. Nevertheless, factors predictive of molecular recurrence have not been fully elucidated and long-term follow-up of patients enrolled in clinical studies are required in order to update knowledge on discontinuation attempts particularly in terms of the safety and durability of treatment-free remission (TFR). In the current study, we updated results from the STIM2 study in the light of the consensual criterion of molecular recurrence reported in different international recommendations. Among the 199 patients included in the perprotocol study, 108 patients lost a major molecular response. With a median follow-up of 40.8 months (5.5-111 months), the probability of treatment-free remission was 43.4% [36.3-50.4] at 5 years, 40.9% [32.8-47.3] at 7 years and 34.5% [25.6- 43.3] at 9 years. Molecular recurrence occurred between 0 to 6 months, 6 to 24 months and after 24 months in 75 patients (69%), 15 patients (14%) and 18 patients (17%), respectively. Notably, the kinetics of molecular recurrence differed significantly between these three subgroups with a median time from loss of MR4 (BCR::ABL1 IS≤0.01%) to loss of major molecular response of 1, 7 and 22 months, respectively. Predictive factors of molecular recurrence differed according to the time of occurrence of the molecular recurrence. Durations of imatinib treatment and deep molecular response as well as BCR::ABL1/ABL1 levels at cessation of tyrosine kinase inhibitor treatment, as quantified by reverse transcriptase droplet digital polymerase chain reaction, are involved in molecular recurrence occurring up to 24 months but not beyond. (ClinicalTrial. gov Identifier NCT#0134373).

Managing hematological cancer patients during the COVID-19 pandemic: an ESMO-EHA Interdisciplinary Expert Consensus

BACKGROUND

The COVID-19 pandemic has created enormous challenges for the clinical management of patients with hematological malignancies (HMs), raising questions about the optimal care of this patient group.

METHODS

This consensus manuscript aims at discussing clinical evidence and providing expert advice on statements related to the management of HMs in the COVID-19 pandemic. For this purpose, an international consortium was established including a steering committee, which prepared six working packages addressing significant clinical questions from the COVID-19 diagnosis, treatment, and mitigation strategies to specific HMs management in the pandemic. During a virtual consensus meeting, including global experts and lead by the European Society for Medical Oncology and the European Hematology Association, statements were discussed and voted upon. When a consensus could not be reached, the panel revised statements to develop consensual clinical guidance.

RESULTS AND CONCLUSION

The expert panel agreed on 33 statements, reflecting a consensus, which will guide clinical decision making for patients with hematological neoplasms during the COVID-19 pandemic.

Sacubitril-valsartan improves radial and longitudinal strain and ejection fraction in C57Bl/6 mice treated with doxorubicin through NLRP3 mediated pathways and reduction of cytokine storm

Funding Acknowledgements

Type of funding sources: Public grant(s) – EU funding. Main funding source(s): Ricerca Corrente grant, Ministero della Salute (it)

Background

Doxorubicin-mediated adverse cardiovascular events are among the leading causes of morbidity and mortality in breast cancer patients. Sacubitril-valsartan (LCZ 696) is a combination drug, made up of neprilysin inhibitor sacubitril and angiotensin II receptor blocker valsartan, used for the treatment of heart failure in patients with a reduced ejection fraction.

Hypothesis

we hypothesized that LCZ 696, administered during doxorubicin, could improve cardiac functions in preclinical models

Methods

 C57Bl/6 mice were untreated (Sham, n = 6) or treated for 10 days with doxorubicin i.p at 2.17 mg/kg (DOXO, n = 6), LCZ-696 at 60 mg/kg (LCZ, n = 6) or doxorubicin combined to LCZ-696 (DOXO-LCZ, n = 6). Before and after treatments, ejection fraction (EF) and radial and longitudinal strain were analyzed through transthoracic echocardiography (Vevo 2100). After treatment, mice were sacrificed and cardiac tissues were treated for determination of NLRP3 inflammasome, Myd88, NF-kB and cytokines involved in heart failure and arrhythmias (IL-1α, IL-1β, IL-2, IL-4, IL-6, IL-10, IL-12, IL17-α, IL-18, IFN-γ, TNF-α, G-CSF, and GM-CSF).

Results

LCZ 696 improved significantly the EF and prevented the reduction of radial and longitudinal strain after 10 days of treatment with doxorubicin. No significant differences were observed for IVS;d-D, LVID;d-D, LVPW;d-D, LV Mass, LV Vol; d, LV Vol;s between the experimental groups.  A reduced expression of NLRP3, MyD88 and NF-kB in cardiac tissues was seen in DOXO-LCZ group compared to DOXO mice (p &lt; 0.001). Cardiac expression of IL-1β, IL-6, TNF-α, G-CSF and GM-CSF were significantly reduced (p &lt; 0.001) after treatment with LCZ-696 indicating anti-inflammatory and cardioprotective properties.

Conclusion

LCZ-696 improves cardiac functions in mice treated with doxorubicin. Biochemically, these effects are mediated by the downregulation of NLRP3 inflammasome-related pathways and cytokines involved in doxorubicin-mediated heart failure and cardiomyopathies.

Ipilimumab and Nivolumab exertes cardiotoxic and pro-fibrotic effects in mice through the overexpression of NLRP3 inflammasome, chemokines and leukotrienes

Background

Several strategies based on immune checkpoint inhibitors (ICIs) have been developed for cancer therapy, opening to advantages in cancer outcomes. However, several ICIs-induced side effects emerged in these patients, especially a rare but clinically significant cardiotoxicity with high rate of mortality.

Purpose

We studied cytotoxic and pro-inflammatory properties of Ipilimumab and Nivolumab in cellular and preclinical models

Methods

Co-cultures of human cardiomyocytes and hPBMCs were exposed to Ipilimumab or Nivolumab at 100 nM; cell viability and expression of leukotrienes, NLRP3 inflammasome, MyD88 (myddosome) and p65/NF-kB were performed. C57 mice were untreated (Sham; n=6) or treated with Ipilimumab (IPI, n=6) (15 mg/kg); analysis of fractional shortening, ejection fraction, radial and longitudinal strain were made before and after treatments through 2D-echocardiography (Vevo 2100). Expression of NLRP3, MyD88, p65/NF-kB, leukotrienes and 12 cytokines (IL-1α, IL-1β, IL-2, IL-4, IL-6, IL-10, IL-12, IL17-α, IFN-γ, TNF-α, G-CSF, and GM-CSF) have been analyzed in murine myocardium.

Results

Nivolumab and Ipilimumab induced cell death and apoptosis in cardiomyocutes. Both ICIs increased NLRP3, MyD88 and p65/NF-kB expression compared to untreated cells, however the most pro-inflammatory and cardiotoxic effects were seen after exposure to Ipilimumab. Mice treated with Ipilimumab showed a significant decrease of fractional shortening and radial strain compared to untreated mice. Metabolic studies clearly indicates that ipilimumab increases leukotrienes production and NLRP3 expression in heart tissues, probably due to increased iROS content (iROS are key inductors of leukotrienes expression). High expression of IL-6, IL-1 and IL-17 were also seein in mice treated with ipilimumab (p&lt;0,001).

Conclusions

Nivolumab and Ipilimumab exert cytotoxic effects mediated by NLRP3 inflammasome, leukotrienes and pro-inflammatory cytokines in heart tissues.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Ministero della Salute, Ricerca Corrente Project

The combination of a neprilysin inhibitor (sacubitril) and angiotensin-II receptor blocker (valsartan) improves ejection fraction and longitudinal strain in mice treated with doxorubicin through NLRP3

Background

Doxorubicin-mediated- adverse cardiovascular events are among the leading causes of morbidity and mortality in breast cancer patients. Sacubitril-valsartan (LCZ 696) is a combination drug, made up of neprilysin inhibitor sacubitril and angiotensin II receptor blocker valsartan, used for the treatment of heart failure in patients with a reduced ejection fraction.

Purpose

Here, we aim to assess whether LCZ 696, administered during doxorubicin, reduces in vitro anticancer drugs-related cardiotoxicity compared to Valsartan (V), used as a control drug.

Methods

Human fetal cardiomyocytes (HFC cell line) were exposed to subclinical concentration of doxorubicin (at 200 nM) alone or in combination with LCZ-696 (100 mM) for 72 h. After the incubation period, we performed the following tests: determination of cell viability, through analysis of mitochondrial dehydrogenase activity, study of lipid peroxidation (quantifying cellular Malondialdehyde and 4-hydroxynonenal), intracellular Ca2+ homeostasis. Moreover, pro-inflammatory studied were also performed (activation of NLRP3 inflammasome; expression of TLR4/MyD88; mTORC1 Fox01/3a; transcriptional activation of p65/NF-κB and secretion of cytokines involved in cardiotoxicity (Interleukins 1β, 8, 6). C57Bl/6 mice were untreated (Sham, n=6) or treated for 10 days with doxorubicin (DOXO, n=6), LCZ-696 (LCZ, n=6) or doxorubicin combined to LCZ-696 (DOXO-LCZ, n=6). DOXO was injected intraperitoneally. Ejection fraction, radial and longitudinal strain were analyzed through transthoracic echocardiography (Vevo 2100). Cardiac tissue expression of NLRP3 inflammasome, Myd8, NF-kB and chemokines and cytokines were quantified after treatments through ELISA method.

Results

LCZ 696 co-incubated with doxorubicin exerts cardioprotective effects, enhancing cell viability of 48–54.6% compared to only doxorubicin-treated cells (p&lt;0,001 for all); LCZ 696 reduced significantly the cardiotoxicity through MyD88/NF-KB/cytokines axis and mTORC1 Fox01/3α mediated mechanisms. In preclinical study, LCZ 696 improved significantly the EF and prevented the reduction of radial and longitudinal strain after 10 days of treatment with doxorubicin. A reduced expression of pro-inflammatory cytokines, NLRP3, MyD88 and NF-kB in heart tissues was also seen in DOXO-LCZ group compared to DOXO mice (p&lt;0.001)

Conclusion

We demonstrated, for the first time, that the LCZ696 exerts direct effects in cardiomyocytes and preclinical models during doxorubicin exposure, turning on a new light on its possible use in cancer patients to reduce cardiovascular side effects.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Ministero della Salute, Ricerca Corrente project

Long-term outcome of imatinib 400 mg compared to imatinib 600 mg or imatinib 400 mg daily in combination with cytarabine or pegylated interferon alpha 2a for chronic myeloid leukaemia: results from the French SPIRIT phase III randomised trial

The STI571 prospective randomised trial (SPIRIT) French trial is a four-arm study comparing imatinib (IM) 400 mg versus IM 600 mg, IM 400 mg + cytarabine (AraC), and IM 400 mg + pegylated interferon alpha2a (PegIFN-α2a) for the front-line treatment of chronic-phase chronic myeloid leukaemia (CML). Long-term analyses included overall and progression-free survival, molecular responses to treatment, and severe adverse events. Starting in 2003, the trial included 787 evaluable patients. The median overall follow-up of the patients was 13.5 years (range 3 months to 16.7 years). Based on intention-to-treat analyses, at 15 years, overall and progression-free survival were similar across arms: 85%, 83%, 80%, and 82% and 84%, 87%, 79%, and 79% for the IM 400 mg (N = 223), IM 600 mg (N = 171), IM 400 mg + AraC (N = 172), and IM 400 mg + PegIFN-α2a (N = 221) arms, respectively. The rate of major molecular response at 12 months and deep molecular response (MR4) over time were significantly higher with the combination IM 400 mg + PegIFN-α2a than with IM 400 mg: p = 0.0001 and p = 0.0035, respectively. Progression to advanced phases and secondary malignancies were the most frequent causes of death. Toxicity was the main reason for stopping AraC or PegIFN-α2a treatment.

Folic acid supplementation in postmenopausal women with hot flushes: phase III randomised double-blind placebo-controlled trial

OBJECTIVE

To assess whether folic acid supplementation ameliorates hot flushes.

DESIGN

Double-blind, placebo-controlled randomised trial.

SETTING

Nine hospitals in England.

POPULATION

Postmenopausal women experiencing ≥50 hot flushes weekly.

METHODS

Women (n = 164) were randomly assigned in a 1:1 ratio to receive folic acid 5 mg tablet or placebo daily for 12 weeks. Participants recorded frequency and severity of hot flushes in a Sloan Diary daily and completed Greene Climacteric and Utian Quality of Life (UQoL) Scales at 4-week intervals.

MAIN OUTCOME MEASURES

The change in daily Hot Flush Score at week 12 from randomisation based on Sloan Diary Composite Score B calculation.

RESULTS

Data of 143 (87%) women were available for the primary outcome. The mean change (SD) in Hot Flush Score at week 12 was -6.98 (10.30) and -4.57 (9.46) for folic acid and placebo group, respectively. The difference between groups in the mean change was -2.41 (95% CI -5.68 to 0.87) (P = 0.149) and in the adjusted mean change -2.61 (95% CI -5.72 to 0.49) (P = 0.098). Analysis of secondary outcomes indicated an increased benefit in the folic acid group regarding changes in total and emotional UQoL scores at week 8 when compared with placebo. The difference in the mean change from baseline was 5.22 (95% CI 1.16-9.28) and 1.88 (95% CI 0.23-3.52) for total and emotional score, respectively.

CONCLUSIONS

The study was not able to demonstrate that folic acid had a statistically significant greater benefit in reducing Hot Flush Score over 12 weeks in postmenopausal women when compared with placebo.

TWEETABLE ABSTRACT

Folic acid may ameliorate hot flushes in postmenopausal women but confirmation is required from a larger study.

Handling challenging questions in the management of chronic myeloid leukemia: when is it safe to stop tyrosine kinase inhibitors?

The paradigm for managing patients with chronic myeloid leukemia is evolving. In the recent past, restoring a normal life expectancy while patients are receiving never-ending targeted therapy with BCR-ABL1 tyrosine kinase inhibitors through prevention of progression to blast phase and mitigation of iatrogenic risks was considered the best achievable outcome. Now, long-term treatment-free remission with continued response off tyrosine kinase inhibitor therapy is recognized as the most optimal benefit of treatment. Indeed, numerous independent clinical trials provided solid proof that tyrosine kinase inhibitor discontinuation was feasible in patients with deep and sustained molecular responses. This article discusses when tyrosine kinase inhibitors may be safely stopped in clinical practice on the basis of the best and latest available evidence.

ETNK1 mutations induce a mutator phenotype that can be reverted with phosphoethanolamine

Recurrent somatic mutations in ETNK1 (Ethanolamine-Kinase-1) were identified in several myeloid malignancies and are responsible for a reduced enzymatic activity. Here, we demonstrate in primary leukemic cells and in cell lines that mutated ETNK1 causes a significant increase in mitochondrial activity, ROS production, and Histone H2AX phosphorylation, ultimately driving the increased accumulation of new mutations. We also show that phosphoethanolamine, the metabolic product of ETNK1, negatively controls mitochondrial activity through a direct competition with succinate at mitochondrial complex II. Hence, reduced intracellular phosphoethanolamine causes mitochondria hyperactivation, ROS production, and DNA damage. Treatment with phosphoethanolamine is able to counteract complex II hyperactivation and to restore a normal phenotype.

Integrated Genomic, Functional, and Prognostic Characterization of Atypical Chronic Myeloid Leukemia

Supplemental Digital Content is available for this article.

Atypical chronic myeloid leukemia (aCML) is a BCR-ABL1-negative clonal disorder, which belongs to the myelodysplastic/myeloproliferative group. This disease is characterized by recurrent somatic mutations in SETBP1, ASXL1 and ETNK1 genes, as well as high genetic heterogeneity, thus posing a great therapeutic challenge. To provide a comprehensive genomic characterization of aCML we applied a high-throughput sequencing strategy to 43 aCML samples, including both whole-exome and RNA-sequencing data. Our dataset identifies ASXL1, SETBP1, and ETNK1 as the most frequently mutated genes with a total of 43.2%, 29.7 and 16.2%, respectively. We characterized the clonal architecture of 7 aCML patients by means of colony assays and targeted resequencing. The results indicate that ETNK1 variants occur early in the clonal evolution history of aCML, while SETBP1 mutations often represent a late event. The presence of actionable mutations conferred both ex vivo and in vivo sensitivity to specific inhibitors with evidence of strong in vitro synergism in case of multiple targeting. In one patient, a clinical response was obtained. Stratification based on RNA-sequencing identified two different populations in terms of overall survival, and differential gene expression analysis identified 38 significantly overexpressed genes in the worse outcome group. Three genes correctly classified patients for overall survival.

Strategies to Improve Recruitment to a De-escalation Trial: A Mixed-Methods Study of the OPTIMA Prelim Trial in Early Breast Cancer

AIMS

De-escalation trials are challenging and sometimes may fail due to poor recruitment. The OPTIMA Prelim randomised controlled trial (ISRCTN42400492) randomised patients with early stage breast cancer to chemotherapy versus 'test-directed' chemotherapy, with a possible outcome of no chemotherapy, which could confer less treatment relative to routine practice. Despite encountering challenges, OPTIMA Prelim reached its recruitment target ahead of schedule. This study reports the root causes of recruitment challenges and the strategies used to successfully overcome them.

MATERIALS AND METHODS

A mixed-methods recruitment intervention (QuinteT Recruitment Intervention) was used to investigate the recruitment difficulties and feedback findings to inform interventions and optimise ongoing recruitment. Quantitative site-level recruitment data, audio-recorded recruitment appointments (n = 46), qualitative interviews (n = 22) with trialists/recruiting staff (oncologists/nurses) and patient-facing documentation were analysed using descriptive, thematic and conversation analyses. Findings were triangulated to inform a 'plan of action' to optimise recruitment.

RESULTS

Despite best intentions, oncologists' routine practices complicated recruitment. Discomfort about deviating from the usual practice of recommending chemotherapy according to tumour clinicopathological features meant that not all eligible patients were approached. Audio-recorded recruitment appointments revealed how routine practices undermined recruitment. A tendency to justify chemotherapy provision before presenting the randomised controlled trial and subtly indicating that chemotherapy would be more/less beneficial undermined equipoise and made it difficult for patients to engage with OPTIMA Prelim. To tackle these challenges, individual and group recruiter feedback focussed on communication issues and vignettes of eligible patients were discussed to address discomforts around approaching patients. 'Tips' documents concerning structuring discussions and conveying equipoise were disseminated across sites, together with revisions to the Patient Information Sheet.

CONCLUSIONS

This is the first study illuminating the tension between oncologists' routine practices and recruitment to de-escalation trials. Although time and resources are required, these challenges can be addressed through specific feedback and training as the trial is underway.

European LeukemiaNet 2020 recommendations for treating chronic myeloid leukemia

The therapeutic landscape of chronic myeloid leukemia (CML) has profoundly changed over the past 7 years. Most patients with chronic phase (CP) now have a normal life expectancy. Another goal is achieving a stable deep molecular response (DMR) and discontinuing medication for treatment-free remission (TFR). The European LeukemiaNet convened an expert panel to critically evaluate and update the evidence to achieve these goals since its previous recommendations. First-line treatment is a tyrosine kinase inhibitor (TKI; imatinib brand or generic, dasatinib, nilotinib, and bosutinib are available first-line). Generic imatinib is the cost-effective initial treatment in CP. Various contraindications and side-effects of all TKIs should be considered. Patient risk status at diagnosis should be assessed with the new EUTOS long-term survival (ELTS)-score. Monitoring of response should be done by quantitative polymerase chain reaction whenever possible. A change of treatment is recommended when intolerance cannot be ameliorated or when molecular milestones are not reached. Greater than 10% BCR-ABL1 at 3 months indicates treatment failure when confirmed. Allogeneic transplantation continues to be a therapeutic option particularly for advanced phase CML. TKI treatment should be withheld during pregnancy. Treatment discontinuation may be considered in patients with durable DMR with the goal of achieving TFR.

Asciminib in Chronic Myeloid Leukemia after ABL Kinase Inhibitor Failure

BACKGROUND

Asciminib is an allosteric inhibitor that binds a myristoyl site of the BCR-ABL1 protein, locking BCR-ABL1 into an inactive conformation through a mechanism distinct from those for all other ABL kinase inhibitors. Asciminib targets both native and mutated BCR-ABL1, including the gatekeeper T315I mutant. The safety and antileukemic activity of asciminib in patients with Philadelphia chromosome-positive leukemia are unknown.

METHODS

In this phase 1, dose-escalation study, we enrolled 141 patients with chronic-phase and 9 with accelerated-phase chronic myeloid leukemia (CML) who had resistance to or unacceptable side effects from at least two previous ATP-competitive tyrosine kinase inhibitors (TKIs). The primary objective was to determine the maximum tolerated dose or the recommended dose (or both) of asciminib. Asciminib was administered once or twice daily (at doses of 10 to 200 mg). The median follow-up was 14 months.

RESULTS

Patients were heavily pretreated; 70% (105 of 150 patients) had received at least three TKIs. The maximum tolerated dose of asciminib was not reached. Among patients with chronic-phase CML, 34 (92%) with a hematologic relapse had a complete hematologic response; 31 (54%) without a complete cytogenetic response at baseline had a complete cytogenetic response. A major molecular response was achieved or maintained by 12 months in 48% of patients who could be evaluated, including 8 of 14 (57%) deemed to have resistance to or unacceptable side effects from ponatinib. A major molecular response was achieved or maintained by 12 months in 5 patients (28%) with a T315I mutation at baseline. Clinical responses were durable; a major molecular response was maintained in 40 of 44 patients. Dose-limiting toxic effects included asymptomatic elevations in the lipase level and clinical pancreatitis. Common adverse events included fatigue, headache, arthralgia, hypertension, and thrombocytopenia.

CONCLUSIONS

Asciminib was active in heavily pretreated patients with CML who had resistance to or unacceptable side effects from TKIs, including patients in whom ponatinib had failed and those with a T315I mutation. (Funded by Novartis Pharmaceuticals; ClinicalTrials.gov number, NCT02081378.).

Towards a Personalized Treatment of Patients with Chronic Myeloid Leukemia

PURPOSE OF REVIEW

Treatment goals and ambitions have even been upwardly revised since demonstration was made that under certain conditions, treatment-free remission was possible. Herein, we will discuss on how to try tailoring treatment choices to the unique characteristics of each patient.

RECENT FINDINGS

Since the first-generation ATP-competitive TKI imatinib was made available in the clinic in 2001, second-generation drugs such as dasatinib, nilotinib and bosutinib and the third-generation TKI ponatinib have broadened the therapeutic armamentarium, providing effective salvage against intolerance and different types of resistance, or as frontline options. Management and outcomes of patients with chronic myeloid leukemia have been revolutionized by the discovery, development, and approval of BCR-ABL tyrosine kinase inhibitors (TKIs). Most patients can now expect a near-to normal life expectancy and acceptable quality of life on life-long treatment, providing awareness and avoidance of harmful adverse events, which depend on each TKI safety profile and patient personal background.

Dasatinib discontinuation in patients with chronic-phase chronic myeloid leukemia and stable deep molecular response: the DASFREE study

Treatment-free remission (TFR) in patients with chronic myeloid leukemia in chronic phase (CML-CP) is considered a feasible option, especially with the ability of second-generation tyrosine kinase inhibitors to induce higher rates of sustained deep molecular response (DMR). DASFREE is an open-label, single-arm, multicenter phase II trial assessing TFR after dasatinib discontinuation in patients with CML-CP (N = 84). At 2 years, TFR was 46% in all patients. Multivariate analyses revealed statistically significant associations between 2-year TFR and duration of prior dasatinib (≥median; p = .0051), line of therapy (first line; p = .0138), and age (>65 years; p = .0012). No disease transformation occurred, and the most common adverse events experienced off treatment were musculoskeletal (observed in 30 patients); however, dasatinib withdrawal events were reported in nine patients (11%) by the investigator. Overall, these findings support the feasibility of discontinuing dasatinib for patients with CML-CP in sustained DMR in the first line and beyond.

Combining the Allosteric Inhibitor Asciminib with Ponatinib Suppresses Emergence of and Restores Efficacy against Highly Resistant BCR-ABL1 Mutants

BCR-ABL1 point mutation-mediated resistance to tyrosine kinase inhibitor (TKI) therapy in Philadelphia chromosome-positive (Ph+) leukemia is effectively managed with several approved drugs, including ponatinib for BCR-ABL1T315I-mutant disease. However, therapy options are limited for patients with leukemic clones bearing multiple BCR-ABL1 mutations. Asciminib, an allosteric inhibitor targeting the myristoyl-binding pocket of BCR-ABL1, is active against most single mutants but ineffective against all tested compound mutants. We demonstrate that combining asciminib with ATP site TKIs enhances target inhibition and suppression of resistant outgrowth in Ph+ clinical isolates and cell lines. Inclusion of asciminib restores ponatinib's effectiveness against currently untreatable compound mutants at clinically achievable concentrations. Our findings support combining asciminib with ponatinib as a treatment strategy for this molecularly defined group of patients.

P3110Tyrosine kinase inhibitor nilotinib increases atherosclerosis burden in ApoE knock-out mice

Background

In 2001, imatinib, the 1st generation tyrosine kinase inhibitor (TKI), dramatically improved the treatment and survival of the patients with chronic myeloid leukemia (CML). However, the emergence of imatinib-resistant patients led to the development of 2nd generation TKIs. Nilotinib demonstrated increased efficacy to control CML disease over imatinib and is now recommended as first-line therapy. But arterial occlusive adverse events (AOE) occurs in patients treated with nilotinib and not with imatinib. Mechanisms leading to AOE with nilotinib is not well understood. AOE are dominated by ischemic heart disease and lower extremity arterial disease. Moreover, we demonstrated that CML patients with cardiovascular risk factors are at high risk to rapidly develop AOE with nilotinib.

Purpose

To evaluate the impact of nilotinib in a pre-clinical model of atherosclerosis.

Methods

ApoE Knock-Out mice (8-week-old) were treated with either placebo (N=10), imatinib (IMA) 200mg/kg/day (N=10) or nilotinib (NILO) 100mg/kg/day (N=10) by daily feeding and a high-fat diet for 12 weeks. Heart and aorta were harvested after sacrifice, for histology staining and immunochemistry. Splenocytes were cultured from collected spleens, and Interleukin (IL) 12p70 and IL10 measured by ELISA.

Results

Mice treated with nilotinib showed an increase of atherosclerotic plaque size at the aortic sinus level: 462.1x103 μm2 vs. 344.4x103 μm2 with imatinib or 394.9x103 μm2 with placebo (p<0.05) and at the thoracoabdominal aorta level (p<0.05). Plaques had greater infiltration of macrophages: 33.0±3.4% with nilotinib vs. 7.3±1.3% with imatinib and 12.6±1.1% with placebo (p<0.001) and a larger necrotic nucleus 33.0±3.4% with nilotinib vs. 7.3±1.3% with imatinib or 12.6±1.1% with placebo (p<0.001). Nilotinib modulated the systemic immune response by increasing IL-12p70 and by decreasing IL-10 production by splenocytes after stimulation by LPS-IFNγ whereas IL10 increase was observed with imatinib.

Plaque size (aortic sinus)

Conclusion

Nilotinib has a pro-atherogenic effect in a pre-clinical model of atherosclerosis and increases the monocyte/macrophage pro-inflammatory response. Further experiments are required to identify pathways activated by nilotinib.

P5716Cardioprotective anti inflammatory effects of empaglifozin in doxorubicin induced cardiotoxicity: the role of leukotriene B4 and interleukin 1

Background

Empagliflozin (EMPA), a selective inhibitor of the sodium glucose co-transporter 2 (SGLT2), reduces the risk of hospitalization for heart failure or cardiovascular death in type 2 diabetic patients.

Purpose

We studied the putative cardioprotective and anti-inflammatory effects of EMPA in Doxorubicin (DOXO)-Induced cardiotoxicity.

Methods

For this purpose, we tested the effects of EMPA (at 100 or 500 nM) alone or in combination with DOXO (20 μM) in HL-1 adult cardiomyocytes evaluating: mitochondrial viability, lipid peroxidation (quantifying cellular Malondialdehyde [MDA] and 4-hydroxynonenal [4-HNA]), Leukotriene-B4 expression, p65-NF-κB activation and Interleukin 1β, 8 and 6 secretion. Preclinical studies were also performed in C57BL6 mice, dividing them in 4 groups (n=6): Sham (untreated mice), EMPA (mice treated with EMPA at 10 mg/kg/day, administrated orally for 7 days); DOXO (mice treated with DOXO at 2.25 mg/kg/day, intraperitoneally administered for 7 days); EMPA-DOXO (pre-treatment with EMPA for 3 days and 7 days of co-administration EMPA and DOXO). As predictor of cardiotoxicity, the Global Longitudinal Strain (GLS) was measured using 2D speckle tracking echocardiography. Cardiac lysates were processed for analysis of pro-inflammatory interleukins.

Results

We demonstrated that EMPA, co-incubated with DOXO, increases cardiomyocyte viability of 33,6 and 82% at 100 and 500 nM, respectively (compared to only DOXO treated cells). EMPA inhibits the lipid peroxidation by decreasing MDA and 4-HNA production of around 23,6 and 28,7%, at 100 nM and of 47,8 and 52,1% at 500 nM, respectively, compared to untreated cells (p<0,01 for all). Moreover, EMPA has anti-inflammatory activity reducing the Leukotriene B4 and p65-NFkb expression of 37,4% and 31% at 100 nM and of 58,4 and 64,3% at 500 nM, respectively (all compared to only DOXO treated cells). EMPA also decreased the expression of Interleukin 1β (of 28,5 and 68,8%), Interleukin-8 (of 21,2 and 57,3%) and Interleukin-6 (of 28,1 and 49,8%) at 100 and 500 nM, respectively, compared to only DOXO exposed cells (p<0,05 for all). In our in vivo studies, after 7 days with DOXO, the GLS decreased. Interestingly, in mice treated with EMPA/DOXO, we observed that EMPA prevents the GLS's reduction: GLS was −19.24±1.5 (p<0,01) vs DOXO alone, indicating cardioprotective effects. In DOXO-EMPA groups the cardiac IL-1β, IL-6 and IL-8 were reduced of 48, 54,4 and 58%, compared to only DOXO group (p<0,001 for all).

Conclusion

EMPA has strong anti-inflammatory and cardioprotective effects in DOXO-Induced cardiotoxicity and these effects are mainly mediated by a reduction of the lipid peroxidation, Leukotriene-B4 and NF-κB activation bringing to a strong inhibition of the Interleukin 1β, 8 and 6 production.

P1537Cardiotoxicity induced by the combinatorial treatment based on the immune checkpoint inhibitor pembrolizumab associated to trastuzumab

Background

The immunotherapy has revolutionized the world of oncology in the last decades with considerable advantages in terms of overall survival in cancer patients. A combination therapy based on the co-administration of Pembrolizumab (an antibody against PD-1) and Trastuzumab (the humanized anti-Her2 mAb) was recently proposed in clinical trials for the treatment of Trastuzumab-resistant advanced HER2-positive breast cancer. Although immunotherapies are frequently associated with a wide spectrum of immune-related adverse events, the cardiac toxicity has not been properly studied.

Purpose

We studied, for the first time, the putative cardiotoxic effects of Pembrolizumab associated to Trastuzumab turning the light on the pro-inflammatory effects of this novel combined therapy

Methods

Cell viability, intracellular calcium quantification and pro-inflammatory assays (analyzing the production of Interleukin 1β, 6 and 8 as well as the expression of p65/NFkB and Leukotriene B4) were performed in human fetal cardiomyocytes in vitro. Preclinical studies were also performed in vivo on C57BL6 mice untreated (Sham) or treated with Pembrolizumab and Trastuzumab alone or in combination by analyzing (in cardiac tissue extracts) the same markers of inflammation used in cellular studies.

Results

Combination therapy leads to an increase of the intracellular calcium overload (more than 3 times compared to untreated cells) and to a reduction of the cardiomyocytes viability (of more than 65 and 20–25%, compared to untreated and Pembrolizumab or Trastuzumab treated cells, respectively) thus indicating cardiotoxic effects. Notably, combination therapy increases the inflammation of cardiomyocytes enhancing significantly the production of p65/NFkB and Interleukins. Moreover, in in vivo studies on mice, the association of Pembrolizumab and Trastuzumab shows pro-inflammatory effects in cardiac tissue by stimulating the Interleukin 1β, 8 and 6 expression of 40–50% more than the single treatments; the expression of p65/NFkB and Leukotriene B4 was also increased indicating pro-inflammatory effects.

Conclusion

Combination therapy based on Pembrolizumab associated to Trastuzumab leads to significant cardiac pro-inflammatory effects mediated by overexpression of NFkB/p65 and Leukotriene B4 related pathways

Cardiotoxicity and pro-inflammatory effects of the immune checkpoint inhibitor Pembrolizumab associated to Trastuzumab

BACKGROUND

The immunotherapy has revolutionized the world of oncology in the last decades with considerable advantages in terms of overall survival in cancer patients. The association of Pembrolizumab and Trastuzumab was recently proposed in clinical trials for the treatment of Trastuzumab-resistant advanced HER2-positive breast cancer. Although immunotherapies are frequently associated with a wide spectrum of immune-related adverse events, the cardiac toxicity has not been properly studied.

PURPOSE

We studied, for the first time, the putative cardiotoxic and pro-inflammatory effects of Pembrolizumab associated to Trastuzumab.

METHODS

Cell viability, intracellular calcium quantification and pro-inflammatory studies (analyses of the production of Interleukin 1β, 6 and 8, the expression of NF-kB and Leukotriene B4) were performed in human fetal cardiomyocytes. Preclinical studies were also performed in C57BL6 mice by analyzing fibrosis and inflammation in heart tissues.

RESULTS

The combination of Pembrolizumab and Trastuzumab leads to an increase of the intracellular calcium overload (of 3 times compared to untreated cells) and to a reduction of the cardiomyocytes viability (of 65 and 20-25%, compared to untreated and Pembrolizumab or Trastuzumab treated cells, respectively) indicating cardiotoxic effects. Notably, combination therapy increases the inflammation of cardiomyocytes by enhancing the expression of NF-kB and Interleukins. Moreover, in preclinical models, the association of Pembrolizumab and Trastuzumab increases the Interleukins expression of 40-50% compared to the single treatments; the expression of NF-kB and Leukotriene B4 was also increased.

CONCLUSION

Pembrolizumab associated to Trastuzumab leads to strong cardiac pro-inflammatory effects mediated by overexpression of NF-kB and Leukotriene B4 related pathways.

Effects of transdermal flunixin meglumine on experimentally induced lameness in adult dairy cattle

Lameness is a common animal health condition with significant production and welfare implications. The transdermal formulation of flunixin meglumine is the only approved drug for pain control in cattle in the United States. Thirty adult dairy cows were enrolled in a study to determine the effect of transdermal flunixin on cattle with induced lameness. Cows were allocated to 1 of 3 treatment groups, with 10 cows per group: lameness and flunixin (L+F), lameness and placebo (L+P), or sham induction and placebo (S+P). An arthritis-synovitis was induced in the distal interphalangeal joint of the left hind lateral digit, using 20 mg of amphotericin B, 6 h before the application of treatment. Cows enrolled into the sham induction group had 4 mL of isotonic saline injected into the joint. Cows were dosed with transdermal flunixin at 3.33 mg/kg (1 mL/15 kg), or a placebo at 1 mL/15 kg, every 24 h for 3 d. The first treatment of flunixin or placebo was considered the start of the study, identified as time 0 h. Data were collected from all cows for 120 h following the initial treatment application. Outcome measures included plasma cortisol; substance P; visual lameness assessment; mechanical nociception threshold (MNT), presented as difference between left and right feet; infrared thermography (IRT), presented as difference between left and right feet; and gait analysis using a pressure mat. Cortisol concentrations were lower for the L+F group starting at 1.5 h after drug administration. Substance P levels showed no evidence for treatment differences among groups. Differences between the left hind MNT and right hind MNT were detected, with S+P having the lowest difference at -0.04 kilograms-force (kgf; 95% CI: -1.86 to 1.78 kgf), and L+P having the highest at -2.96 kgf (95% CI: 1.55 to 4.36 kgf). The L+F group was intermediate at -2.08 kgf (95% CI: 0.89 to 3.27 kgf). Similarly, when the difference between the maximum temperatures of the coronary band were examined via IRT, the L+P group had the highest difference at 1.64°C (95% CI: 1.02 to 2.26°C), with the L+F and S+P groups measuring 0.57°C (95% CI: 0.06 to 1.08°C) and 0.53°C (95% CI: -0.2 to 1.25°C) respectively. We found no evidence for differences among treatment groups when analyzing force, contact pressure, step impulse, or stride length. Based on differences in MNT, IRT, and cortisol, transdermal flunixin is an effective analgesic agent for induced lameness. Multiple doses of transdermal flunixin may be required to be clinically effective, based on MNT and IRT data. Further investigation of transdermal flunixin and its analgesic effects is warranted in naturally occurring lameness.

Treatment-free remission with first- and second-generation tyrosine kinase inhibitors

Chronic myeloid leukemia (CML) has become a chronic disease, for which the chronic phase is manageable with tyrosine kinase inhibitor (TKI) therapy. Patients with optimal responses to TKIs have achieved long-term survival, and treatment-free remission (TFR) has since become an additional treatment goal in CML. In this review, we discuss important factors to consider prior to stopping treatment. In addition, published and presented data with the first-generation TKI imatinib, as well as current clinical trials evaluating TFR with the second-generation TKIs dasatinib and nilotinib, are examined. Results obtained outside of clinical trials have been included as well. Because successful TKI discontinuation depends upon accurate BCR-ABL1 monitoring, emerging technologies are also discussed. Clinical data obtained to date indicate that for many patients who achieve deep molecular response (DMR) on TKI therapy, TFR is a safe treatment goal, and, if the response is lost, patients can expect to regain their responses immediately upon reinitiation of TKI. It is also clear that there remains much room for improvement to make TFR a successful reality for most patients. Data from ongoing trials should help refine decisions as to which patients are the best candidates to attempt TKI discontinuation with safe monitoring in place.