Treatment approach and outcomes of patients with accelerated/blast-phase myeloproliferative neoplasms in the current era.

Progression of myeloproliferative neoplasms (MPNs) to accelerated or blast-phase is associated with poor survival outcomes. Since 2017 there have been several therapies approved for use in acute myeloid leukemia (AML); these therapies have been incorporated into the management of accelerated/blast-phase MPNs (MPN-AP/BP). We performed a multi-center analysis to investigate outcomes of patients diagnosed with MPN-AP/BP in 2017 or later. Two-hundred two patients were identified; median overall survival (OS) was 0.86 years. We also analyzed patients based on first-line treatment; the three most common approaches were intensive chemotherapy (IC) (n=65), DNA methyltransferase inhibitor (DNMTi)-based regimens (n=65), and DNMTi + venetoclax (VEN)-based regimens (n=54). Median OS was not significantly different by treatment type. In addition, we evaluated response by 2017 European LeukemiaNet (ELN) AML criteria and 2012 MPN-BP criteria in an effort to understand the association of response with survival outcomes. We also analyzed outcomes in 65 patients that received allogeneic hematopoietic stem cell transplant (allo-HCT); median OS was 2.30 years from time of allo-HCT. Our study demonstrates that survival amongst patients with MPN-AP/BP is limited in the absence of allo-HCT even in the current era of therapeutics and underscores the urgent need for new agents and approaches.

Evaluating the efficacy and toxicity of dose adjusted pegylated L-asparaginase in combination with therapeutic drug monitoring.

The incorporation of pediatric-inspired regimens in the adolescent-young-adult (AYA) and adult populations have resulted improved survival outcomes (Stock et al. Blood 133(14):1548-1559 2019; Dunsmore et al. J Clin Oncol 38(28):3282-3293 2020; DeAngelo et al. Leukemia 29(3):526-534 2015). Nonetheless incorporation of such regimens is limited by increased toxicity to asparaginase. Dosing strategies that reduce the weight-based dose of pegylated-L-asparaginase (PEG-asparaginase) utilizing activity monitoring have been shown to result in better tolerability of these regimens. The purpose of this study was to analyze the efficacy and safety of treating adults with Philadelphia chromosome negative (Ph-) ALL with pediatric-inspired regimens that incorporate PEG-asparaginase dose adjustments and asparaginase activity level monitoring. Patients aged 18-65 years initiated on pediatric-inspired regimens utilizing dose-reduced PEG-asparaginase with therapeutic drug monitoring-guided adjustments were included. The screening of 122 patients treated between 2015 and 2021 resulted in the inclusion of 54 patients. The median age of the cohort was 35 years (16-65 years), and median body mass index (BMI) was 30 kg/m2 (18.3-53.4 kg/m2). The 36-month survival estimate was 62.1% (95% CI 48.1-77.7%), and the median overall survival (OS) was 62.2 months (95% CI 35.1-89.3 months). In the AYA cohort, the 36-month survival was 71.2% (95% CI 55.8-91%) and the median overall survival was not reached. Survival was not significantly affected by immunophenotype or BMI. Discontinuation due to toxicity or hypersensitivity reactions was low at 11% and 9% respectively. The encouraging survival outcomes and favorable tolerability of this older population in the real-world setting support the use of individualized PEG-asparaginase dosing with PharmD-guided therapeutic drug monitoring.

Solving coagulation conundrums: comparing prophylaxis strategies in adult patients receiving PEG-asparaginase.

PEG-asparaginase is a key component in treatment regimens for acute lymphoblastic leukemia (ALL). Major side effects include thrombosis and bleeding; however, there is currently no consensus on methods to prevent these complications. In this multi-center retrospective cohort study of 101 adults, we compared two prophylaxis strategies: cryoprecipitate and fresh frozen plasma (Cryo/FFP) versus cryoprecipitate and antithrombin (ATIII). The overall incidence of venous thromboembolism (VTE) was not significantly different between the two groups (19.7% for Cryo/FFP and 8.6% in Cryo/ATIII, p = 0.17), and neither was grade ≥3 bleeding (3% for Cryo/FFP and 11.4% for Cryo/ATIII, p = 0.18). Given the significant cost associated with ATIII without a clear benefit, a careful benefit and risk analysis should be considered before utilizing ATIII as a prophylaxis strategy to prevent thrombosis or bleeding following asparaginase administration.

Efficacy and safety of avapritinib in previously treated patients with advanced systemic mastocytosis.

Advanced systemic mastocytosis (AdvSM) is a rare myeloid neoplasm, driven by the KIT D816V mutation in >90% of patients. Avapritinib, a potent, highly selective D816V-mutant KIT inhibitor, is approved for treatment of adults with AdvSM by the US Food and Drug Administration, regardless of prior therapy, and the European Medicines Agency for patients with prior systemic therapy, based on EXPLORER (#NCT02561988; clinicaltrials.gov) and PATHFINDER (#NCT03580655; clinicaltrials.gov) clinical studies. We present latest pooled efficacy and safety analyses from patients who received ≥1 systemic therapy prior to avapritinib in EXPLORER/PATHFINDER. Overall response rate in response-evaluable patients (n = 31) was 71% (95% confidence interval: 52% to 86%; 22/31), including 19% (6/31) with complete remission (CR)/CR with partial recovery of peripheral blood counts (CRh). Median time to response was 2.3 months, median time to CR/CRh was 7.4 months, and median duration of response (DOR) was not reached. Reductions ≥50% in bone marrow mast cell infiltration (89%), KIT D816V variant allele fraction (66%), serum tryptase (89%), and reductions ≥35% in spleen size (70%) occurred in most patients. Median OS was not reached (median follow-up 17.7 months). Avapritinib was effective in all AdvSM subtypes, regardless of number/type of prior therapies or poor prognostic somatic mutations. Treatment-related adverse events (TRAEs) were observed in 94% of patients, most commonly grade 1/2; 57% had TRAEs of at least grade 3; 81% remained on treatment at 6 months. Avapritinib in adults with AdvSM who received prior systemic therapy was generally well tolerated, with high response rates regardless of prior systemic therapy.

Efficacy and safety of avapritinib in advanced systemic mastocytosis: interim analysis of the phase 2 PATHFINDER trial.

Advanced systemic mastocytosis (AdvSM) is a rare, KIT D816V-driven hematologic neoplasm characterized by mast cell infiltration and shortened survival. We report the results of a prespecified interim analysis of an ongoing pivotal single-arm phase 2 trial (no. NCT03580655 ) of avapritinib, a potent, selective KIT D816V inhibitor administered primarily at a once-daily starting dose of 200 mg in patients with AdvSM (n = 62). The primary endpoint was overall response rate (ORR). Secondary endpoints included mean baseline change in AdvSM-Symptom Assessment Form Total Symptom Score and quality of life, time to response, duration of response, progression-free survival, overall survival, changes in measures of disease burden and safety. The primary endpoint was successfully met (P = 1.6 × 10-9), with an ORR of 75% (95% confidence interval 57-89) in 32 response-evaluable patients with AdvSM who had sufficient follow-up for response assessment, including 19% with complete remission with full or partial hematologic recovery. Reductions of ≥50% from baseline in serum tryptase (93%), bone marrow mast cells (88%) and KIT D816V variant allele fraction (60%) were observed. The most frequent grade ≥3 adverse events were neutropenia (24%), thrombocytopenia (16%) and anemia (16%). Avapritinib demonstrated a high rate of clinical, morphological and molecular responses and was generally well tolerated in patients with AdvSM.

Utility of methicillin-resistant Staphylococcus aureus (MRSA) nasal screening in patients with acute myeloid leukemia (AML).

BACKGROUND: Current literature has demonstrated the utility of the MRSA nasal screen as a de-escalation tool to decrease unnecessary anti-MRSA antibiotic therapy. However, data on the applicability of this test in patients with hematologic malignancy is lacking. METHODS: This is a single-center, retrospective cohort study of patients with acute myeloid leukemia (AML) with or without a history of hematopoietic cell transplant (HCT), with pneumonia and MRSA nasal screening with respiratory cultures obtained. The primary outcome was to determine the negative predictive value (NPV) of the MRSA nasal screen for MRSA pneumonia. Secondary outcomes included sensitivity, specificity, positive predictive value (PPV) of the MRSA nasal screen and prevalence of MRSA pneumonia. RESULTS: Of 98 patients with AML and pneumonia, the prevalence of MRSA pneumonia was 4.1% with confirmed positive MRSA respiratory cultures observed in 4 patient cases. In patients with confirmed MRSA pneumonia, 3 had positive MRSA nasal screens while 1 had a false negative result, possibly due to a long lag time (21 days) between MRSA nasal screen and pneumonia diagnosis. Overall, the MRSA nasal screen demonstrated 75% sensitivity and 100% specificity, with a PPV of 100% and a NPV of 98.9%. CONCLUSIONS: Given the low prevalence, empiric use of anti-MRSA therapy in those AML and HCT patients with pneumonia may not be warranted in clinically stable patients. For patients in whom empiric anti-MRSA antibiotics are initiated, nasal screening for MRSA may be utilized to de-escalate anti-MRSA antibiotics in patients with AML with or without HCT.

Impact of high dose cytarabine dosing strategies in obese patients with acute myeloid leukemia.

High dose cytarabine (HIDAC) consolidation has demonstrated a survival benefit in patients with acute myeloid leukemia (AML). The increasing prevalence of obesity and the toxicity risk with this therapy renders important the quantification of potential risks with weight-based dosing in this patient population. The American Society of Clinical Oncology published recommendations on chemotherapy dosing in obese patients, but patients with leukemia were excluded from analysis. This was a retrospective comparison of safety and efficacy outcomes in obese and non-obese patients with AML who received HIDAC consolidation. Thirty-nine (41.9 %) patients received dose adjusted HIDAC in cycle 1. Nine of the 40 patients in the obese group received HIDAC dose-adjusted for obesity. The combined incidence of cycle delays, febrile neutropenia, or documented infection was 41.5 % in non-obese patients compared to 57.5 % in obese patients (p = 0.127). The median overall survival (OS) and event free survival (EFS) were not reached in both cohorts. The estimated 36-month overall survival was 76.4 % (95 % CI 0.623-0.905) in non-obese patients, compared to 66.1 % (95 % CI 0.472-0.85) in obese patients. There were no significant differences in safety or efficacy outcomes for obese versus non-obese patients who received HIDAC consolidation. For class III obesity, baseline dose-adjustments were more common.

Flotetuzumab as salvage immunotherapy for refractory acute myeloid leukemia.

Approximately 50% of acute myeloid leukemia (AML) patients do not respond to induction therapy (primary induction failure [PIF]) or relapse after <6 months (early relapse [ER]). We have recently shown an association between an immune-infiltrated tumor microenvironment (TME) and resistance to cytarabine-based chemotherapy but responsiveness to flotetuzumab, a bispecific DART antibody-based molecule to CD3ε and CD123. This paper reports the results of a multicenter, open-label, phase 1/2 study of flotetuzumab in 88 adults with relapsed/refractory AML: 42 in a dose-finding segment and 46 at the recommended phase 2 dose (RP2D) of 500 ng/kg per day. The most frequent adverse events were infusion-related reactions (IRRs)/cytokine release syndrome (CRS), largely grade 1-2. Stepwise dosing during week 1, pretreatment dexamethasone, prompt use of tocilizumab, and temporary dose reductions/interruptions successfully prevented severe IRR/CRS. Clinical benefit accrued to PIF/ER patients showing an immune-infiltrated TME. Among 30 PIF/ER patients treated at the RP2D, the complete remission (CR)/CR with partial hematological recovery (CRh) rate was 26.7%, with an overall response rate (CR/CRh/CR with incomplete hematological recovery) of 30.0%. In PIF/ER patients who achieved CR/CRh, median overall survival was 10.2 months (range, 1.87-27.27), with 6- and 12-month survival rates of 75% (95% confidence interval [CI], 0.450-1.05) and 50% (95% CI, 0.154-0.846). Bone marrow transcriptomic analysis showed that a parsimonious 10-gene signature predicted CRs to flotetuzumab (area under the receiver operating characteristic curve = 0.904 vs 0.672 for the European LeukemiaNet classifier). Flotetuzumab represents an innovative experimental approach associated with acceptable safety and encouraging evidence of activity in PIF/ER patients. This trial was registered at www.clinicaltrials.gov as #NCT02152956.

Successful use of blinatumomab in a patient with acute lymphoblastic leukemia and severe hepatic dysfunction.

Relapsed/refractory acute lymphoblastic leukemia poses a significant clinical challenge due to its poor prognosis, with survival rates of less than a year, even with novel therapies. Patients frequently experience toxicities from induction chemotherapy such as hepatotoxicity, which can limit therapeutic options upon relapse. Blinatumomab, a novel immunotherapy, has demonstrated excellent efficacy in relapsed/refractory acute lymphoblastic leukemia; however, there are limited data on use of this agent in patients with significant organ dysfunction. In this report, we describe the safe and effective use of blinatumomab in an adult patient with refractory Philadelphia chromosome-negative (Ph-) acute lymphoblastic leukemia in the setting of severe hepatic dysfunction. Blinatumomab may represent a viable option to treat relapsed/refractory acute lymphoblastic leukemia in patients with significant hepatic dysfunction.

The leukemia strikes back: a review of pathogenesis and treatment of secondary AML.

Secondary AML is associated with a disproportionately poor prognosis, consistently shown to exhibit inferior response rates, event-free survival, and overall survival in comparison with de novo AML. Secondary AML may arise from the evolution of an antecedent hematologic disorder, or it may arise as a complication of prior cytotoxic chemotherapy or radiation therapy in the case of therapy-related AML. Because of the high frequency of poor-risk cytogenetics and high-risk molecular features, such as alterations in TP53, leukemic clones are often inherently chemoresistant. Standard of care induction had long remained conventional 7 + 3 until its reformulation as CPX-351, recently FDA approved specifically for secondary AML. However, recent data also suggests relatively favorable outcomes with regimens based on high-dose cytarabine or hypomethylating agents. With several investigational agents being studied, the therapeutic landscape becomes even more complex, and the treatment approach involves patient-specific, disease-specific, and therapy-specific considerations.