The Superiority of Allogeneic Hematopoietic Stem Cell Transplantation Over Chemotherapy Alone in the Treatment of Acute Myeloid Leukemia Patients with Mixed Lineage Leukemia (MLL) Rearrangements

Outcomes of allogeneic haematopoietic stem cell transplantation for paediatric patients with MLL-rearranged acute myeloid leukaemia

Background

The presence of mixed-lineage leukaemia rearrangement (MLL-r) in paediatric patients with acute myeloid leukaemia (AML) is a poor prognostic predictor. Whether allogeneic haematopoietic stem cell transplantation (allo-HSCT) is beneficial in such cases remains unclear.

Methods

We evaluated the outcomes and prognostic factors of allo-HSCT in 44 paediatric patients with MLL-r AML in the first complete remission (CR1) between 2014 and 2019 at our institution.

Results

For all the 44 patients, the 3-year overall survival (OS), event-free survival (EFS), and cumulative incidence of relapse (CIR) were 74.5%, 64.1%, and 29.1%, respectively. Among them, 37 (84.1%) patients received haploidentical (haplo)-HSCT, and the 3-year OS, EFS, and CIR were 73.0%, 65.6%, and 26.4%, respectively. The 100-day cumulative incidence of grade II–IV acute graft-versus-host disease (aGVHD) post-transplantation was 27.3%, and that of grade III–IV aGVHD was 15.9%. The overall 3-year cumulative incidence of chronic graft-versus-host disease (cGVHD) post-transplantation was 40.8%, and that of extensive cGVHD was 16.7%. Minimal residual disease (MRD)-positive (MRD +) status pre-HSCT was significantly associated with lower survival and higher risk of relapse. The 3-year OS, EFS, and CIR differed significantly between patients with MRD + pre-HSCT (n = 15; 48.5%, 34.3% and 59%) and those with MRD-pre-HSCT (n = 29; 89.7%, 81.4% and 11.7%). Pre-HSCT MRD + status was an independent risk factor in multivariate analysis.

Conclusions

Allo-HSCT (especially haplo-HSCT) can be a viable strategy in these patients, and pre-HSCT MRD status significantly affected the outcomes.

Entospletinib in Combination with Induction Chemotherapy in Previously Untreated Acute Myeloid Leukemia: Response and Predictive Significance of HOXA9 and MEIS1 Expression

PURPOSE

Spleen tyrosine kinase (SYK) signaling is a proposed target in acute myeloid leukemia (AML). Sensitivity to SYK inhibition has been linked to HOXA9 and MEIS1 overexpression in preclinical studies. This trial evaluated the safety and efficacy of entospletinib, a selective inhibitor of SYK, in combination with chemotherapy in untreated AML.

PATIENTS AND METHODS

This was an international multicenter phase Ib/II study, entospletinib dose escalation (standard 3+3 design between 200 and 400 mg twice daily) + 7+3 (cytarabine + daunorubicin) in phase Ib and entospletinib dose expansion (400 mg twice daily) + 7+3 in phase II.

RESULTS

Fifty-three patients (n = 12, phase Ib and n = 41, phase II) with previously untreated de novo (n = 39) or secondary (n = 14) AML were enrolled (58% male; median age, 60 years) in this study. The composite complete response with entospletinib + 7+3 was 70%. Patients with baseline HOXA9 and MEIS1 expression higher than the median had improved overall survival compared with patients with below median HOXA9 and MEIS1 expression. Common adverse events were cytopenias, febrile neutropenia, and infection. There were no dose-limiting toxicities. Entospletinib-related skin rash and hyperbilirubinemia were also observed.

CONCLUSIONS

Entospletinib with intensive chemotherapy was well-tolerated in patients with AML. Improved survival was observed in patients with HOXA9/MEIS1 overexpression, contrasting published data demonstrating poor survival in such patients. A randomized study will be necessary to determine whether entospletinib was a mediator this observation.

Healthcare Costs of Treating Privately Insured Patients with Acute Myeloid Leukemia in the United States from 2004 to 2014: A Generalized Additive Modeling Approach

OBJECTIVES

The primary objective of this study was to predict healthcare cost trajectories for patients with newly diagnosed acute myeloid leukemia (AML) receiving allogeneic hematopoietic cell transplantation (alloHCT), as a function of days since chemotherapy initiation, days relative to alloHCT, and days before death or last date of insurance eligibility (LDE). An exploratory objective examined patients with AML receiving chemotherapy only.

METHODS

We used Optum's de-identified Clinformatics^® Data Mart Database to construct cumulative cost trajectories from chemotherapy initiation to death or LDE (through 31 December 2014) for US patients aged 20-74 years diagnosed between 1 March 2004 and 31 December 2013 (n = 187 alloHCT; n = 253 chemotherapy only). We used generalized additive modeling (GAM) to predict expected trajectories and bootstrapped confidence intervals (CIs) at user-specified intervals conditional on dates of alloHCT and death or LDE relative to chemotherapy initiation.

RESULTS

Expected costs (in 2017 values) for a hypothetical patient receiving alloHCT 60 days after chemotherapy initiation and followed for 5 years were $US572,000 (95% CI 517,000-633,000); $US119,000 (95% CI 51,000-192,000); $US102,000 (95% CI 0-285,000); $US79,000 (95% CI 0-233,000), for years 1-4, respectively, and either $US494,000 (95% CI 212,000-799,000) or $US108,000 (95% CI 0-230,000) in year 5, whether the patient died or was lost to follow-up on day 1825, respectively.

CONCLUSIONS

Rates of cost accrual varied over time since chemotherapy initiation, with accelerations around the time of alloHCT and death. GAM is a potentially useful approach for imputing longitudinal costs relative to treatment initiation and one or more intercurrent, clinical, or terminal events in randomized controlled trials or registries with unrecorded costs or for dynamic decision-analytic models.

The molecular functions of common and atypical MLL fusion protein complexes

Mixed-lineage leukemia (MLL) fuses with a variety of partners to produce a functionally altered MLL complex that is not expressed in normal cells, which transforms normal hematopoietic progenitors into leukemia cells. Because more than 80 fusion partners have been identified to date, the molecular functions of MLL fusion protein complexes appear diverse. However, over the past decade, the common functions utilized for leukemic transformation have begun to be elucidated. It appears that most (if not all) MLL fusion protein complexes utilize the AF4/ENL/P-TEFb and DOT1L complexes to some extent. Based on an understanding of the underlying molecular mechanisms, several molecular targeting drugs are being developed, opening paths to novel therapies. Here, we review the recent progress made in identifying the molecular functions of various MLL fusions and categorize the numerous fusion partners into several functionally-distinct groups to help discern commonalities and differences among various MLL fusion protein complexes.