Litzow, Mark R.

Abstract Retrospective studies have suggested that older adolescents and young adults (AYAs) with acute lymphoblastic leukemia (ALL) have better survival rates when treated using a pediatric ALL regimen administered by pediatric treatment teams. To address the feasibility and efficacy of using a pediatric treatment regimen for AYA patients with newly diagnosed ALL administered by adult treatment teams, we performed a prospective study, CALGB 10403, with doses and schedule identical to those in the Children's Oncology Group study AALL0232. From 2007 to 2012, 318 patients were enrolled; 295 were eligible and evaluable for response. Median age was 24 years (range, 17-39 years). Use of the pediatric regimen was safe; overall treatment-related mortality was 3%, and there were only 2 postremission deaths. Median event-free survival (EFS) was 78.1 months (95% confidence interval [CI], 41.8 to not reached), more than double the historical control of 30 months (95% CI, 22-38 months); 3-year EFS was 59% (95% CI, 54%-65%). Median overall survival (OS) was not reached. Estimated 3-year OS was 73% (95% CI, 68%-78%). Pretreatment risk factors associated with worse treatment outcomes included obesity and presence of the Philadelphia-like gene expression signature. Use of a pediatric regimen for AYAs with ALL up to age 40 years was feasible and effective, resulting in improved survival rates compared with historical controls. CALGB 10403 can be considered a new treatment standard upon which to build for improving survival for AYAs with ALL. This trial was registered at www.clinicaltrials.gov as #NCT00558519.

Abstract The plant homeodomain 6 gene (PHF6) is frequently mutated in human T-cell acute lymphoblastic leukemia (T-ALL); however, its specific functional role in leukemia development remains to be established. Here, we show that loss of PHF6 is an early mutational event in leukemia transformation. Mechanistically, genetic inactivation of Phf6 in the hematopoietic system enhances hematopoietic stem cell (HSC) long-term self-renewal and hematopoietic recovery after chemotherapy by rendering Phf6 knockout HSCs more quiescent and less prone to stress-induced activation. Consistent with a leukemia-initiating tumor suppressor role, inactivation of Phf6 in hematopoietic progenitors lowers the threshold for the development of NOTCH1-induced T-ALL. Moreover, loss of Phf6 in leukemia lymphoblasts activates a leukemia stem cell transcriptional program and drives enhanced T-ALL leukemia-initiating cell activity. These results implicate Phf6 in the control of HSC homeostasis and long-term self-renewal and support a role for PHF6 loss as a driver of leukemia-initiating cell activity in T-ALL. Significance: Phf6 controls HSC homeostasis, leukemia initiation, and T-ALL leukemia-initiating cell self-renewal. These results substantiate a role for PHF6 mutations as early events and drivers of leukemia stem cell activity in the pathogenesis of T-ALL. This article is highlighted in the In This Issue feature, p. 305

95 Background: Palliative care (PC) specialists provide supportive care for patients with hematologic diseases (HD). However, the degree of engagement by PC physicians may be limited by the views of both PC physicians & hematologists. Prior studies have surveyed hematologists to identify barriers to delivery of PC, however PC physician views are unclear. This study aimed to examine views of PC physicians toward hematology. Methods: A survey was mailed to a random sample of the AAHPM physician contact list in 2017. Items focused on perceptions of their understanding of HD, comfort providing care, opinions regarding PC & hospice involvement, & beliefs about hematologists. Anonymized responses were assessed on a Likert scale. Statistical testing was based on logistic regression models with generalized estimating equations to account for correlated data within respondents. Results: 538 of 1000 surveys were completed. 51.9% of respondents were male. Community (37.2%), academic (36.7%) & hospice (26.2%) physicians were represented. Respondents were likelier to believe they understand the trajectories of lymphoma & myeloma than leukemia or patients undergoing hematopoietic stem cell transplantation (HSCT) (p < 0.001). They were more comfortable discussing prognosis (p < 0.001) & managing symptoms (p < 0.001) in lymphoma & myeloma than leukemia & HSCT. They were likelier to believe that hematologists’ perceptions of PC physicians limit collaboration rather than their own views of hematologists (p < 0.001). 80.2% agreed that hospice referrals are not made early enough. Conclusions: PC physicians’ understanding of trajectories & comfort caring for patients varies by hematologic disease. They perceive that hematologists’ perceptions are a larger barrier than their own & hospice referrals are delayed. These results provide insights into opportunities for better collaboration with hematologists.

Abstract Therapeutic options for acute lymphoblastic leukemia, especially in the relapsed/refractory setting, have expanded significantly in recent times. However, this comes at the cost of toxicities: medical as well as financial. We highlight some of the unique toxicities associated with the novel agents to apprise our readers about what to expect, how to recognize them, and how to manage these toxicities. One of the toxicities seen with inotuzumab, a CD22 antibody drug conjugate, is sinusoidal obstruction syndrome, which can be fatal in &gt;80% of patients if associated with multiorgan failure. Blinatumomab, a monoclonal antibody targeting CD19, is associated with cytokine release syndrome (CRS) and neurotoxicity, both of which require prompt recognition and management primarily with corticosteroids. CRS and neurotoxicity are more common and more severe with chimeric antigen receptor T-cell therapy (CAR-T). The fact that CAR-T cannot be discontinued on demand adds a layer of complexity to the management of related toxicities of this therapy. Tocilizumab, an interleukin-6 receptor blocker, is used to treat severe CRS from CAR-T, whereas corticosteroids remain the mainstay for neurotoxicity management. Although effective, these drugs carry a high price tag, and we review the available data on cost-effectiveness of these agents, keeping in mind that median follow-up on most of these studies is limited and that long-term data on durability of response remain to be seen.

Abstract Allogeneic hematopoietic cell transplantation (allo-HCT) is a potentially curative treatment of chronic myeloid leukemia (CML). Optimal conditioning intensity for allo-HCT for CML in the era of tyrosine kinase inhibitors (TKIs) is unknown. Using the Center for International Blood and Marrow Transplant Research database, we sought to determine whether reduced-intensity/nonmyeloablative conditioning (RIC) allo-HCT and myeloablative conditioning (MAC) result in similar outcomes in CML patients. We evaluated 1395 CML allo-HCT recipients between the ages of 18 and 60 years. The disease status at transplant was divided into the following categories: chronic phase 1, chronic phase 2 or greater, and accelerated phase. Patients in blast phase at transplant and alternative donor transplants were excluded. The primary outcome was overall survival (OS) after allo-HCT. MAC (n = 1204) and RIC allo-HCT recipients (n = 191) from 2007 to 2014 were included. Patient, disease, and transplantation characteristics were similar, with a few exceptions. Multivariable analysis showed no significant difference in OS between MAC and RIC groups. In addition, leukemia-free survival and nonrelapse mortality did not differ significantly between the 2 groups. Compared with MAC, the RIC group had a higher risk of early relapse after allo-HCT (hazard ratio [HR], 1.85; P = .001). The cumulative incidence of chronic graft-versus-host disease (cGVHD) was lower with RIC than with MAC (HR, 0.77; P = .02). RIC provides similar survival and lower cGVHD compared with MAC and therefore may be a reasonable alternative to MAC for CML patients in the TKI era.