Beckman, Amy

Abstract Little is known about the central nervous system (CNS) risk in high-grade B-cell lymphoma, not otherwise specified (HGBL NOS). Hence, we sought to describe the rates of baseline CNS involvement, risk of CNS recurrence after primary therapy, and management strategies in HGBL NOS. In this multicenter retrospective study, we included 160 adults with newly diagnosed HGBL NOS treated between 2016 and 2021 at 20 US institutions. Eleven patients (7%) had baseline CNS involvement at diagnosis (leptomeningeal = 6, parenchymal = 4, and both = 1). Baseline CNS involvement was significantly associated only with MYC rearrangement (OR = 3.5) and testicular (in men) or female pelvic (in women) involvement (OR = 8.1). There was no significant difference in survival outcomes between patients with HGBL NOS with (median PFS = 4 years) or without (median PFS = 2.4 years) baseline CNS involvement (P = 0.45). The cumulative incidence of CNS recurrence at 3 years was 11%. Patients with baseline CNS involvement were at the highest risk (48.5% vs 8% for those without baseline CNS involvement) and were excluded from the risk factors analysis for CNS recurrence. The risk for CNS recurrence was significantly associated with blood or bone marrow involvement, CD5 expression, non–germinal center B-cell subtype, and “dual-expresser lymphoma” phenotype, however, high CNS IPI was not. The prognosis of relapsed HGBL NOS was poor, regardless of whether recurrence was systemic or limited to the CNS, and with currently available salvage strategies, including autologous transplantation and chimeric antigen receptor T-cell modalities, almost all patients with CNS recurrence ultimately succumbed to their disease.

Context Gene editing–based therapies are currently in development in the areas of oncology, inherited disease, and infectious disease. These potentially life-altering therapies are derived from decades of research in both academic and industry settings that developed technologies rooted in principles and products of nature. However, with such technologic developments come many important considerations, including adverse risks, high cost, and ethical questions. Objective To educate pathologists about gene editing technologies, inform them of potential indications and risks, outline regulatory and practical issues that could affect hospital-based practice and laboratory testing, and advocate that pathologists need to be present at discussions among industry and regulators pertaining to gene editing–based therapies. Design A Gene Editing Workgroup, facilitated by the College of American Pathologists Personalized Health Care Committee and consisting of pathologists of various backgrounds, was convened to develop an educational paper to serve as a stimulus to increase pathologist involvement and inquiry in gene editing therapeutic and diagnostic implementation. Results Through multiple discussions and literature review, the workgroup identified potential gaps in pathologists' knowledge of gene editing. Additional topics that could impact pathology and laboratory medicine were also identified and summarized in order to facilitate pathologists as stakeholders in gene editing therapy administration and monitoring and potential use in diagnostics. Conclusions Gene editing therapy is a complex but potentially transformative area of medicine. This article serves as an introduction to pathologists to assist them in future discussions with colleagues and potentially identify and alter pathology practices that relate to gene editing.

Abstract In this multi-institutional retrospective study, we examined the characteristics and outcomes of 160 patients with high-grade B-cell lymphoma, not otherwise specified (HGBL-NOS)—a rare category defined by high-grade morphologic features and lack of MYC rearrangements with BCL2 and/or BCL6 rearrangements ("double hit"). Our results show that HGBL-NOS tumors are heterogeneous: 83% of patients had a germinal center B-cell immunophenotype, 37% a dual-expressor immunophenotype (MYC and BCL2 expression), 28% MYC rearrangement, 13% BCL2 rearrangement, and 11% BCL6 rearrangement. Most patients presented with stage IV disease, a high serum lactate dehydrogenase, and other high-risk clinical factors. Most frequent first-line regimens included dose-adjusted cyclophosphamide, doxorubicin, vincristine, and etoposide, with rituximab and prednisone (DA-EPOCH-R; 43%); rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP; 33%); or other intensive chemotherapy programs. We found no significant differences in the rates of complete response (CR), progression-free survival (PFS), or overall survival (OS) between these chemotherapy regimens. CR was attained by 69% of patients. PFS at 2 years was 55.2% and OS was 68.1%. In a multivariable model, the main prognostic factors for PFS and OS were poor performance status, lactate dehydrogenase >3 × upper limit of normal, and a dual-expressor immunophenotype. Age >60 years or presence of MYC rearrangement were not prognostic, but patients with TP53 alterations had a dismal PFS. Presence of MYC rearrangement was not predictive of better PFS in patients treated with DA-EPOCH-R vs R-CHOP. Improvements in the diagnostic criteria and therapeutic approaches beyond dose-intense chemotherapy are needed to overcome the unfavorable prognosis of patients with HGBL-NOS.

Introduction. Myeloid leukemia in children with Down syndrome (ML-DS) is a unique subtype of acute myeloid leukemia, distinguished by an earlier age of onset (under 4 years of age); somatic mutations of GATA1; hypersensitivity of leukemic blasts to cytarabine and other chemotherapeutic agents; lack of CNS involvement; and superior event-free survival (EFS, 85-90% at 5 years). Due to these excellent outcomes, successive protocols by the Children's Oncology Group (COG) have aimed for a reduction of treatment intensity but continue to include a course containing high-dose cytarabine (HD-AraC) for all patients, which is associated with the bulk of infectious toxicity. COG AAML1531 is the first study to evaluate differential treatment for ML-DS patients based on risk-stratification. We report the outcomes for patients with Standard Risk (SR) ML-DS enrolled on AAML1531, who were treated without inclusion of HD-AraC (https://clinicaltrials.gov/ct2/show/NCT02521493?term=AAML1531&rank=1). Methods. Patients older than 90 days and younger than 4 years of age with ML-DS were eligible, including those presenting with myelodysplastic syndrome (< 20% blasts in the bone marrow) and trisomy 21 mosaicism. Pathological and cytogenetic data were reviewed centrally. All patients received the same first course of induction therapy (cytarabine 200 mg/m2/24h IV as continuous infusion, day 1-4; daunorubicin 20 mg/m2IV, day 1-4; thioguanine 50 mg/m2/dose PO twice daily, day 1-4; and a single dose of age-based intrathecal cytarabine on day 1). After this first course, measureable residual disease (MRD) in the bone marrow by multi-dimensional flow cytometry in a reference laboratory was used for risk stratification. Patients with negative MRD (<0.05%) were assigned to Standard Risk (SR) therapy, which was modeled after the AAML0431 predecessor study, but with further reduction of treatment by omission of the course containing HD-AraC/E. coli asparaginase (Induction II of AAML0431). Courses #2 and #3 of SR therapy were identical to the first course except that no further intrathecal chemotherapy was administered. Courses #4 and #5 (cytarabine 100 mg/m2/24h IV as continuous infusion day 1-7; etoposide 125 mg/m2 IV, day 1-3) were identical to the corresponding courses of AAML0431. For patients younger than 36 months, chemotherapy doses were calculated based on weight. Use of dexrazoxane during anthracycline-containing courses was at the discretion of the treating center but was captured by the data collection of the study. Patients with positive MRD (>0.05%) after the first course were assigned to the High Risk (HR) Arm and received intensified therapy (equivalent to that used for non-DS AML). Accrual to the HR arm is ongoing. Results. Interim analysis of SR therapy was performed after 50% of expected EFS events had occurred as of June 30, 2018. The observed EFS was 89.3 +/- 6.1% at 2 years from study entry and significantly lower than expected for comparable MRD-negative patients whose treatment in predecessor study AAML0431 included a course of HD-AraC/E. coliasparaginase (p=0.0002). OS at 2 years was 88.7 +/- 6.8%. Among a total of 114 SR ML-DS patients, 11 developed a relapse, all within the first year from study entry (range 136-327 days). OS at 1 year from relapse was 9.1 +/- 17.3%. Based on the results of interim analysis, the SR arm of AAML1531 was closed to accrual due to lack of efficacy. Cytogenetic analysis showed that complex karyotypes (defined as >3 independent abnormalities including >1 structural one) were significantly more frequent in SR patients who relapsed (40%, n=10) compared to SR patients who did not (9%; n=100; p=0.017). The most common abnormalities were trisomies (61% of cases) of chromosomes 3 and 8, and a gain of a fourth copy of chromosome 21. Monosomy 7 was present in 20% of relapsed vs. 5% of patients without a relapse (p=0.122). Conclusions. MRD measured by multi-dimensional flow cytometry is insufficient to identify a subset of ML-DS patients for whom HD-AraC/E.coliasparaginase can be eliminated from treatment. Cytogenetic profiling may aid in further refining risk-based subsets of ML-DS patients. Additional approaches to risk stratification of ML-DS should be pursued, which take into account the emerging genetic events that co-operate with mutant GATA1 in the development of ML-DS. At this time, HD-AraC/E.coli asparaginase should be included in the treatment of ML-DS, regardless of MRD. Disclosures Druley: Washington University: Employment; ArcherDX Inc.: Employment, Equity Ownership. Loken:Hematologics, Inc: Employment, Equity Ownership. Eidenschink Brodersen:Hematologics, Inc: Employment.