Chronic myeloid leukemia (CML) has served as a paradigm for the development of effective initial and next-generation targeted therapies. The availability of 5 effective and generally well-tolerated BCR::ABL1 tyrosine kinase inhibitors for the treatment of newly diagnosed chronic-phase CML offers patients and their treating physicians a welcome luxury of choice. The long-term outlook for patients with newly diagnosed chronic-phase CML is excellent, with expected survival similar to age-matched controls. However, most patients are expected to require lifelong treatment. As a result, important considerations when choosing frontline treatment include not only treatment efficacy but also response durability, tolerability, maximizing quality of life, avoidance of serious and irreversible toxicities, the ease of treatment administration, and, increasingly, the cost of treatment to the patient as well as to society.

Chronic granulomatous disease (CGD) is an inborn error of immunity that is caused by defects in any 1 of the 5 subunits (gp91phox, p47phox, p22phox, p67phox, p40phox) that form the NAD phosphate oxidase complex 2 (NOX2) or in the chaperone protein essential for reactive oxygen species (ROS) that supports its assembly. These defects lead to severely reduced phagocyte-derived ROS production. Almost 50% of patients with CGD have inflammatory bowel disease (IBD) associated with dysbiosis, and the age of IBD onset may vary according to the CGD genotype. Although we previously demonstrated that the intestinal microbiota determines colitis susceptibility in CGD mice, the underlying mechanisms remain unknown. We hypothesized that NOX2 defects are associated with distinct intestinal microbiome signatures and immune responses, which impact colitis severity. Chemical colitis susceptibility was evaluated in 2 strains of CGD mice (gp91phox-/- and p47phox-/-) with distinct microbiotas from 2 different animal facilities, while also evaluating the impact of microbiota standardization and colitogenic microbiota transfer on mucosal immune responses at the intestinal barrier. Although p47phox-/- and gp91phox-/- mice that harbored a colitogenic microbiota had increased colitis severity, the intestinal epithelial cells from p47phox-/- mice produced more ROS, which was associated with increased NOX isoform gene expression. In contrast, gp91phox-/- mice had decreased mucin production and a mucosal immune response profile suggestive of increased inflammasome activation at the intestinal barrier when compared with control and p47phox-/- mice. Our findings suggest that the microbiota impacts colitis susceptibility in a CGD genotype-specific manner, thereby potentially explaining differences in the timing of IBD onset in patients with different CGD genotypes and identifying potential novel and personalized therapeutic targets.

Richter transformation (RT) is defined as an aggressive lymphoma emerging in patients with chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL). Despite novel therapeutics developed in CLL, RT is associated with poor outcomes. In light of recent progress regarding the diagnostic procedures and therapeutic concepts of RT, an international group of experts, under the coordination of the European Research Initiative on CLL, has developed consensus recommendations for clinical procedures and future research on this disease. Patients with RT typically present with a rapid clinical decline, worsening B-symptoms, elevated lactate dehydrogenase, and/or rapidly enlarging lymphadenopathy. Workup should include a positron emission tomography-computed tomography scan for patients with suspected RT. An excisional biopsy should be taken from an accessible lesion, preferably with the highest fluorodeoxyglucose avidity, and analyzed for the presence of aggressive lymphoma. The molecular relationship to the original CLL clone(s) should be defined. Because no effective standard treatment for RT exists, patients should be treated in a clinical trial. Response of both RT and CLL should be assessed at an early time point, and survival end points should be prioritized in trial design. We hope that these recommendations can help to harmonize clinical and translational research and improve outcomes for patients with RT.

This study reports outcomes of Pediatric Leukemia Adoptive Therapy 02 (PLAT-02), a phase 2 trial of SCRI-CAR19, a second-generation chimeric antigen receptor (CAR) T-cell product with FMC63 single-chain variable fragment and 4-1BB costimulation, in pediatric and young adult patients with B-cell acute lymphoblastic leukemia; and PLAT-03, a companion study evaluating exogenous CD19 antigen stimulation with serial infusions of T cells expressing truncated CD19, T-cell antigen-presenting cells (T-APCs). The efficacy cohort of PLAT-02 (n = 72 patients; median age 12.5 years) received fludarabine/cyclophosphamide lymphodepletion followed by a dose of 1 × 106 CAR+ T cells per kg. The minimal residual disease-negative complete remission rate was 89%. Leukemia-free survival (LFS) at 1 and 2 years was 0.71 (95% confidence interval [CI], 0.58-0.81) and 0.64 (95% CI, 0.51-0.75), respectively. Patients with low disease burden had significantly higher 1-year LFS (0.91 vs 0.42). Rapid in vivo contraction of CAR T cells after infusion was associated with CAR loss within 6 months compared to those without rapid contraction (57% vs 19%). Most common grade 3/4 adverse events included cytokine release syndrome in 13% and neurotoxicity in 16%. The companion pilot, PLAT-03, enrolled 26 patients, and 19 received T-APCs. Neither cytokine-release syndrome nor neurotoxicity was observed after T-APC infusion. T-APC infusions in patients improved persistence (P = .03), with rapid CAR T-cell contraction being associated with decreased early CAR loss (20% with T-APC vs 57% without). Further exploration of serial artificial CD19 antigen exposure is warranted based on these pilot results. PLAT-02 and PLAT-03 trials were registered at www.clinicaltrials.gov as #NCT02028455 and #NCT03186118, respectively.

Breakthrough hemolysis (BTH) is the hemolytic exacerbation occurring in a patient with paroxysmal nocturnal hemoglobinuria (PNH) on treatment with anticomplement therapies. In this review article, we analyzed the definition, frequency, and severity of BTH events across phase 3 clinical trials with terminal (anti-C5 ravulizumab and crovalimab) and complement inhibitors upstream C5 (anti-C3 pegcetacoplan, alternative-pathway inhibitors iptacopan, and danicopan), as well as from real-world reports. Furthermore, we reviewed the impact of the various compounds on quality of life and patient-reported outcomes. In particular, BTH may occur with all complement inhibitors, with a frequency of 10% to 15% over 6 months with eculizumab, crovalimab, and pegcetacoplan, and <5% with ravulizumab, iptacopan, and danicopan plus anti-C5. By prolonging the follow-up, the frequency of BTH appeared increased in patients treated with pegcetacoplan (nearly 24% at 1 year) as compared with both anti-C5, iptacopan, and double inhibition with danicopan plus anti-C5. BTH risk appears associated with patients' features, particularly suboptimal response/failure of previous complement inhibitor. Transfusions were required in approximately half of cases and modifications of anticomplement therapy included anticipation of the next anti-C5 dose and addition of eculizumab in patients on proximal inhibitors. Breakthrough thromboses were rare, although anticoagulant prophylaxis should be considered during severe episodes. Complement amplifying conditions were observed in approximately half of cases and were more frequently infections. Treatment adherence, optimization of the administration schedule, anticoagulant prophylaxis, as well as education of patients and physicians remain important factors to prevent BTH and its complications.

Patients with acute myeloid leukemia (AML) ineligible for intensive chemotherapy (IC) have limited treatment options. The phase 3 ENHANCE-3 study aimed to determine whether magrolimab (magrolimab arm) was superior to placebo (control arm) when either was combined with venetoclax and azacitidine. Adults with previously untreated AML who were ineligible for IC were randomized to receive magrolimab (1 mg/kg on days 1 and 4, 15 mg/kg on day 8, 30 mg/kg on days 11 and 15, then weekly for 5 weeks, and then every 2 weeks) or placebo, venetoclax (100 mg on day 1, 200 mg on day 2, and 400 mg daily thereafter), and azacitidine (75 mg/m2 days 1-7) in 28-day cycles. The primary end point was overall survival (OS); key secondary end points included complete remission (CR) rate and safety. After randomization of 378 patients, the trial was stopped at a prespecified interim analysis owing to futility. At final analysis, with median follow-up of 7.6 months (magrolimab arm) vs 7.4 months (control arm), median OS was 10.7 vs 14.1 months (hazard ratio, 1.178; 95% confidence interval, 0.848-1.637). The CR rate within 6 cycles was 41.3% vs 46.0%. Addition of magrolimab to venetoclax and azacitidine resulted in more fatal adverse events (19.0% vs 11.4%), primarily driven by grade 5 infections (11.1% vs 6.5%) and respiratory events (2.6% vs 0%). There were similar incidences of any-grade infections, febrile neutropenia, and neutropenia between arms. These results highlight the difficulty in improving outcomes for patients with AML who were ineligible for IC. This trial was registered at www.clinicaltrials.gov as #NCT05079230.

DNMT3A mutations in patients with polycythemia vera were heterogeneous and not enriched in interferon alfa-treated patients. DNMT3A mutations had no detectable impact on the hematologic response, molecular response, or survival outcomes.

The antenatal role of the hepcidin-regulating protease Tmprss6 has never been elucidated because knockout dams are infertile. Using an in vivo knockdown approach, we confirm Tmprsss6 is critical for hepcidin suppression in pregnancy, and Tmprss6 inhibition drives deleterious fetal outcomes.

Hereditary stomatocytosis represents a heterogeneous group of inherited erythrocyte membrane defects characterized by hemolytic anemia of variable degree, with alterations in cellular salt and water, ranging from dehydration to overhydration, and the presence of stomatocytes on peripheral blood smear. This condition encompasses various subtypes, each with distinct clinical and genetic features. The pathophysiology underlying these conditions involves altered red blood cell membrane properties, leading to impaired deformability and alterations in cation permeability and volume, causing increased susceptibility to hemolysis. Advancements in genetic testing have enabled the identification of some causative genes in the last years, such as PIEZO1, KCNN4, and ABCB6. These genetic discoveries have facilitated a deeper understanding of the molecular mechanisms underlying the pathogenesis and have paved the way for improved diagnostic accuracy and genetic counseling. This review provides an overview of the clinical presentation, pathophysiology, molecular genetics, diagnosis, and management strategies of hereditary stomatocytosis, highlighting recent advancements in the field of dehydrated hereditary stomatocytosis (DHS), or hereditary xerocytosis, and hepatic iron overload. This latter is directly associated with the physiological role of PIEZO1, the causative gene of DHS, at hepatic and macrophagic levels. Particularly, gain-of-function mutations in PIEZO1 account for a pleiotropic syndrome characterized by different phenotypes depending on the expression of PIEZO1 in multiple cells and tissues.

Hematopoietic stem cells (HSCs) possess the ability to long term reconstitute all the blood lineages and generate all blood cell types. As such, the in vitro generation of HSCs remains a central goal in regenerative medicine. Despite many efforts and recent advancements in the field, there is still no robust, reproducible, and efficient protocol for generating bona fide HSCs in vitro. This suggests that certain regulatory elements have yet to be uncovered. Here, we present a novel and unbiased approach to identifying endogenous components to specify HSCs from pluripotent stem cells. We performed a genomewide CRISPR activator screening during mesodermal differentiation from mouse embryonic stem cells. After in vitro differentiation, mesodermal KDR+ precursors were transplanted into primary and secondary immunodeficient NSG mice. This approach led to the identification of 7 genes (Spata2, Aass, Dctd, Eif4enif1, Guca1a, Eya2, and Net1) that, when activated during mesoderm specification, induce the generation of hematopoietic stem and progenitor cells. These cells are capable of serial engraftment and multilineage output (erythroid, myeloid, and T and B lymphoid) in vivo. Single-cell RNA sequencing further revealed that activating these 7 genes biases the embryoid bodies toward intraembryonic development, instead of extraembryonic, increasing the number of mesodermal progenitors that can generate HSCs. Our findings underscore the importance of differentiation during the first germ layer specification to generate definitive blood stem cells.

Targeted therapy with covalent Bruton tyrosine kinase inhibitors (cBTKis) and/or the B-cell lymphoma 2 inhibitor (BCL-2i) venetoclax is now well established in the first-line management of chronic lymphocytic leukemia (CLL). However, patients with "double-refractory" disease due to the acquired resistance to both drug classes represent an increasing clinical challenge for whom few well-tolerated and effective treatment options currently exist. The highly selective, noncovalent BTKi pirtobrutinib and CD19-directed chimeric antigen receptor T-cell therapy lisocabtagene maraleucel have both recently gained US Food and Drug Administation approval for use in patients with CLL, which has progressed following ≥2 prior lines, including a cBTKi and a BCL-2i. Additionally, novel BTK-directed therapies and T-cell-engaging bispecific antibodies have achieved promising responses in pretreated CLL in early-phase clinical trials. Here, we review the mechanisms responsible for resistance to cBTKi and venetoclax in CLL, appraise recent evidence supporting the use of each of the novel and emerging agent classes, and then suggest innovative treatment strategies incorporating these in patients with double-refractory disease, remaining cognizant of the variability of access to novel therapies and clinical trials.

ZUMA-8 evaluated the safety of brexucabtagene autoleucel (brexu-cel), a CD19-directed autologous chimeric antigen receptor (CAR) T-cell immunotherapy, for patients with relapsed/refractory chronic lymphocytic leukemia (R/R CLL). Patients with ≥2 prior lines of therapy (including a Bruton tyrosine kinase inhibitor) underwent leukapheresis, optional bridging therapy, and conditioning chemotherapy (fludarabine/cyclophosphamide) before infusion of 1 × 106 (cohort 1) or 2 × 106 (cohort 2) anti-CD19 CAR T cells per kg. Patients in cohort 3 (low tumor burden), and cohort 4A (postibrutinib) received 1 × 106 cells per kg. Fifteen patients, median age of 63 years (range, 52-79), were treated in cohorts 1 (n = 6), 2 (n = 3), 3 (n = 3), and 4A (n = 3). Median follow-up was 24.3 months. One dose-limiting toxicity was observed in cohort 3 (grade 4 cytokine release syndrome). Grade ≥3 neurologic events occurred in 3 patients (20%). Seven of 15 patients responded (overall response rate, 47%; complete response [CR], 7%), including all 3 patients in cohort 3 (1 with CR). CAR T-cell expansion occurred in 4 patients (27%), with an apparent weak inverse correlation with absolute lymphocyte count before apheresis. Brexu-cel had no new safety signals in R/R CLL. CAR T-cell expansion and responses occurred in patients with low tumor burden. This trial was registered at www.clinicaltrials.gov as #NCT03624036.

Wiskott-Aldrich syndrome (WAS) is a rare X-linked disorder, characterized by thrombocytopenia, eczema, recurrent infections, autoimmunity, and malignancy. Here, we discuss current conservative and definitive approaches to treating WAS, based on recently published evidence. Disease severity in WAS is highly variable. Recent studies confirm that the probability of disease progression depends on the type of genetic variant, supporting early diagnosis and tailored treatment strategies. Milder cases, historically termed X-linked thrombocytopenia (XLT), received supportive care, whereas severe cases were referred for standard allogeneic hematopoietic cell transplantation (HCT) or gene therapy (GT) in clinical trials. Advances in HCT and GT, together with recent knowledge that even patients with XLT are at risk for severe immune complications, suggest that most young patients with WAS should be offered a potentially curative approach at diagnosis. Older patients with a small subset of milder variants may be treated conservatively unless they develop life-threatening autoimmune or malignant complications; regular monitoring and proactive management are critical to preventing irreversible complications. We recommend discontinuing the term XLT as it implies a mild and uncomplicated disease, which is not the norm, and instead tailor treatment for all patients with WAS to their individual genetic profile, disease severity, and clinical course.