Breakthrough hemolysis (BTH) is the hemolytic exacerbation occurring in a patient with paroxysmal nocturnal hemoglobinuria (PNH) on treatment with anti-complement therapies. In this review article we analysed 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 patients reported outcomes. In particular, BTH may occur with all complement inhibitors, with a frequency of 10-15% 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 pegcetacoplan treated patients (nearly 24% at 1 year) as compared to 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 about half of cases and modifications of anti-complement therapy included anticipation of the next anti-C5 dose and addition of eculizumab in patients on proximal inhibitors. Breakthrough thromboses were rare, though anti-coagulant prophylaxis should be considered during severe episodes. Complement amplifying conditions were observed in about 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, 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 endpoint was overall survival (OS); key secondary endpoints included complete remission (CR) rate and safety. After randomization of 378 patients, the trial was stopped at a prespecified interim analysis due 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 (HR, 1.178 [95% CI, 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 ineligible for IC. This trial was registered at www.clinicaltrials.gov as #NCT05079230.

DNMT3A mutations in polycythemia vera (PV) patients were heterogenous and not enriched in interferon-alpha (IFN)-treated patients. DNMT3A mutations had no detectable impact on hematologic response, molecular response or survival outcomes.

The antenatal role of the hepcidin-regulating protease Tmprss6 has never been elucidated as knockout dams are infertile. Utilising 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, 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, 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 at 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 genome-wide CRISPR activator screening during mesodermal differentiation from mouse embryonic stem cells (mESCs). Following in vitro differentiation, mesodermal KDR+ precursors were transplanted into primary and secondary immunodeficient NSG mice. This approach led to the identification of seven genes (Spata2, Aass, Dctd, Eif4enif1, Guca1a, Eya2, Net1) that, when activated during mesoderm specification, induce the generation of hematopoietic stem and progenitor cells (HSPCs). 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 seven genes biases the embryoid bodies towards 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 (cBTKi) and/or the B-cell lymphoma 2 (BCL-2) inhibitor 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, non-covalent BTKi pirtobrutinib and CD19-directed chimeric antigen receptor T-cell therapy lisocabtagene maraleucel have both recently gained FDA 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 pre-treated 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 (NCT03624036) is the first prospective trial to evaluate the safety of brexucabtagene autoleucel (previously KTE-X19), a CD19-directed autologous CAR T-cell immunotherapy, in patients with R/R CLL. Patients with ≥2 prior lines of therapy (including a BTK inhibitor) underwent leukapheresis, followed by optional bridging therapy, then conditioning chemotherapy (fludarabine/cyclophosphamide) before infusing 1×106 (Cohort 1) or 2×106 (Cohort 2) anti-CD19 CAR T cells/kg. Patients in Cohort 3 (low tumor burden), and Cohort 4A (ibrutinib pre-treated closely to the apheresis) received 1×106 cells/kg. Fifteen patients, median age 63 years (52-79 years), were treated in Cohort 1 (n=6), Cohort 2 (n=3), Cohort 3 (n=3), and Cohort 4A (n=3). Median follow-up was 24.3 months. One DLT was observed in Cohort 3 (n=1 grade 4 cytokine release syndrome). Grade ≥3 neurologic events occurred in 3 patients (20%). Seven of 15 patients responded (ORR 47%, 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 (ALC) prior to the apheresis. Brexu-cel did not have any new safety signals in R/R CLL, and CAR T-cell expansion and responses occurred in patients with low tumor burden.

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, while 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 "XLT" patients 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 WAS patients to their individual genetic profile, disease severity, and clinical course.

Idecabtagene vicleucel (ide-cel) was the first FDA approved CAR T cell therapy for multiple myeloma. However, as clinical trials are highly selective with stringent eligibility criteria, the objective of this study was to evaluate the safety and effectiveness of standard of care (SOC) ide-cel in the real world. Using the CIBMTR registry we evaluated 821 patients who received SOC ide-cel. Median follow-up was 11.6 months. Median age was 66 years, and the cohort included 31% patients ≥70 years, 15% Black, 7% Hispanic and 77% patients with at least one significant co-morbidity. The median number of prior lines of therapy was 7, 15% patients previously received BCMA-directed therapy, 17% had extramedullary disease and 27% had high-risk cytogenetics. Overall response rate was 73%, and complete response (CR) rate was 25%. Median progression-free survival was 8.8 months. Treatment-related mortality was reported in 6% of patients. Cytokine release syndrome was diagnosed in 80% of patients (grade >=3: 3%). Immune effector cell associated neurotoxicity syndrome was observed in 28% (grade >=3: 5%), with no cases of Parkinsonism reported. Clinically significant infections were seen in 45% of patients. Second primary malignancies were reported in 4%, including 1% myeloid malignancies. This is the largest real-world study of ide-cel CAR-T cell therapy in pts with RRMM. We observed a favorable safety and efficacy profile that mirrors trial experience, even in the setting of significant co-morbidities in 77% of patients, many of which would have made them ineligible for the registrational KarMMa clinical trial.

Acalabrutinib is a Bruton tyrosine kinase inhibitor approved for treatment of chronic lymphocytic leukemia. We present results from ELEVATE-TN (NCT02475681) after median follow-up of 74.5 months. Overall, 535 patients were randomized (acalabrutinib-obinutuzumab, n = 179; acalabrutinib, n = 179; chlorambucil-obinutuzumab, n = 177). Median age was 70 years, 63.0% had unmutated IGHV (uIGHV), 13.6% had del(17p) and/or mutated TP53, and 17% had complex karyotype (CK; ≥3 chromosomal abnormalities). Median progression-free survival (PFS) was not reached (NR) for acalabrutinib-obinutuzumab and acalabrutinib vs 27.8 months for chlorambucil-obinutuzumab (both P < .0001); estimated 72-month overall PFS rates were 78.0%, 61.5%, and 17.2%, respectively. Acalabrutinib-obinutuzumab resulted in improved PFS vs acalabrutinib monotherapy (hazard ratio [HR]: 0.58, P = .0229). Patients with uIGHV, del(17p) and/or mutated TP53, or CK had significantly improved PFS with acalabrutinib ± obinutuzumab vs chlorambucil-obinutuzumab (P < .0001, P ≤ .0009, and P < .0001 for both acalabrutinib-containing arms, respectively). Median overall survival (OS) was NR for all treatments, with significantly longer OS for acalabrutinib-obinutuzumab vs chlorambucil-obinutuzumab (HR: 0.62, P = .0349). Estimated 72-month OS rates were 83.9%, 75.5%, and 74.7% for acalabrutinib-obinutuzumab, acalabrutinib, and chlorambucil-obinutuzumab, respectively. Adverse events (AEs) occurring after >4 years were mostly grade 1-2. Rates of AEs, serious AEs, and events of clinical interest were similar between acalabrutinib-containing arms and consistent with the known safety profiles of acalabrutinib and obinutuzumab. Efficacy and safety of acalabrutinib-containing arms were maintained, with longer PFS in both acalabrutinib arms vs chlorambucil-obinutuzumab including in patients with high-risk features.