BACKGROUND: β-Thalassemia is an inherited hemolytic disease that is prevalent worldwide. Over 200 mutations in the HBB gene, which encodes adult hemoglobin (HbA), result in β-thalassemia. Hereditary persistence of fetal hemoglobin (HbF) can alleviate the symptoms of anemia. CRISPR-Cas9-mediated disruption of the BCL11A erythroid enhancer results in the reduction of BCL11A expression and the induction of fetal γ-globin, which is a practicable therapeutic strategy for treating transfusion-dependent β-thalassemia (TDT). METHODS: We obtained mobilized autologous CD34+ cells from 4 TDT patients sponsor initiated in phase I/II clinical trial (NCT05577312) and 6 TDT patients in investigator initiated clinical study（NCT04211480, NCT04205435）respectively. These cells were edited with CRISPR-Cas9 RNP at the +58 erythroid specific enhancer region of the BCL11A gene and then reinfused after the patients had undergone myeloablative busulfan conditioning. We subsequently monitored adverse events, neutrophil and platelet engraftment. Efficacy assessments included proportion of transfusion-independent (TI) subjects, levels of total hemoglobin and HbF, and proportion of red blood cells expressing HbF in peripheral blood. TI was evaluated for elimination of transfusions starting 42 days after the last transfusion and Hb above 90 g/L. RESULTS: Between October 15, 2019 and November 20, 2022, 10 patients with TDT were enrolled and received BRL-101 with a median age of 12.4 years (6-26). Among all the treated patients, 5 patients were β 0/β 0 phenotype, 4 patients were β0/β+ phenotype and 1 patient were β +/β + phenotype. As of July 20, 2023, the median follow- up was 24.6 months (4.3-39.2 m) (Tab.1). All of 10 patients achieved TI. The median duration of TI was 22.1 months (1.3 - 37.2 m). The longest duration of TI was 37.2 months (Fig.1). The levels of HbF ranged from 2.3 to 140.7g/L and the levels of total hemoglobin ranged from 105.7 to 149 g/L (Fig.2). At 6 months after BRL-101 infusion, the proportion of HbF-expressing red blood cells in peripheral blood had reached 96.5%, and then continued to rise and remained around 98-99% (Fig.3). Treatment-related adverse events were typical of those associated with myeloablation and autologous stem-cell transplantation, mainly manifested as hematological toxicities (Tab.2, Tab.3). 3 patients experienced adverse events (AEs) grade ≥ 3 which related to BRL-101. 4 patients experienced serious AEs (SAEs), including decreased platelet count, shock, febrile infection, soft tissue infection, and veno-occlusive liver disease. Only decreased platelet count may related to BRL-101, the others were due to busulfan treatment. All the SAEs were resolved. No study drug-related withdrawals or deaths occurred during treatment. CONCLUSIONS: Whether genotype was β 0/β 0 or non-β 0/β 0, BRL-101 demonstrated clinically meaningful increases in total Hb and HbF which occurred early and have been maintained over time, the safety profile of BRL-101 is generally consistent with that of myeloablative conditioning and autologous hematopoietic stem cell transplant. The updated data with 10 patients reported here are consistent with previous reports and support continued investigation of BRL-101 as a potential functional cure for patients with TDT.

Belumosudil is a selective small molecule inhibitor of Rho-associated coiled-coil kinase 2 (ROCK2) indicated for patients with glucocorticoid-refractory chronic graft-versus-host disease (cGVHD). Despite its approval for ages 12-18, there is limited pediatric data available. This case series presents three 12-year-old patients with severe cGVHD who had failed multiple lines of therapy. Case #1 received treatment for 210 days with belumosudil, prednisone, cyclosporine A, mycophenolate mofetil, and ruxolitinib. Initial assessments showed skin and joint fascia involvement (National Institutes of Health score 3), along with oral cavity, ocular, and pulmonary involvement (score 2). Following treatment, all affected organs demonstrated at least a partial response (PR), with an overall assessment of PR. Case #2 was treated for 205 days with belumosudil, tacrolimus, and ruxolitinib. Baseline assessments indicated involvement of the skin and joint fascia (score 3), and the oral cavity and eyes (score 2). Most organs achieved PR or complete response (CR), resulting in an overall PR. Case #3 underwent 121 days of therapy with belumosudil, prednisone, and tacrolimus, showing similar baseline organ involvement as Case #2. The treatment resulted in an overall PR, with improvement noted in the skin, oral cavity, eyes, and joint fascia. The Lee cGVHD symptom scale scores improved meaningfully for all patients over time. There was no recurrence of the primary disease or any fatalities. Adverse events were limited to grade 1-2 severity. This case series indicates that belumosudil may be effective in 12-year-old pediatric patients with severe, multi-organ cGVHD refractory to multiple treatments. The findings suggest that belumosudil-based regimens can be feasible and well-tolerated in this population, providing preliminary evidence for its potential therapeutic effects in clinical management.

Dear Editor, Haploidentical allogeneic hematopoietic stem cell transplantation (haplo-HSCT),a curative therapy for severe aplastic anemia (SAA) patients,has been used clinically for decades.Two models,not involving ex vitro T-cell depletion,have been adopted for haplo-HSCT in patients with SAA.The first is referred to as the "Beijing protocol" (Xu et al.,2017),and comprises a conditioning regimen using busulfex (BU),cyclophosphamide (CY),and anti-thymocyte globulin (ATG) followed by granulocyte colony-stimulating factor (G-CSF)-primed bone marrow (BM) and/or peripheral blood (PB) hematopoietic stem cells (HSCs).The second is a recently developed,post-transplant cyclophosphamide (PTCY)-based protocol (Clay et al.,2014).To date,there have been no studies to determine the better one for haploHSCT in patients with acquired SAA.