Polina Stepensky

Chimeric antigen receptor T (CAR-T) cell therapy has become a standard of care for many hematological malignancies, and has significantly transformed treatment outcomes. However, CAR-T therapy is associated with specific toxicities, including infections. Although the anti-CD19 CAR-T risks are well-characterized, infectious complications following B-cell maturation antigen (BCMA)-directed CAR-T in multiple myeloma (MM) remain under-researched. In this study, we evaluated the incidence and clinical impact of cytomegalovirus (CMV), Epstein–Barr virus (EBV), and adenovirus (ADV) reactivations in 75 patients receiving anti-BCMA CAR-T for MM, and compared them to 60 patients receiving commercial anti-CD19 CAR-T for B-cell lymphoma (BCL). The viral reactivation rates were 20% for CMV and 8% for EBV in the MM group, vs. 31.7% and 3%, respectively, in the BCL group. No ADV reactivations were seen in either cohort. Most of the CMV reactivations (87% in the MM cohort and 68.5% in the BCL cohort) were asymptomatic and clinically insignificant, and had no impact on progression-free survival (PFS) or overall mortality. Overall, these findings suggest that although CMV and EBV reactivations are relatively common after anti-BCMA CAR-T, they are rarely associated with meaningful disease, and the risks do not exceed those of CD19-directed therapy. Thus, routine pre-emptive screening for these viruses may be unwarranted in asymptomatic patients.

Background: B-cell maturation antigen (BCMA)-targeted chimeric antigen receptor T-cell (CAR-T) therapy has demonstrated substantial efficacy in relapsed and/or refractory multiple myeloma. While toxicities such as cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS) have been well characterized, the incidence and clinical consequences of the coagulopathy associated with CRS remain underexplored. Methods: We conducted a prospective analysis of 108 adult patients with multiple myeloma or light chain amyloidosis treated with the academic anti-BCMA CAR-T HBI0101 in a single-center trial (NCT04720313). Coagulopathy was evaluated via serial fibrinogen measurements, with hypofibrinogenemia defined as p < 0.001), number of tocilizumab doses (p < 0.001), peak levels of the inflammation markers LDH (p = 0.001) and ferritin (p = 0.006), and neutropenia (p = 0.33). Five thrombotic events (4.6%) and three minor bleeding events (2.7%) occurred within 3 months post-CAR-T infusion and were not associated with degree of coagulopathy or CRS. No cases of major bleeding or fatal thrombosis occurred. Conclusions: CRS-related coagulopathy is common following BCMA-targeted CAR-T treatment and correlates closely with CRS severity. Despite the high rate of laboratory coagulopathy, thrombosis and bleeding events were infrequent, suggesting the benefit of the prophylactic strategies used.

Background/Objectives: Busulfan is a key component of myeloablative conditioning regimens in hematopoietic stem cell transplantation (HSCT) for pediatric patients with acute myeloid leukemia, solid tumors, and certain non-malignant diseases. This study compares the clinical outcomes of once-daily (BU1) versus four-times-daily (BU4) busulfan dosing regimens in pediatric HSCT recipients. Methods: A retrospective analysis was conducted on 70 pediatric patients who underwent HSCT at Hadassah Medical Center between June 2018 and October 2023. Thirty-five patients received the BU4 regimen, and 35 received BU1. The primary endpoint was 100-day event-free survival (EFS). Results: There was no statistically significant difference in 100-day event-free survival between the BU1 group (88.6%) and the BU4 group (85.7%; p = 0.768). Similarly, no significant differences were found in time to neutrophil engraftment (p = 0.251) or platelet engraftment (p = 0.688). Sinusoidal obstruction syndrome (SOS) occurred in 17.1% of patients in each group. No significant differences were observed in the increase in liver enzyme levels (p = 1.0). The incidence of acute graft-versus-host disease was comparable between the groups (41.9% for BU1 vs. 40.0% for BU4; p = 0.878). Conclusions: Once-daily and four-times-daily busulfan regimens demonstrated comparable clinical outcomes in terms of efficacy and adverse events. Further prospective studies are needed to validate these findings.

HBI0101 is an academic chimeric antigen receptor T-cell (CART)–targeted to B-cell maturation antigen (BCMA) for the treatment of relapsed and refractory multiple myeloma (R/RMM) and light chain amyloidosis. Herein, we present the phase 1b/2 results of 50 heavily pretreated patients with R/RMM dosed with 800 × 106 CART cells. Inclusion criteria were relatively permissive (i.e., performance status and baseline organ function) and consequently, approximately half of the enrolled patients would have been ineligible for pivotal clinical trials. The median time elapsed from patient enrollment until CART delivery was 25 days (range, 14-65). HBI0101-related toxicities included grade 1 to 3 cytokine release syndrome, grade 3 to 4 hematologic toxicities, and grade 1 to 2 immune effector cell–associated neurotoxicity syndrome. Responses were achieved in 90% of the patients, 56% achieved stringent and complete response, and 70% reached a minimal residual disease negativity. Within a median follow-up of 12.3 months, the median progression-free survival (PFS) was 11.0 months (95% confidence interval [CI], 6.2-14.6), and the overall survival was not reached (95% CI, 13.3 to not reached). Multivariable analysis on patient/disease and CART-related characteristics revealed that high-risk cytogenetic, extramedullary disease, and increased number of effector-memory T cells in CART products were independently associated with inferior PFS. In conclusion, comprehensive analyses of the parameters affecting the response to CART therapy are essential for improving patients’ outcome. This trial was registered at www.ClinicalTrials.gov as #NCT04720313.

BACKGROUND. Accurate detection of graft-versus-host disease (GVHD) is a major challenge in the management of patients undergoing hematopoietic stem cell transplantation (HCT). Here, we demonstrated the use of circulating cell-free DNA (cfDNA) for detection of tissue turnover and chronic GVHD (cGVHD) in specific organs. METHODS. We established a cocktail of tissue-specific DNA methylation markers and used it to determine the concentration of cfDNA molecules derived from the liver, skin, lungs, colon, and specific immune cells in 101 patients undergoing HCT. RESULTS. Patients with active cGVHD showed elevated concentrations of cfDNA, as well as tissue-specific methylation markers that agreed with clinical scores. Strikingly, transplanted patients with no clinical symptoms had abnormally high levels of tissue-specific markers, suggesting hidden tissue turnover even in the absence of evident clinical pathology. An integrative model taking into account total cfDNA concentration, monocyte/macrophage cfDNA levels and alanine transaminase was able to correctly identify GVHD with a specificity of 86% and precision of 89% (AUC of 0.8). CONCLUSION. cfDNA markers can be used for the detection of cGVHD, opening a window into underlying tissue dynamics in patients that receive allogeneic stem cell transplants. FUNDING. This work was supported by grants from the Ernest and Bonnie Beutler Research Program of Excellence in Genomic Medicine, The Israel Science Foundation, the Waldholtz/Pakula family, the Robert M. and Marilyn Sternberg Family Charitable Foundation and the Helmsley Charitable Trust (to YD).

Recent studies have highlighted the therapeutic potential of small extracellular bodies derived from mesenchymal stem cells (MSC-sEVs) for various diseases, notably through their ability to alter T-cell differentiation and function. The current study aimed to explore immunomodulatory pathway alterations within T cells through mRNA sequencing of activated T cells cocultured with bone marrow-derived MSC-sEVs. mRNA profiling of activated human T cells cocultured with MSC-sEVs or vehicle control was performed using the QIAGEN Illumina sequencing platform. Pathway networks and biological functions of the differentially expressed genes were analyzed using Ingenuity pathway analysis (IPA)^® software, KEGG pathway, GSEA and STRING database. A total of 364 differentially expressed genes were identified in sEV-treated T cells. Canonical pathway analysis highlighted the RhoA signaling pathway. Cellular development, movement, growth and proliferation, cell-to-cell interaction and inflammatory response-related gene expression were altered. KEGG enrichment pathway analysis underscored the apoptosis pathway. GSEA identified enrichment in downregulated genes associated with TNF alpha and interferon gamma response, and upregulated genes related to apoptosis and migration of lymphocytes and T-cell differentiation gene sets. Our findings provide valuable insights into the mechanisms by which MSC-sEVs implement immunomodulatory effects on activated T cells. These findings may contribute to the development of MSC-sEV-based therapies.