Comparable Results Between 8 and 12 Gray TBI in Combination With Fludarabine and Post-Transplant Cyclophosphamide in MRD-Negative but Not in MRD-Positive Acute Lymphoblastic Leukemia Patients Transplanted in First Complete Remission.

BACKGROUND: The optimal TBI dose for ALL patients undergoing allogeneic SCT is still not clearly defined. METHODS: Single-center retrospective analysis of high-risk ALL patients in CR1 treated with 8 Gy (n = 22) or 12 Gy (n = 50) TBI in combination with fludarabine and PTCy. Median patient age in the 8 Gy TBI cohort was 63 (37-79) and 37 (18-56) in the 12 Gy TBI cohort and median follow-up time was 21 months (range 1-92). RESULTS: OS and LFS at 2 years after 8 Gy were 65% and 55% versus 74% and 74% after 12 Gy (p = 0.3 and p = 0.2, respectively). CIR and NRM at 2 years were 27% and 14% after 8 Gy versus 4% and 20% after 12 Gy (p = 0.004 and p = 0.4, respectively). MRD-positive (+) patients (n = 26) receiving 12 Gy (n = 19) showed better OS (p = 0.01), LFS (p = 0.009), GRFS, lower CIR (p = 0.02), and similar NRM than did MRD+ patients receiving 8 Gy (n = 7). MRD-negative (-) patients (n = 38) receiving 12 Gy (n = 27) had similar OS, LFS, GRFS, lower CIR, and higher NRM (p = 0.04) than did MRD- patients receiving 8 Gy (n = 11). CONCLUSION: Our study demonstrates that 8 Gy TBI in comparison to 12 Gy TBI results in low NRM but a high relapse rate with similar OS, LFS, and GRFS. In MRD+ high-risk ALL patients, allogeneic SCT with 12 Gy TBI leads to improved OS, LFS, GRFS, and a low relapse rate. Prospective studies comparing the different treatment regimens with larger MRD patient cohorts are needed to confirm this data.

Splenic irradiation for myelofibrosis prior to hematopoietic cell transplantation: A global collaborative analysis.

Splenomegaly is the clinical hallmark of myelofibrosis. Splenomegaly at the time of allogeneic hematopoietic cell transplantation (HCT) is associated with graft failure and poor graft function. Strategies to reduce spleen size before HCT especially after failure to Janus kinase (JAK) inhibition represent unmet clinical needs in the field. Here, we leveraged a global collaboration to investigate the safety and efficacy of splenic irradiation as part of the HCT platform for patients with myelofibrosis. We included 59 patients, receiving irradiation within a median of 2 weeks (range, 0.9-12 weeks) before HCT. Overall, the median spleen size prior to irradiation was 23 cm (range, 14-35). Splenic irradiation resulted in a significant and rapid spleen size reduction in 97% of patients (57/59), with a median decrease of 5.0 cm (95% confidence interval, 4.1-6.3 cm). The most frequent adverse event was thrombocytopenia, with no correlation between irradiation dose and hematological toxicities. The 3-year overall survival was 62% (95% CI, 48%-76%) and 1-year non-relapse mortality was 26% (95% CI, 14%-38%). Independent predictors for survival were severe thrombocytopenia and anemia before irradiation, transplant-specific risk score, higher-intensity conditioning, and present portal vein thrombosis. When using a propensity score matching adjusted for common confounders, splenic irradiation was associated with significantly reduced relapse (p = .01), showing a 3-year incidence of 12% for splenic irradiation versus 29% for patients with immediate HCT and 38% for patients receiving splenectomy. In conclusion, splenic irradiation immediately before HCT is a reasonable approach in patients experiencing JAK inhibition failure and is associated with a low incidence of relapse.

CD19-targeted chimeric antigen receptor T cell therapy in two patients with multiple sclerosis.

BACKGROUND: Progressive multiple sclerosis (MS) is characterized by compartmentalized smoldering neuroinflammation caused by the proliferation of immune cells residing in the central nervous system (CNS), including B cells. Although inflammatory activity can be prevented by immunomodulatory therapies during early disease, such therapies typically fail to halt disease progression. CD19 chimeric antigen receptor (CAR)-T cell therapies have revolutionized the field of hematologic malignancies. Although generally considered efficacious, serious adverse events associated with CAR-T cell therapies such as immune effector cell-associated neurotoxicity syndrome (ICANS) have been observed. Successful use of CD19 CAR-T cells in rheumatic diseases like systemic lupus erythematosus and neuroimmunological diseases like myasthenia gravis have recently been observed, suggesting possible application in other autoimmune diseases. METHODS: Here, we report the first individual treatment with a fully human CD19 CAR-T cell therapy (KYV-101) in two patients with progressive MS. FINDINGS: CD19 CAR-T cell administration resulted in acceptable safety profiles for both patients. No ICANS was observed despite detection of CD19 CAR-T cells in the cerebrospinal fluid. In case 1, intrathecal antibody production in the cerebrospinal fluid decreased notably after CAR-T cell infusion and was sustained through day 64. CONCLUSIONS: CD19 CAR-T cell administration in progressive MS resulted in an acceptable safety profile. CAR-T cell presence and expansion were observed in the cerebrospinal fluid without clinical signs of neurotoxicity, which, along with intrathecal antibody reduction, indicates expansion-dependent effects of CAR-T cells on CD19+ target cells in the CNS. Larger clinical studies assessing CD19 CAR-T cells in MS are warranted. FUNDING: Both individual treatments as well the generated data were not based on external funding.

Graft-versus-host disease and impact on relapse in myelofibrosis undergoing hematopoietic stem cell transplantation.

Allogeneic hematopoietic stem cell transplantation (alloHSCT) remains the only curative treatment for myelofibrosis (MF). Relapse occurs in 10-30% and remains a major factor for dismal outcomes. Previous work suggested that graft-versus-host disease (GVHD) might be associated with risk of relapse. This study included 341 patients undergoing their first (n = 308) or second (n = 33) alloHSCT. Anti-T-lymphocyte or antithymocyte globulin was used for GVHD prophylaxis in almost all patients. Median time to neutrophile and platelet engraftment was 13 days and 19 days, respectively. The cumulative incidence of acute GVHD grade II-IV was 41% (median, 31 days; range, 7-112). Grade III-IV acute GVHD was observed in 22%. The cumulative incidence of chronic GVHD was 61%. Liver was affected in 23% of acute GVHD cases and 46% of chronic GVHD cases. Severe acute GVHD was associated with high non-relapse mortality. The development of acute GVHD grade II and moderate GVHD was an independent factor for reduced risk for relapse after transplantation without increased risk for non-relapse mortality, while especially acute GVHD grade IV was associated with high non-relapse mortality. Last, we identified that ongoing response to ruxolitinib, accelerated-phase MF at time of transplantation and splenectomy prior to transplantation were independent predictors for relapse.

Anti-T-lymphocyte globulin improves GvHD-free and relapse-free survival in myelofibrosis after matched related or unrelated donor transplantation.

Acute and chronic graft-versus-host disease (GvHD) are major complications of allogeneic hematopoietic cell transplantation (alloHCT). In vivo T-cell depletion with anti-T-lymphocyte globulin (ATLG) as part of the conditioning regimen prior to alloHCT is frequently used as GvHD prophylaxis, but data on its role in myelofibrosis is scarce. We took advantage of an international collaborative network to investigate the impact of ATLG in myelofibrosis undergoing first alloHCT. We included 707 patients (n = 469 ATLG and n = 238 non-ATLG prophylaxis). The cumulative incidence of acute GvHD grade II-IV was 30% for the ATLG group vs. 56% for the non-ATLG group (P < 0.001). Acute GvHD grade III-IV occurred in 20% vs. 25%, respectively (P = 0.01). Incidence of mild-to-severe chronic GvHD was 49% vs. 50% (P = 0.52), while ATLG showed significantly lower rates of severe chronic GvHD (7% vs. 18%; P = 0.04). GvHD-free and relapse-free survival (GRFS) at 6 years was 45% for the ATLG group vs. 37% for the non-ATLG group (P = 0.02), driven by significantly improved GRFS of ATLG in matched related and matched unrelated donors. No significant differences in risk for relapse, non-relapse mortality, and overall survival were observed. Multivariable modeling for GRFS showed a 48% reduced risk of GvHD, relapse, or death when using ATLG.

Anti-T-lymphocyte globulin (ATLG) compared to post-transplant cyclophosphamide as GvHD prophylaxis in ALL patients undergoing allogeneic stem cell transplantation.

We retrospectively analyzed high-risk ALL patients in CR1 receiving total body irradiation based conditioning regimen with ATLG (n = 74) or PTCy (n = 73) for GVHD prophylaxis. The 3-year OS and LFS were similar in both groups: 65 and 60% in the ATLG group and 64 and 67% in the PTCy group (p = 0.9 and 0.5, respectively). CIR and NRM rate at three years was 12 and 21% after PTCy and 19 and 20% after ATLG (p = 0.4 and p = 0.9, respectively). Acute GvHD grades II-IV and grades III/IV at 100 days was 46 and 19% after PTCy and 33 and 10% after ATLG (p = 0.08 and p = 0.9, respectively). Chronic GvHD of all grade at two years was higher after PTCy: 55% versus 26% (p < 0.001). Based on the propensity score matching (PSM) analysis, aGvHD grades II-IV was trending higher in the PTCy group compared to the ATLG group (p = 0.07). In contrast to the PSM analysis, on multivariate analysis the receipt of PTCy compared with ATLG was associated with a reduced CIR (p = 0.026). Our retrospective single-center analysis shows a lower incidence of acute and chronic GvHD while displaying similar LFS and OS after ATLG compared to PTCy in TBI based allogeneic stem cell transplantation for high-risk ALL.

Development and Validation of a Prediction Model of Outcome After B-Cell Maturation Antigen-Directed Chimeric Antigen Receptor T-Cell Therapy in Relapsed/Refractory Multiple Myeloma.

PURPOSE: Although chimeric antigen receptor T therapy (CAR-T) cells are an established therapy for relapsed/refractory multiple myeloma (RRMM), there are no established models predicting outcome to identify patients who may benefit the most from CAR-T. PATIENTS AND METHODS: This is an international retrospective observational study including patients with RRMM infused with currently available commercial or academically produced anti-B-cell maturation antigen (BCMA) CAR-T. We describe characteristics and outcomes in Europe (n = 136) and the United States (n = 133). Independent predictors of relapse/progression built a simple prediction model (Myeloma CAR-T Relapse [MyCARe] model) in the training cohort (Europe), which was externally validated (US cohort) and tested within patient- and treatment-specific subgroups. RESULTS: The overall response rate was 87% and comparable between both cohorts, and complete responses were seen in 48% (Europe) and 49% (the United States). The median time to relapse was 5 months, and early relapse <5 months from infusion showed poor survival across cohorts, with the 12-month overall survival of 30% (Europe) and 14% (the United States). The presence of extramedullary disease or plasma cell leukemia, lenalidomide-refractoriness, high-risk cytogenetics, and increased ferritin at the time of lymphodepletion were independent predictors of early relapse or progression. Each factor received one point, forming the three-tiered MyCARe model: scores 0-1 (low risk), scores 2-3 (intermediate risk), and a score of 4 (high risk). The MyCARe model was significantly associated with distinct 5-month incidence of relapse/progression (P < .001): 7% for low-risk, 27% for intermediate-risk, and 53% for high-risk groups. The model was validated in the US cohort and maintained prognostic utility for response, survival, and outcomes across subgroups. CONCLUSION: Outcomes of patients with RRMM after CAR-T are comparable between Europe and the United States. The MyCARe model may facilitate optimal timing of CAR-T cells in patient-specific subgroups.

Norfluoxetine inhibits TREK-2 K2P channels by multiple mechanisms including state-independent effects on the selectivity filter gate.

The TREK subfamily of two-pore domain K+ (K2P) channels are inhibited by fluoxetine and its metabolite, norfluoxetine (NFx). Although not the principal targets of this antidepressant, TREK channel inhibition by NFx has provided important insights into the conformational changes associated with channel gating and highlighted the role of the selectivity filter in this process. However, despite the availability of TREK-2 crystal structures with NFx bound, the precise mechanisms underlying NFx inhibition remain elusive. NFx has previously been proposed to be a state-dependent inhibitor, but its binding site suggests many possible ways in which this positively charged drug might inhibit channel activity. Here we show that NFx exerts multiple effects on single-channel behavior that influence both the open and closed states of the channel and that the channel can become highly activated by 2-APB while remaining in the down conformation. We also show that the inhibitory effects of NFx are unrelated to its positive charge but can be influenced by agonists which alter filter stability, such as ML335, as well as by an intrinsic voltage-dependent gating process within the filter. NFx therefore not only inhibits channel activity by altering the equilibrium between up and down conformations but also can directly influence filter gating. These results provide further insight into the complex allosteric mechanisms that modulate filter gating in TREK K2P channels and highlight the different ways in which filter gating can be regulated to permit polymodal regulation.