Citations

AbstractThe challenge of disease relapsed/refractory (R/R) remains a therapeutic hurdle in chimeric antigen receptor (CAR) T‐cell therapy, especially for hematological diseases, with chronic lymphocytic leukemia (CLL) being particularly resistant to CD19 CAR T cells. Currently, there is no approved CAR T‐cell therapy for CLL patients. In this study, we aimed to address this unmet medical need by choosing the B‐cell activating factor receptor (BAFF‐R) as a promising target for CAR design against CLL. BAFF‐R is essential for B‐cell survival and is consistently expressed on CLL tumors. Our research discovered that BAFF‐R CAR T‐cell therapy exerted the cytotoxic effects on both CLL cell lines and primary B cells derived from CLL patients. In addition, the CAR T cells exhibited cytotoxicity against CD19‐knockout CLL cells that are resistant to CD19 CAR T therapy. Furthermore, we were able to generate BAFF‐R CAR T cells from small blood samples collected from CLL patients and then demonstrated the cytotoxic effects of these patient‐derived CAR T cells against autologous tumor cells. Given these promising results, BAFF‐R CAR T‐cell therapy has the potential to meet the long‐standing need for an effective treatment on CLL patients.

Abstract Unirradiated patients with relapsed/refractory (R/R) B-cell non-Hodgkin lymphoma (NHL) who undergo anti-CD19 chimeric antigen receptor T-cell therapy (CART) have a predominant localized pattern of relapse, the significance of which is heightened in individuals with limited/localized disease before CART. This study reports on the outcomes of patients with R/R NHL and limited (<5 involved sites) disease bridged with or without radiotherapy. A multicenter retrospective review of 150 patients with R/R NHL who received CART with <5 disease sites before leukapheresis was performed. Bridging treatment, if any, was administered between leukapheresis and CART infusion. Study end points included relapse-free survival (RFS), event-free survival (EFS), and overall survival. Before CART infusion, 48 patients (32%) received bridging radiotherapy (BRT), and 102 (68%) did not. The median follow-up was 21 months. After CART infusion, BRT patients had higher objective response (92% vs 78%; P = .046) and sustained complete response rates (54% vs 33%; P = .015). Local relapse in sites present before CART was lower in the BRT group (21% vs 46%; P = .003). BRT patients had improved 2-year RFS (53% vs 44%; P = .023) and 2-year EFS (37% vs 34%; P = .039) compared with patients who did not receive BRT. The impact of BRT was most prominent in patients who had ≤2 pre-CART involved disease sites, with 2-year RFS of 62% in patients who received BRT compared with 42% in those who did not (P = .002). BRT before CART for patients with limited (<5 involved disease sites) R/R NHL improves response rate, local control, RFS, and EFS without causing significant toxicities.

Abstract We evaluate the impact of donor types on outcomes of hematopoietic cell transplantation (HCT) in myelofibrosis, using the Center for International Blood and Marrow Transplant Research registry data for HCTs done between 2013 and 2019. In all 1597 patients, the use of haploidentical donors increased from 3% in 2013 to 19% in 2019. In study-eligible 1032 patients who received peripheral blood grafts for chronic-phase myelofibrosis, 38% of recipients of haploidentical HCT were non-White/Caucasian. Matched sibling donor (MSD)–HCTs were associated with superior overall survival (OS) in the first 3 months (haploidentical hazard ratio [HR], 5.80 [95% confidence interval (CI), 2.52-13.35]; matched unrelated (MUD) HR, 4.50 [95% CI, 2.24-9.03]; mismatched unrelated HR, 5.13 [95% CI, 1.44-18.31]; P < .001). This difference in OS aligns with lower graft failure with MSD (haploidentical HR, 6.11 [95% CI, 2.98-12.54]; matched unrelated HR, 2.33 [95% CI, 1.20-4.51]; mismatched unrelated HR, 1.82 [95% CI, 0.58-5.72]). There was no significant difference in OS among haploidentical, MUD, and mismatched unrelated donor HCTs in the first 3 months. Donor type was not associated with differences in OS beyond 3 months after HCT, relapse, disease-free survival, or OS among patients who underwent HCT within 24 months of diagnosis. Patients who experienced graft failure had more advanced disease and commonly used nonmyeloablative conditioning. Although MSD-HCTs were superior, there is no significant difference in HCT outcomes from haploidentical and MUDs. These results establish haploidentical HCT with posttransplantation cyclophosphamide as a viable option in myelofibrosis, especially for ethnic minorities underrepresented in the donor registries.

7038 Background: While chimeric antigen receptor T-cell (CAR-T) therapy has transformed treatment for hematological malignancies, severe (≥ grade 3,Gr 3, CTCAE) cytopenias post CAR-T and therapy related myeloid neoplasms (t-MN) are particularly difficult to manage. Survival after diagnosis of t-MN is dismal. Management of ≥Gr 3 cytopenias that do not recover by month 3 after CAR-T require frequent monitoring and transfusion support. Growth factor and thrombopoietin mimetics have variable success, with stem cell boost emerging as having more consistent success. Evaluation for CAR-T eligibility, prior to leukapheresis, is the critical timepoint where factors identified at this time could inform risks and benefits of CAR-T versus alternative treatment and for consideration of stem cell collection in patients who may benefit from stem cell boost to treat severe cytopenia post CAR-T. Methods: We conducted a retrospective analysis comparing clinical data of patients (pts) with lymphoma (NHL) and multiple myeloma (MM) treated with FDA-approved and investigational CAR-T between 01/2016 – 06/2022 at Mayo Clinic. Prolonged cytopenias were defined as hemoglobin (Hg)<8 g/dL, absolute neutrophil count (ANC)<0.5 x 109/L, and/or platelet count (PLT)<50 x 109/L at 3 months after CAR-T. Pts with progressive disease were excluded from cytopenia analysis. Logistic regression to identify factors correlated with cytopenia and t-MN. Results: Among the 186 pts who received CAR-T, 42 (22%) patients developed severe cytopenia (26/102, 25%, in NHL; 16/84, 19% in MM); 15/186 (8%) had more than 1 concurrent cytopenia. Univariate analysis identified that baseline ferritin and CAR-HEMATOTOX score correlated with cytopenia. Multivariate analysis showed that advanced age (≥ 65 years) (HR 2.69, 95%CI 1.17 – 6.40, P = 0.02) and thrombocytopenia (HR 4.01, 95%CI 1.77 – 9.34, P = 0.001) were associated with severe cytopenia. Twenty (10.7%) patients [8 (40%) males] developed t-MN at a median of 9.5 months (IQR 4.8 – 19.3 months) after CAR-T (14/102, 13% in NHL; 6/84, 7% in MM). Univariate analysis identified ferritin and CAR-HEMATOTOX score correlated with t-NM. Multivariate logistic regression showed advanced age (HR 5.03; 95%CI 1.59-18.7, P= 0.009), hemoglobin ≤ 10 g/dl (HR 3.63, 95%CI 1.04-13.30, P = 0.04), and thrombocytopenia (HR 4.06, 95%CI 1.32-14.2, P 0.02) are significantly associated with development of post-CART t-MN. Conclusions: Advanced age, anemia and thrombocytopenia at the time of evaluation for CAR-T eligibility, prior to leukapheresis, are associated with the development of post-treatment severe cytopenia and t-MN. Larger, multi-center studies are needed to validate these findings.

This cohort study examines the role of comprehensive bridging radiotherapy in the setting of chimeric antigen receptor T-cell therapy for non-Hodgkin lymphoma.

Abstract Axicabtagene ciloleucel (axi-cel) is an autologous anti-CD19 chimeric antigen receptor (CAR) T-cell therapy approved for relapsed/refractory (R/R) large B-cell lymphoma (LBCL). Despite extensive data supporting its use, outcomes stratified by race and ethnicity groups are limited. Here, we report clinical outcomes with axi-cel in patients with R/R LBCL by race and ethnicity in both real-world and clinical trial settings. In the real-world setting, 1290 patients who received axi-cel between 2017 and 2020 were identified from the Center for International Blood and Marrow Transplant Research database; 106 and 169 patients were included from the ZUMA-1 and ZUMA-7 trials, respectively. Overall survival was consistent across race/ethnicity groups. However, non-Hispanic (NH) Black patients had lower overall response rate (OR, 0.37; 95% CI, 0.22-0.63) and lower complete response rate (OR, 0.57; 95% CI, 0.33-0.97) than NH White patients. NH Black patients also had a shorter progression-free survival vs NH White (HR, 1.41; 95% CI, 1.04-1.90) and NH Asian patients (HR, 1.67; 95% CI, 1.08-2.59). NH Asian patients had a longer duration of response than NH White (HR, 0.56; 95% CI, 0.33-0.94) and Hispanic patients (HR, 0.54; 95% CI, 0.30-0.97). There was no difference in cytokine release syndrome by race/ethnicity; however, higher rates of any-grade immune effector cell–associated neurotoxicity syndrome were observed in NH White patients than in other patients. These results provide important context when treating patients with R/R LBCL with CAR T-cell therapy across different racial and ethnic groups. ZUMA-1 and ZUMA-7 (ClinicalTrials.gov identifiers: #NCT02348216 and #NCT03391466, respectively) are registered on ClinicalTrials.gov.