Bendamustine is safe and effective for lymphodepletion before tisagenlecleucel in patients with refractory or relapsed large B-cell lymphomas.

BACKGROUND: Anti-CD19 chimeric antigen receptor T-cell immunotherapy (CAR-T) is now a standard treatment of relapsed or refractory B-cell non-Hodgkin lymphomas; however, a significant portion of patients do not respond to CAR-T and/or experience toxicities. Lymphodepleting chemotherapy is a critical component of CAR-T that enhances CAR-T-cell engraftment, expansion, cytotoxicity, and persistence. We hypothesized that the lymphodepletion regimen might affect the safety and efficacy of CAR-T. PATIENTS AND METHODS: We compared the safety and efficacy of lymphodepletion using either fludarabine/cyclophosphamide (n = 42) or bendamustine (n = 90) before tisagenlecleucel in two cohorts of patients with relapsed or refractory large B-cell lymphomas treated consecutively at three academic institutions in the United States (University of Pennsylvania, n = 90; Oregon Health & Science University, n = 35) and Europe (University of Vienna, n = 7). Response was assessed using the Lugano 2014 criteria and toxicities were assessed by the Common Terminology Criteria for Adverse Events (CTCAE) version 5.0 and, when possible, the American Society for Transplantation and Cellular Therapy (ASTCT) consensus grading. RESULTS: Fludarabine/cyclophosphamide led to more profound lymphocytopenia after tisagenlecleucel infusion compared with bendamustine, although the efficacy of tisagenlecleucel was similar between the two groups. We observed significant differences, however, in the frequency and severity of adverse events. In particular, patients treated with bendamustine had lower rates of cytokine release syndrome and neurotoxicity. In addition, higher rates of hematological toxicities were observed in patients receiving fludarabine/cyclophosphamide. Bendamustine-treated patients had higher nadir neutrophil counts, hemoglobin levels, and platelet counts, as well as a shorter time to blood count recovery, and received fewer platelet and red cell transfusions. Fewer episodes of infection, neutropenic fever, and post-infusion hospitalization were observed in the bendamustine cohort compared with patients receiving fludarabine/cyclophosphamide. CONCLUSIONS: Bendamustine for lymphodepletion before tisagenlecleucel has efficacy similar to fludarabine/cyclophosphamide with reduced toxicities, including cytokine release syndrome, neurotoxicity, infectious and hematological toxicities, as well as reduced hospital utilization.

CD33-specific chimeric antigen receptor T cells exhibit potent preclinical activity against human acute myeloid leukemia.

Patients with chemo-refractory acute myeloid leukemia (AML) have a dismal prognosis. Chimeric antigen receptor T (CART) cell therapy has produced exciting results in CD19+ malignancies and may overcome many of the limitations of conventional leukemia therapies. We developed CART cells to target CD33 (CART33) using the anti-CD33 single chain variable fragment used in gemtuzumab ozogamicin (clone My96) and tested the activity and toxicity of these cells. CART33 exhibited significant effector functions in vitro and resulted in eradication of leukemia and prolonged survival in AML xenografts. CART33 also resulted in human lineage cytopenias and reduction of myeloid progenitors in xenograft models of hematopoietic toxicity, suggesting that permanently expressed CD33-specific CART cells would have unacceptable toxicity. To enhance the viability of CART33 as an option for AML, we designed a transiently expressed mRNA anti-CD33 CAR. Gene transfer was carried out by electroporation into T cells and resulted in high-level expression with potent but self-limited activity against AML. Thus our preclinical studies show potent activity of CART33 and indicate that transient expression of anti-CD33 CAR by RNA modification could be used in patients to avoid long-term myelosuppression. CART33 therapy could be used alone or as part of a preparative regimen prior to allogeneic transplantation in refractory AML.

Bone marrow-derived cell mobilization by G-CSF to enhance osseointegration of bone substitute in high tibial osteotomy.

PURPOSE: To evaluate granulocyte colony-stimulating factor (G-CSF) efficacy in accelerating bone regeneration following opening-wedge high tibial valgus osteotomy for genu varum. METHODS: A phase II trial was conducted for evaluating the preoperative administration of G-CSF given at 10 µg/kg/day for 3 consecutive days with an additional half-dose 4 h before the opening-wedge high tibial valgus osteotomy. Overall, 12 patients (Group A) received G-CSF treatment, and the subsequent 12 patients (Group B) underwent surgery without G-CSF. The osteotomy gap was filled by a bone graft substitute. Bone marrow cell (BMC) mobilization was monitored by CD34+ve cell and clonogenic progenitor cell analysis. All patients underwent a clinical (Lysholm Knee Scale and SF-36) and radiographic evaluation preoperatively, as well as at given intervals postsurgery. RESULTS: All patients completed the treatment program without major side effects; G-CSF was well tolerated. BMC mobilization occurred in all Group A patients, with median peak values of circulating CD34+ve cells of 110/µL (range 29-256). Circulating clonogenic progenitors paralleled CD34+ve cell levels. A significant improvement in Lysholm Knee Scale was recorded at follow-up in Group A compared to Group B. At the radiographic evaluation, there was a significant increase in osseointegration at the bone-graft junction in Group A at 1, 2, 3 and 6 months postsurgery compared to Group B. The computerized tomography scan of the grafted area at 2 months postsurgery showed no significant difference in the quality of the newly formed bone between the two Groups. CONCLUSIONS: Although the limited number of patients does not allow firm conclusions, the study suggests that G-CSF can be safely administered preoperatively in subjects undergoing opening-wedge high tibial valgus osteotomy; in addition, the clinical, radiographic and CT monitoring indicate that G-CSF and/or mobilized BMCs may hasten bone graft substitute osseointegration. LEVEL OF EVIDENCE: I.

Lymphocyte transformation and autoimmune disorders.

The many features that link autoimmune disorders (AD) and lymphoma are reviewed herein. Firstly, the epidemiology indicates the increased risk of non-Hodgkin's lymphoma (NHL) development in many AD, and especially in Sjögren's syndrome, rheumatoid arthritis and systemic lupus erythematosus. In these AD, the relative risk of NHL occurrence varies between 2 and 4 up to 40 fold higher than in the general population, according to various surveys. Factors favouring or predicting NHL have been reported in detail. B-cell activation and proliferation are part of AD and are essential factors for the onset of malignant cell clones in a deregulated immunological environment. Targeting deregulated or malignant B-cells is the goal of some newly developed treatments. The prototype is anti-CD20 rituximab that has substantially modified the prognosis of B-cell NHL and is also an effective new treatment opportunity for some AD. Similarly, intensified treatments with autologous haematopoietic stem cell transplant (ASCT) that were developed for high-risk lymphoma are now under advanced investigation for use in some refractory AD. Thus, the successful use of rituximab and ASCT in both AD and NHL further emphasizes the close link between these two entities. This review provides details on the main epidemiological features regarding NHL incidence in AD, the pathogenetic factors that favour lymphoma onset and some recent advances in therapeutic approaches that are effective in both autoimmune and malignant lymphoproliferative disorders.

Comparative assessment of telomere length before and after hematopoietic SCT: role of grafted cells in determining post-transplant telomere status.

Our objective was to characterize the role of grafted cells in determining telomere length (TL) after hematopoietic SCT (HSCT). A total of 20 patients undergoing autografts had PBSC collected after two sequential mobilization courses: TL in the first collection was significantly longer than in the second. For their autografts, 10 patients used PBSC from the first collection and 10 from the second. TL was also investigated before and after HSCT and on the graft in 10 allogeneic HSCT. After autografting, patients receiving PBSC from the first collection had BM TL reflecting that of grafted cells (median bp: 7730 on PBSC vs 7610 on post-HSCT BM, P=NS) and significantly longer than TL of the second collection; analogously, patients autografted with PBSC from the second collection had BM TL reflecting that of grafted cells (7360 on PBSC vs 7120 on post-HSCT BM, P=NS) and significantly shorter compared with the first collection. In the allograft setting, eight patients had their pre-transplant TL significantly shorter than donor PBSC (5960 vs 7110; P=0.0005); following HSCT, BM TL (median 7380 bp) was identical to that of the graft (P=NS). We conclude that grafted cells have a major role in determining TL after HSCT.