Recent Bendamustine Treatment Before Apheresis Has a Negative Impact on Outcomes in Patients With Large B-Cell Lymphoma Receiving Chimeric Antigen Receptor T-Cell Therapy.

PURPOSE: Approximately 30%-40% of patients with relapsed/refractory (R/R) large B-cell lymphoma (LBCL) infused with CD19-targeted chimeric antigen receptor (CAR) T cells achieve durable responses. Consensus guidelines suggest avoiding bendamustine before apheresis, but specific data in this setting are lacking. We report distinct outcomes after CAR T-cell therapy according to previous bendamustine exposure. METHODS: The study included CAR T-cell recipients from seven European sites. Safety, efficacy, and CAR T-cell expansion kinetics were analyzed according to preapheresis bendamustine exposure. Additional studies on the impact of the washout period and bendamustine dose were performed. Inverse probability treatment weighting (IPTW) and propensity score matching (PSM) analyses were carried out for all efficacy comparisons between bendamustine-exposed and bendamustine-naïve patients. RESULTS: The study included 439 patients with R/R LBCL infused with CD19-targeted commercial CAR T cells, of whom 80 had received bendamustine before apheresis. Exposed patients had significantly lower CD3+ cells and platelets at apheresis. These patients had a lower overall response rate (ORR, 53% v 72%; P < .01), a shorter progression-free survival (PFS, 3.1 v 6.2 months; P = .04), and overall survival (OS, 10.3 v 23.5 months; P = .01) in comparison with the bendamustine-naïve group. Following adjustment methods for baseline variables, these differences were mitigated. Focusing on the impact of bendamustine washout before apheresis, those with recent (<9 months) exposure (N = 42) displayed a lower ORR (40% v 72%; P < .01), shorter PFS (1.3 v 6.2 months; P < .01), and OS (4.6 v 23.5 months; P < .01) in comparison with bendamustine-naïve patients. These differences remained significant after IPTW and PSM analysis. Conversely, the cumulative dose of bendamustine before apheresis did not affect CAR-T efficacy outcomes. CONCLUSION: Recent bendamustine exposure before apheresis was associated with negative treatment outcomes after CD19-targeted CAR T-cell therapy and should be therefore avoided in CAR T-cell candidates.

Strategy to prevent epitope masking in CAR.CD19+ B-cell leukemia blasts.

Chimeric antigen receptor T-cells (CAR T-cells) for the treatment of relapsing/refractory B-cell precursor acute lymphoblastic leukemia have led to exciting clinical results. However, CAR T-cell approaches revealed a potential risk of CD19-/CAR+ leukemic relapse due to inadvertent transduction of leukemia cells. BACKGROUND: METHODS: We evaluated the impact of a high percentage of leukemia blast contamination in patient-derived starting material (SM) on CAR T-cell drug product (DP) manufacturing. In vitro as well as in vivo models were employed to identify characteristics of the construct associated with better profile of safety in case of inadvertent B-cell leukemia transduction during CAR T-cell manufacturing. RESULTS: The presence of large amounts of CD19+ cells in SM did not affect the transduction level of DPs, as well as the CAR T-cell rate of expansion at the end of standard production of 14 days. DPs were deeply characterized by flow cytometry and molecular biology for Ig-rearrangements, showing that the level of B-cell contamination in DPs did not correlate with the percentage of CD19+ cells in SM, in the studied patient cohort. Moreover, we investigated whether CAR design may affect the control of CAR+ leukemia cells. We provided evidences that CAR.CD19 short linker (SL) prevents complete epitope masking in CD19+CAR+ leukemia cells and we demonstrated in vitro and in vivo that CD19 +CAR(SL)+leukemic cells are killed by CAR.CD19 T-cells. CONCLUSIONS: Taken together, these data suggest that a VL-VH SL may result in a safe CAR-T product, even when manufacturing starts from biological materials characterized by heavy contamination of leukemia blasts.

Blastic plasmacytoid dendritic cell neoplasm frequently shows occult central nervous system involvement at diagnosis and benefits from intrathecal therapy.

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare aggressive myeloid neoplasm which shows a high rate of central nervous system (CNS) recurrence and overall survival (OS) of <1 year. Despite this, screening for CNS involvement is not routinely performed at diagnosis and intrathecal (IT) prophylaxis is not regularly administered in BPDCN. Here, we prospectively evaluated 13 consecutive BPDCN patients for the presence of CNS involvement by flow cytometry. Despite none of the patients presented with neurological symptoms, occult CNS involvement was detected in 6/10 cases evaluated at diagnosis and 3/3 studied at relapse/progression. BPDCN patients evaluated at diagnosis received IT treatment -either CNS prophylaxis (n = 4) or active therapy (n = 6)- and all but one remain alive (median follow-up of 20 months). In contrast, all three patients assessed at relapse/progression died. The potential benefit of IT treatment administered early at diagnosis on OS and CNS recurrence-free survival of BPDCN was further confirmed in a retrospective cohort of another 23 BPDCN patients. Our results show that BPDCN patients studied at diagnosis frequently display occult CNS involvement; moreover, they also indicate that treatment of occult CNS disease might lead to a dramatically improved outcome of BPDCN.

Classification and clinical behavior of blastic plasmacytoid dendritic cell neoplasms according to their maturation-associated immunophenotypic profile.

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare subtype of leukemia/lymphoma, whose diagnosis can be difficult to achieve due to its clinical and biological heterogeneity, as well as its overlapping features with other hematologic malignancies. In this study we investigated whether the association between the maturational stage of tumor cells and the clinico-biological and prognostic features of the disease, based on the analysis of 46 BPDCN cases classified into three maturation-associated subgroups on immunophenotypic grounds. Our results show that blasts from cases with an immature plasmacytoid dendritic cell (pDC) phenotype exhibit an uncommon CD56- phenotype, coexisting with CD34+ non-pDC tumor cells, typically in the absence of extramedullary (e.g. skin) disease at presentation. Conversely, patients with a more mature blast cell phenotype more frequently displayed skin/extramedullary involvement and spread into secondary lymphoid tissues. Despite the dismal outcome, acute lymphoblastic leukemia-type therapy (with central nervous system prophylaxis) and/or allogeneic stem cell transplantation appeared to be the only effective therapies. Overall, our findings indicate that the maturational profile of pDC blasts in BPDCN is highly heterogeneous and translates into a wide clinical spectrum -from acute leukemia to mature lymphoma-like behavior-, which may also lead to variable diagnosis and treatment.

Detection and outcome of occult leptomeningeal disease in diffuse large B-cell lymphoma and Burkitt lymphoma.

The benefit of intrathecal therapy and systemic rituximab on the outcome of diffuse large B-cell lymphoma at risk of central nervous system disease is controversial. Furthermore, the effect of intrathecal treatment and rituximab in diffuse large B-cell and Burkitt lymphoma with occult leptomeningeal disease detected by flow cytometry at diagnosis is unknown. Untreated diffuse large B-cell (n=246) and Burkitt (n=80) lymphoma at clinical risk of central nervous system disease and having had pre-treatment cerebrospinal fluid were analyzed by flow cytometry and cytology. Spinal fluid involvement was detected by flow cytometry alone (occult) in 33 (13%) diffuse large B-cell and 9 (11%) Burkitt lymphoma patients, and detected by cytology in 11 (4.5%) and 5 (6%) patients, respectively. Diffuse large B-cell lymphoma with occult spinal fluid involvement had poorer survival (P=0.0001) and freedom from central nervous system relapse (P<0.0001) compared to negative cases. Burkitt lymphoma with occult spinal fluid involvement had an inferior freedom from central nervous system relapse (P=0.026) but not survival. The amount of intrathecal chemotherapy was quantitatively associated with survival in diffuse large B-cell lymphoma with (P=0.02) and without (P=0.001) occult spinal fluid involvement. However, progression of systemic disease and not control of central nervous system disease was the principal cause of treatment failure. In diffuse large B-cell lymphoma, systemic rituximab was associated with improved freedom from central nervous system relapse (P=0.003) but not with survival. Our results suggest that patients at risk of central nervous system disease should be evaluated by flow cytometry and that intrathecal prophylaxis/therapy is beneficial.

Contribution of cerebrospinal fluid sCD19 levels to the detection of CNS lymphoma and its impact on disease outcome.

Flow cytometry (FCM) is more sensitive than conventional cytology for detection of occult leptomeningeal lymphoma; however, some FCM-negative patients show central nervous system (CNS) recurrence. Here, we evaluated the cerebrospinal fluid (CSF) levels of 13 B-cell-associated markers and their contribution to the diagnosis of CNS lymphoma in 91 diffuse large B-cell lymphomas (DLBCL) and 22 Burkitt lymphomas (BLs). From all markers tested, CD19 was the most informative. Thus, higher soluble CD19 (sCD19) levels were associated with a greater frequency of neurological symptoms in DLBCL and BL and with parenchymal CNS lymphoma in DLBCL; sCD19 emerged as a powerful predictor of event-free and overall survival in DLBCL and BL, particularly when combined with FCM detection of CNS disease. These results support the utility of combined FCM detection of lymphoma cells and assessment of sCD19 levels in CSF, for more accurate identification of CNS disease in DLBCL and BL patients.

Enhanced immunological response by dendritic cells in male hypogonadism.

BACKGROUND: The effect of male hypogonadism on the immune response is poorly understood, even though testosterone has both immunosuppressive and anti-inflammatory effects in men. DESIGN: In this study, we compared the distribution and functional status of peripheral blood (PB) monocytes, dendritic cells (DCs) [CD16(+) (monocytoid), CD33(+) (myeloid) and CD33(-) (plasmacytoid)] and CD4(+) CD25(+)CD127(-/lo) regulatory T cells from hypogonadic men and control subjects. Immunophenotypic studies were performed both on resting and in vitro-stimulated cells. RESULTS: Overall, no significant differences were detected on the number of monocytes, DCs and CD4(+) CD25(+) CD127(-/lo) regulatory T cells between both groups of subjects. However, hypogonadic men showed slightly higher numbers of circulating CD16(+) cells expressing the CD107b activation/degranulation-associated marker than controls, such differences reaching statistical significance after in vitro stimulation with CpG oligodeoxynucleotides. Interestingly, antigen-stimulated expression of CD107b on CD16(+) cells inversely correlated with the serum concentrations of total testosterone (r(2)=-0.45; P=0.01), free testosterone (r(2)=-0.48; P=0.005), calculated free testosterone (r(2)=-0.44; P=0.01) and bioavailable testosterone (r(2)=-0.46; P=0.008) among all cases studied, as well as with both the LH (r(2)=-0.53, P=0.04) and FSH (r(2)=-0.54, P=0.04) serum levels among hypogonadic men. CONCLUSIONS: These findings show an enhanced immunological response of circulating (activated) CD16(+) DCs to antigen stimulation, which was inversely related to testosterone and gonadotropin serum levels. Such findings suggest a modulation by the hypothalamic-hypophyseal-gonadal axis of the immune response and may have clinical implications for hypogonadic men, as regards susceptibility to autoimmune diseases and increased responses to antigenic stimuli.

Immunophenotypical, morphologic, and functional characterization of maturation-associated plasmacytoid dendritic cell subsets in normal adult human bone marrow.

BACKGROUND: Information about maturation of plasmacytoid dendritic cell precursors (pre-pDCs) in normal bone marrow (BM) remains limited. STUDY DESIGN AND METHODS: Immunophenotypical, morphologic, and functional changes associated with maturation of pre-pDCs were analyzed in adult normal human BM (n = 45). RESULTS: Three pre-pDC maturation stages, with an increasingly higher degree of maturity, were systematically identified: CD34++/HLA-DR++/+++/CD123++/CD45+/++ (Stage I), CD34+/HLA-DR+/++/CD123++/+++/CD45+/++ (Stage II), and CD34-/HLA-DR++/CD123++/+++/CD45++ (Stage III) cells. Lymphoid- and early myeloid-associated molecules, as well as CD86, were coexpressed in Stage I pre-pDCs, being down regulated afterward. CD304 and CD85j appeared in Stage I, progressively increasing their levels thereafter. Interestingly, cutaneous lymphocyte-associated antigen was heterogeneously expressed throughout the maturation, particularly in Stage I pre-pDCs. The morphologic appearance of Stage I pre-pDCs was consistent with their undifferentiated stage, while Stage II/III cells showed morphologic features of more differentiated cells. From the functional point of view, only Stage II and Stage III pre-pDCs were capable of inducing allogeneic T-cell proliferation, the later subset also showing interferon-g secretion; in contrast, Stage I pre-pDCs showed the highest endocytic ability. CONCLUSION: In summary, three maturation stages of pre-pDCs can be identified in adult normal BM, which show unique phenotypical, morphologic, and functional characteristics; these results provide a frame of reference for a better understanding of pDC malignancies.