Cristina Castilla-Llorente

Phase II clinical trial for the evaluation of bortezomib within the reduced intensity conditioning regimen (RIC) and post‐allogeneic transplantation for high‐risk myeloma patients

The current study was designed to assess the safety and efficacy of bortezomib in combination with fludarabine and melphalan as reduced intensity conditioning before allogeneic stem cell transplantation in patients with high risk multiple myeloma. Sixteen patients were evaluable. The median number of previous line of treatment was 3; all patients had relapsed following a prior autograft and 13 had previously received bortezomib. Fifteen of them either remained stable or improved disease status at day +100 post‐transplant, including 11 patients with active disease. More specifically, nine patients (56%) and five patients (31%) reached complete remission and partial response, respectively. 25% developed grade III acute graft‐versus‐host disease. The cumulative incidence of non‐relapse mortality, relapse and overall survival were 25%, 54% and 41%, respectively, at 3 years. Regarding the non‐haematological toxicity (grade>2), two patients developed peripheral neuropathy, two patients liver toxicity and 1 pulmonary toxicity early post‐transplant. The haematological toxicity was only observed during the first three cycles mostly related to low haemoglobin and platelet levels. The current trial is the first one evaluating the safety and efficacy of bortezomib as part of a reduced intensity conditioning regimen among patients with high risk multiple myeloma.

A novel monoclonal antibody specific for canine CD25 (P4A10): selection and evaluation of canine Tregs.

A monoclonal antibody (mAb), P4A10, was made to the canine interleukin-2 receptor alpha chain (IL-2Ralpha; p55; Tac antigen; CD25) to facilitate studies of canine regulatory T-cells (Treg). By non-reduced Western blot, P4A10 bound to a 55kDa protein, the size of human IL-2Ralpha. In flow cytometry assays, it reacted with a minor population of circulating dog CD3(+)CD4(+) T-cells and the majority (>60%) of in vitro PMA-Ionomycin (PMA-IO)-activated canine CD3(+) T-cells. P4A10 recognized a hematopoietic cell population enriched for FoxP3+ cells as measured by flow cytometry. The P4A10-selected fractions of T-cells had significantly increased copy numbers of CD25, FoxP3, IL-10, and TGFbeta as detected by RT-PCR (reverse transcriptase-PCR) compared to the negative fractions. The P4A10-selected cells inhibited (3)H (tritiated) thymidine incorporation in a mixed leukocyte reaction (MLR) containing responders of the same origin. P4A10-selected T-cells from fresh peripheral blood mononuclear cells had less FoxP3 (p=0.07) by qRT-PCR (quantitative RT-PCR) and were less suppressive (p=0.01) than in vitro alloantigen-activated Treg. The mAb P4A10 is specific for canine CD25 and can be used to facilitate studies of CD25+FoxP3+ Treg in this clinically relevant large animal model.

Immunomodulatory effects of mixed hematopoietic chimerism: immune tolerance in canine model of lung transplantation.

Long‐term survival after lung transplantation is limited by acute and chronic graft rejection. Induction of immune tolerance by first establishing mixed hematopoietic chimerism (MC) is a promising strategy to improve outcomes. In a preclinical canine model, stable MC was established in recipients after reduced‐intensity conditioning and hematopoietic cell transplantation from a DLA‐identical donor. Delayed lung transplantation was performed from the stem cell donor without pharmacological immunosuppression. Lung graft survival without loss of function was prolonged in chimeric (n = 5) vs. nonchimeric (n = 7) recipients (p ≤ 0.05, Fishers test). There were histological changes consistent with low‐grade rejection in 3/5 of the lung grafts in chimeric recipients at ≥1 year. Chimeric recipients after lung transplantation had a normal immune response to a T‐dependent antigen. Compared to normal dogs, there were significant increases of CD4+INFγ+, CD4+IL‐4+ and CD8+ INFγ+ T‐cell subsets in the blood (p < 0.0001 for each of the three T‐cell subsets). Markers for regulatory T‐cell subsets including foxP3, IL10 and TGFβ were also increased in CD3+ T cells from the blood and peripheral tissues of chimeric recipients after lung transplantation. Establishing MC is immunomodulatory and observed changes were consistent with activation of both the effector and regulatory immune response.

Persistent cytotoxic T lymphocyte expansions after allogeneic haematopoietic stem cell transplantation: kinetics, clinical impact and absence of STAT3 mutations.

Peripheral expansion of cytotoxic T lymphocytes (CTL) derived from the graft in the initial stages of allogeneic haematopoietic stem cell transplantation (alloHSCT) immune recovery is a well‐known physiological event. The description of symptomatic large granular lymphocyte leukaemia in this setting may generate uncertainty, mostly in those cases in which the CTL expansion (CTLe) persists beyond the early transplantation period. We aimed to assess the nature of CTLe during the post‐alloHSCT period in 154 adult patients with a long‐term surveillance. We studied the longitudinal kinetics of those expansions, their relationship to clinical events, and their phenotypic and molecular features, including recently reported CTL leukaemia‐STAT3 mutations. Persistent relative CTLe cases are frequent (49%), related with thymoglobulin prophylaxis (P ≤ 0·001), acute graft‐versus‐host disease (GVHD, P = 0·02), and reduced intensity conditioning (P = 0·04). Absolute CTLe are scarce (9%) and related to chronic GVHD. T cell receptor rearrangement was reported as clonal and oligoclonal in the majority of patients with CTLe. The absence of STAT3 mutations and the CD8/CD4 declining longitudinal kinetics in the late period supports its benign nature, expressed clinically by the null detrimental impact of these expansions on post‐transplant outcome and/or serious infectious events.

A retrospective, matched paired analysis comparing bendamustine containing BeEAM versus BEAM conditioning regimen: results from a single center experience

Abstract The combination of carmustine, etoposide, aracytin, and melphalan(BEAM) conditioning regimen in autologous stem-cell transplantation (ASCT) is widely used in patients with relapsed/refractory non-Hodgkin lymphoma (NHL) and Hodgkin lymphoma. It is also an option in patients with very-high risk aggressive NHL in first complete remission (CR). Recently, a phase Ib–II feasibility study using bendamustine replacing carmustine (BCNU) was reported. We report herein a safety and efficacy analysis of bendamustine-EAM (BeEAM) with a control BEAM counterpart paired cohort (1/2). One hundred and two patients were analyzed. Overall survival (OS) and progression-free survival (PFS) were not reached and seemed to be comparable between both groups. However, grade III or greater diarrhea was significantly higher in BeEAM patients (44 vs. 15%, p = .002). The median number of days with fever >38 °C was significantly higher in BeEAM group (5.5 vs. 2, p < .001). This case-control study suggests that BeEAM followed by ASCT using bendamustine at 100 mg/m2/d is effective but has a different toxicity profile than the BEAM regimen.