A Phase 2 Trial of Fludarabine Combined With Subcutaneous Alemtuzumab for the Treatment of Relapsed/Refractory B-Cell Chronic Lymphocytic Leukemia.

BACKGROUND: Alemtuzumab is effective in fludarabine-refractory patients with chronic lymphocytic leukemia. We performed a phase 2 study of alemtuzumab in combination with fludarabine in patients with relapsed disease. PATIENTS AND METHODS: Patients received alemtuzumab and fludarabine daily on days 1 to 5 of a 28-day cycle for up to 6 cycles with the primary objective of determining the rate of complete response. Of 60 enrolled patients, 51 had previously received fludarabine, and 60% had received 3 or more prior therapies. RESULTS: Five patients experienced complete response (8.3%) and 12 experienced partial response, yielding an overall response rate of 28.3% for the intention-to-treat population. Among the 41 patients who completed at least 4 cycles of therapy, the complete response rate was 20%. Median progression-free survival was 211 days. Forty-seven percent of patients experienced cytomegalovirus viremia, including 4 patients with symptomatic cytomegalovirus disease. All patients responded to antiviral therapy. CONCLUSION: Despite some evidence of efficacy in this setting, the primary end point for the study was not met. In the era of targeted agents that are well tolerated, the combination of fludarabine and alemtuzumab should be used rarely for a select group of fit patients who are refractory to standard therapies.

Evaluation of peripheral blood stem cell quality in products transported by traditional courier or commercial overnight shipping services.

BACKGROUND: Peripheral blood stem cell (PBSC) products have traditionally been transported from the collection center to a transplant center using validated volunteer courier-based procedures. Evolving airline service strategies and security policies have complicated this model of product transport. This study was designed to evaluate the feasibility of transporting PBSC products using commercial overnight shipping services, while maintaining product quality, compared to courier-transported products. STUDY DESIGN AND METHODS: Five PBSC products were collected from healthy volunteer donors and divided to evaluate product quality when transported either by volunteer courier or by commercial overnight shipping service. Products were evaluated on the day of collection and at 24, 48, and 72 hours postcollection for total nucleated cell (TNC) count, cell viability, progenitor cell numbers, and progenitor cell lineage growth potential (colony-forming units [CFUs]) to assess product composition and quality associated with each cohort. RESULTS: No delivery delays were encountered and all products were received intact. Measurements of product composition and quality demonstrated no differences in TNC count (p=0.893), cell viability (p=0.409), CD34+ progenitor cell content (p=0.509), or CFU-granulocyte-macrophage growth potential (p=0.827). CONCLUSIONS: We found no difference in product viability, progenitor cell content, or product potency in PBSC products transported either by volunteer courier or by commercial overnight shipping.

VIPhyb, an antagonist of vasoactive intestinal peptide receptor, enhances cellular antiviral immunity in murine cytomegalovirus infected mice.

Vasoactive intestinal peptide (VIP) is a neuropeptide hormone that suppresses Th1-mediated cellular immunity. We previously reported that VIP-knockout (VIP-KO) mice have enhanced cellular immune responses and increased survival following murine cytomegalovirus (mCMV) infection in C57BL/6 mice. In this study, we tested whether treatment with a VIP receptor antagonistic peptide protects C57BL/6 and BALB/c mice from mCMV-infection. One week of daily subcutaneous injections of VIPhyb was non-toxic and did not alter frequencies of immune cell subsets in non-infected mice. VIPhyb administration to mCMV-infected C57BL/6 and BALB/c mice markedly enhanced survival, viral clearance, and reduced liver and lung pathology compared with saline-treated controls. The numbers of effector/memory CD8+ T-cells and mature NK cells were increased in VIPhyb-treated mice compared with PBS-treated groups. Pharmacological blockade of VIP-receptor binding or genetic blockade of VIP-signaling prevented the up-regulation of PD-L1 and PD-1 expression on DC and activated CD8+ T-cells, respectively, in mCMV-infected mice, and enhanced CD80, CD86, and MHC-II expression on conventional and plasmacytoid DC. VIPhyb-treatment increased type-I IFN synthesis, numbers of IFN-γ- and TNF-α-expressing NK cells and T-cells, and the numbers of mCMV-M45 epitope-peptide-MHC-I tetramer CD8+ T-cells following mCMV infection. VIP-treatment lowered the percentage of Treg cells in spleens compared with PBS-treated WT mice following mCMV infection, while significantly decreasing levels of serum VEGF induced by mCMV-infection. The mice in all treated groups exhibited similar levels of anti-mCMV antibody titers. Short-term administration of a VIP-receptor antagonist represents a novel approach to enhance innate and adaptive cellular immunity in a murine model of CMV infection.

A randomized trial comparing the combination of granulocyte-macrophage colony-stimulating factor plus granulocyte colony-stimulating factor versus granulocyte colony-stimulating factor for mobilization of dendritic cell subsets in hematopoietic progenitor cell products.

The ability of granulocyte colony-stimulating factor (G-CSF) and granulocyte-macrophage colony-stimulating factor (GM-CSF) administration to increase the content of blood leucocytes and hematopoietic progenitor cells (HPCs) is well established, yet the effect of these cytokines on immune function is less well described. Recent data indicate that plasmacytoid dendritic cells (DC2) may inhibit cellular immune response. We hypothesized that administration of the combination of G-CSF and GM-CSF after chemotherapy would reduce the type 2, or plasmacytoid, DC2 content of the autologous blood HPC grafts compared with treatment with G-CSF alone. To test this hypothesis, 35 patients with lymphoma and myeloma were randomized to receive either G-CSF or the combination of G-CSF plus GM-CSF after chemotherapy, and blood HPC grafts were collected by apheresis. Cytokine-related adverse events between the 2 groups were similar. More than 2 x 10(6)CD34 + cells per kilogram were collected by apheresis in 14 of 18 subjects treated with G-CSF and in 16 of 17 subjects treated with GM-CSF plus G-CSF ( p = not significant). There were minor differences between the 2 groups with respect to the content of T cells and CD34 + cells in the apheresis products. However, grafts collected from recipients of the combination of GM-CSF plus G-CSF had significantly fewer DC2 cells and similar numbers of DC1 cells compared with recipients treated with G-CSF alone. A third cohort of patients received chemotherapy followed by the sequential administration of G-CSF and the addition of GM-CSF 6 days later. Grafts from these patients had a markedly reduced DC2 content compared with those from patients treated either with G-CSF alone or with the concomitant administration of both cytokines. These data, and recent data that cross-presentation of antigen by DC2 cells may induce antigen-specific tolerance among T cells, suggest that GM-CSF during mobilization of blood HPC grafts may be a clinically applicable strategy to enhance innate and acquired immunity after autologous and allogeneic HPC transplantation.

Facilitating T-cell immune reconstitution after haploidentical transplantation in adults.

Delayed reconstitution of cellular immunity following T-cell-depleted, CD34-enriched, allogeneic hematopoietic progenitor cell transplantation (HPCT) is the major cause of morbidity and mortality following haploidentical transplantation in adults. This is illustrated in our recent study of 28 high-risk adult patients (median age 31) who were treated with conditioning regimens containing antithymocyte globulin (ATG) before T-cell-depleted, CD34-enriched allogeneic HPCT. Overall mortality was 93% (26/28 patients) with a median survival of 4 months posttransplant. Poor cellular immune reconstitution contributed to death of 21/28 patients, with eight deaths due to opportunistic infections and seven deaths due to relapse. While recovery of normal numbers of circulating NK cells and B-cells occurred within the first 1-2 months posttransplant, recovery of normal numbers of blood T-cells was suppressed for more than 1 year. The mean half-life of active ATG levels in serum was 6 days; rapid clearance suggested that residual ATG did not contribute to the delay of posttransplant T-cell reconstitution. Rapid T-cell reconstitution was seen only in younger patients, indicating that poor thymic function and the absence of T-cells in the graft are the major causes of delayed recovery of cellular immunity. Improved cellular immunity after T-cell-depleted haploidentical HPCT will thus require novel strategies to adoptively transfer antigen specific donor T-cells without inducing lethal graft-versus-host disease (GvHD). This problem has been addressed in a preclinical murine model of MHC-mismatched bone marrow transplantation. Donor T-cells treated ex vivo with fludarabine or a UVA light-activated psoralen compound (amotosalen) have a markedly reduced ability to induce GvHD, yet the treated T-cells confer protection against murine cytomegalovirus and an infused leukemic cell line. Polyclonal donor T-cells reconstituted the blood and lymphoid compartments posttransplant and expanded in vivo. Derivatives of ex-vivo-treated donor T-cells retained the ability to produce cytokines and proliferate in response to antigen challenge. The mechanism of reduced GvHD potential of ex-vivo-treated T-cells appears to be selection of a subset of memory donor T-cells that do not initially home to secondary lymphoid organs and have reduced capacity for producing inflammation in the immediate posttransplant period. Direct selection of the memory subset by high-speed FACS confirmed the improved therapeutic index in the murine model system. Preclinical data indicate the feasibility of treating human T-cells with fludarabine, psoralen, or direct selection based upon the memory phenotype to efficiently produce a population of polyclonal donor T-cells with reduced GvHD activity. A planned clinical phase 1 trial of adoptive therapy utilizing ex vivo psoralen-treated donor T-cells in recipients of T-cell-depleted haploidentical HPCT is presented.

Pharmacokinetics and pharmacodynamics of anti-thymocyte globulin in recipients of partially HLA-matched blood hematopoietic progenitor cell transplantation.

Polyclonal anti-thymocyte globulin (ATG) administered before allogeneic blood hematopoietic progenitor cell transplantation reduces the risks of graft rejection and graft-versus-host disease, but may delay posttransplant immune reconstitution caused by delayed clearance of ATG from the blood. We studied graft-versus-host disease, infections, and the kinetics of immune reconstitution in 28 patients with very poor-risk hematologic malignancies who received lymphocyte-depleted, CD34(+) cell-enriched hematopoietic progenitor cell grafts from partially HLA-matched related donors (PMRD). The incidence of these clinical events was correlated with blood ATG levels in 19 transplant recipients who received rabbit ATG (r-ATG, thymoglobulin) during conditioning. Total r-ATG and the fraction of ATG antibodies that bind human cells (active ATG) were measured for up to 45 days posttransplantation using enzyme-linked immunosorbent assay and flow cytometry assays. Three patients received equine ATG (e-ATG; total dose of 60 mg/kg/day), 3 patients received 10 mg/kg r-ATG, and 22 patients received 6 mg/kg r-ATG during conditioning. All evaluable patients engrafted. Median numbers of blood CD4(+) and CD8(+) T cells at 100 days posttransplantation were 15 and 8 cells/microL, respectively. Acute graft-versus-host disease developed in 3 of 3 recipients of e-ATG and 1 of 25 recipients of r-ATG. Rapid T-cell reconstitution was seen only in younger patients. Overall mortality was 93% (26/28 patients) with poor immune reconstitution contributing to death in 21 of 28 patients. Recipients of 6 mg/kg r-ATG had peak levels of total and active r-ATG of 64+/-20 microg/mL and 9.2+/-5.8 microg/mL, respectively, with clearance of active r-ATG (t(1/2)6 days) to sub-therapeutic levels (<1 microg/mL) by a median of 15 days posttransplantation (range, 8-38 days). Delayed immune reconstitution is likely a consequence of ex vivo and in vivo purging of donor T cells in the graft coupled with inadequate thymic function rather than persistence of active r-ATG in the blood for months posttransplantation.

A randomized, placebo-controlled trial of subcutaneous administration of GM-CSF as a vaccine adjuvant: effect on cellular and humoral immune responses.

Thirty healthy volunteers were randomly assigned to receive either a single subcutaneous injection of GM-CSF or placebo at the time of vaccination with tetanus and diptheria toxoid (Td), influenza and hepatitis A vaccines. Humoral response was measured by weekly serum samples assayed for antibodies to tetanus toxoid (TT), influenza and hepatitis A; while cellular response to TT was determined by measuring IL-2 expression in T-cells following in vitro exposure to TT antigen using a flow cytometric assay. It was hypothesized that (1). GM-CSF would augment immune response and (2). that the frequencies of TT responsive T-cells in the blood would predict humoral responses. The administration of subcutaneous GM-CSF as an adjuvant at the time of vaccination did not augment the antibody responses to influenza or hepatitis A in normal volunteers when compared to placebo. Subjects who received GM-CSF had statistically significant lower increases in anti-tetanus antibodies than placebo recipients. Immunization with TT resulted in an increase in the frequency of antigen responsive T-cells in the blood over time. The frequencies of TT responsive T-cells in baseline blood samples were correlated with baseline anti-tetanus antibody titers, but humoral and cellular responses were not correlated following vaccination. Recipients of GM-CSF did not develop significantly higher numbers of TT responsive T-cells after vaccination compared to recipients who received placebo.

DC2 effect on survival following allogeneic bone marrow transplantation.

The graft-vs-tumor effect is an important part of the curative potential of allogeneic transplantation. We characterized the effect of transplanted donor mononuclear cells on relapse- and event-free survival after allogeneic bone marrow transplantation (BMT). We studied 113 consecutive patients with hematologic malignancies who received non-T-cell-depleted BMT from human leukocyte antigen (HLA)-matched siblings. Most patients (n = 103) received busulfan (Myleran)-based conditioning, and all patients received standard short-course methotrexate and tacrolimus (Prograf) as graft-vs-host disease prophylaxis. Sixty-four patients had low-risk diagnoses (acute lymphoblastic leukemia/acute myeloid leukemia [first complete remission], myelodysplastic syndrome [refractory anemia/refractory anemia with ring sideroblasts], and chronic myeloid leukemia [first chronic phase]); 49 patients had high-risk diagnoses (all others). Cox regression analyses evaluated risk strata, age, gender, and the numbers of nucleated cells, CD3-positive T cells, CD34-positive hematopoietic cells, and type 2 dendritic cells (DC2) as covariates for event-free survival, relapse, and nonrelapse mortality. Recipients of larger numbers of DC2 cells had significantly lower event-free survival, a lower incidence of chronic graft-vs-host disease, and an increased incidence of relapse. Recipients of larger numbers of CD34-positive cells had improved event-free survival; recipients of fewer CD34-positive cells had delayed hematopoietic engraftment and increased death from infections. In conclusion, content of donor DC2 cells was associated with decreased chronic graft-vs-host disease and graft-vs-leukemia effects consistent with Th2/Tc2 polarization of donor Tcells following allogeneic bone marrow transplantation.