Biomedical subjects

L J Burns

Publications and source records attributed to L J Burns.

At least 19 recordsLinked to original sources

PubMed2007

Fludarabine vs cladribine plus busulfan and low-dose TBI as reduced intensity conditioning for allogeneic hematopoietic stem cell transplantation: a prospective randomized trial.

Purine analogs are often used for conditioning preceding allogeneic hematopoietic stem cell transplantation (HCT). We prospectively tested fludarabine (Flu) 40 mg/m(2)/day x 5 days vs cladribine (Clad) 10 mg/m(2)/day x 5 days plus oral busulfan (1 mg/kg q6 h x 2 days) and total body irradiation 200 cGy in 32 recipients of matched sibling and unrelated donor (URD) HCT. Patients were similar in age (median 52 years), diagnosis, extensive pre-HCT therapy (56 vs 63%), and high-risk disease status (81 vs 93%). Neutrophil engraftment was prompt (median 11 vs 12 days), but early graft failure using Clad halted randomization. Platelet recovery was prompt (median Flu 18 vs Clad 24 days). Graft-versus-host disease (GVHD) after Flu vs Clad was similar; (acute grade II/IV 56 vs 69%, P=0.26; chronic 50 vs 31%, P=0.27). Nonrelapse mortality (Flu 25 vs Clad 38%, P=0.47) and progression-free survival at 3 years were similar as well. Multivariate analyses showed slightly, but not significantly lower relative risk (RR) of neutrophil engraftment with Clad (RR 0.6 (95% CI 0.2-1.3) P=0.16) and with URD RR 0.4 (0.2-1.0) P=0.04). Older patients with advanced hematologic malignancies achieve satisfactory outcomes using either of these reduced intensity conditioning regimens.

Adult↗

PubMed2006

Recommended screening and preventive practices for long-term survivors after hematopoietic cell transplantation: joint recommendations of the European Group for Blood and Marrow Transplantation, Center for International Blood and Marrow Transplant Research, and the American Society for Blood and Marrow Transplantation (EBMT/CIBMTR/ASBMT).

More than 40,000 hematopoietic cell transplants (HCTs) are performed worldwide each year. With improvements in transplant technology, larger numbers of transplant recipients survive free of the disease for which they were transplanted. However, there are late complications that can cause substantial morbidity. Many survivors are no longer under the care of transplant centers and many community health-care providers may be unfamiliar with health matters relevant to HCT. The Center for International Blood and Marrow Transplant Research (CIBMTR), European Group for Blood and Marrow Transplantation (EBMT), and American Society for Blood and Marrow Transplantation (ASBMT) have developed these recommendations to offer care providers suggested screening and prevention practices for autologous and allogeneic HCT survivors.

Delivery of Health Care↗

PubMed2005

Results of autologous and allogeneic hematopoietic cell transplant therapy for multiple myeloma.

We compared the results of autologous and allogeneic peripheral blood hematopoietic cell transplant (HCT) in 87 patients with multiple myeloma using myeloablative preparative regimen. Autologous transplant (n=70) led to a lower 100-day transplant-related mortality (TRM) of 4% [0-9%] compared to 18% [0-36%] in allogeneic recipients (P=0.02). More frequent complete responses were seen in allogeneic recipients (64% [37-91%] vs 34% [23-45%] in autologous recipients, P=0.09). In autologous recipients, survival at 1 year was 86% [80-95%] and, it fell to 50% [47-75%] at 4 years, whereas in allogeneic recipients, survival at 1 and 4 years remained at 64% [40-87%]. In patients surviving more than one year, 4-year survival was superior in allogeneic (100%) vs autologous recipients (58% [41-75%], P=0.02). A trend toward higher relapse was seen in autologous transplant patients (73% [55-90%] vs 37% [11-63%] in allogeneic transplant patients, P=0.1). We observed good tolerance of myeloablative conditioning regimen followed by either autologous or allogeneic transplant. Although autologous HCT is associated with lower TRM, allogeneic HCT has acceptable TRM, and is more likely to provide a sustained response. Allogeneic HCT may be suitable in younger patients, soon after diagnosis, and in those with chemosensitive disease.

Adult↗

PubMed2003

Transformed lymphoma: an Achilles' heel of non-Hodgkin's lymphoma.

Transformed lymphoma has a reported incidence of 10-70% among patients with follicular lymphoma. Interpreting the wide-ranging estimates for incidence, survival, and effects of interventions from various studies is complicated by the use of different definitions of lymphoma transformation. Problems in defining histologic transformation will be addressed in this review. To date, there are no reliable markers of risk for transformation or factors predictive of survival. The prognosis for transformed lymphoma is generally poor, with most patients surviving only a few months, though some with limited disease that is chemosensitive may experience prolonged survival. Immunotherapy, particularly monoclonal antibodies and radioimmunoconjugates, holds promise but more experience is necessary. Approximately 200 patients are included in published series of autologous transplantation; of these, one-third remain disease free at 5 years, not dissimilar to reported outcomes for nontransformed disease. However, the treatment-related mortality is higher than in nontransformed disease, and there is a significant incidence of post-transplant myelodysplastic syndrome. The role of allogeneic transplant has yet to be pursued, but should be explored for its potential for a graft-versus-lymphoma effect. Advances in microarray gene analysis and biology may facilitate the understanding of mechanisms of transformation, development of a prognostic index and creation of tailored therapy.

Cell Transformation, Neoplastic↗

PubMed2003

IL-2-based immunotherapy after autologous transplantation for lymphoma and breast cancer induces immune activation and cytokine release: a phase I/II trial.

We determined the safety, immune activating effects, and potential efficacy of i.v. infusion of ex vivo interleukin-2 (IL-2) activated natural killer (NK) cells (part I) or IL-2 boluses (part II) during daily s.c. IL-2 administration following hematopoietic recovery from autologous transplantation. In all, 57 patients with relapsed lymphoma (n=29) or metastatic breast cancer (n=28) were enrolled. In part I of the study, 34 patients were enrolled at three dose levels of ex vivo IL-2-activated NK cells. Lymphaphereses were performed on days 28 and 42 of s.c. IL-2 administration. Following overnight ex vivo IL-2 activation of the pheresis product, the cells were reinfused the following day. In part II, 23 patients were enrolled at three dose levels of supplemental i.v. IL-2 bolus infusions, given on days 28 and 35 during s.c. IL-2 administration. Toxicities were generally mild, and no patient required hospitalization. Lytic function was markedly enhanced for fresh peripheral blood mononuclear cells (PBMNCs) obtained 1 day postinfusion of either IL-2-activated cells or IL-2 boluses. IL-2 boluses transiently increased the levels of IL-6, IFN-gamma, TNF-alpha and IL1-beta, with increases in IL-6 and IFN-gamma being dose dependent. A total of 37 patients (19 patients with lymphoma, 18 with breast cancer) treated with an optimum dose of post-transplant immunotherapy (defined as having received 1.75 x 10(6) IU/m(2)/day of s.c. IL-2 plus at least one of the planned ex vivo IL-2-activated cell infusions/IL-2 boluses) could be matched with controls from the Autologous Blood and Marrow Transplant Registry database. The matched-pairs analysis demonstrated no improvement in disease outcomes of survival and relapse. We conclude that IL-2-activated cells/IL-2 boluses can be safely administered, generate PBMNCs with enhanced cytotoxicity against NK-resistant targets, and increase cytokine levels. With this dose and schedule of administration of IL-2, no improvement in patient disease outcomes was noted. Alternative strategies will be needed to exploit the immunotherapeutic potential of IL-2-activated NK cells.

Adult↗

PubMed2003

Preclinical studies targeting normal and leukemic hematopoietic cells with Yttrium-90-labeled anti-CD45 antibody in vitro and in vivo in nude mice.

A study was undertaken to investigate the suitability of using a high affinity (Kd = 1.1 nM) anti-CD45 monoclonal antibody for delivering the high energy beta-particle emitting isotope (90)Y to lymphohematopoietic target cells in vivo. The antibody, AHN-12, recognized the tyrosine phosphatase CD45 expressed on the surface of normal and malignant hematopoietic cells and studies showed that it reacted with both CD45-expressing normal peripheral blood cells and leukemia cells from patients. The antibody was readily labeled with (90)Y using the highly stable chelate 1B4M-DTPA and the radioimmunoconjugate was designated (90)Y-anti-CD45. The agent selectively bound to CD45(+) B cell line Daudi, but not CD45(-) control cells and significantly (p = 0.007) more bound to Daudi tumors growing in athymic nude mice than did a control non-reactive antibody. Moreover, biodistribution data correlated well to an anti-Daudi effect observed against established tumors in nude mice. The effect was dose dependent and irreversible with the best results in mice receiving a single dose of 137 microCi (90)Y-anti-CD45. These mice displayed a significantly (p < 0.0095) better anti-tumor effect than a control (90)Y-labeled antibody and survived over 135 days with no evidence of tumor. Histology studies showed no significant injury to kidney, liver, or small intestine even at 254 microCi, the highest dose tested. Because radiolabeled anti-CD45 antibody can be used to deliver radiation selectively to lymphohematopoietic tissue, these data indicate that this agent may be used to improve treatment of hematopoietic malignancies, particularly leukemia and lymphoma, when combined with hematopoietic stem cell transplantation in a future clinical trial.

Animals↗

PubMed2002

Randomized clinical trial of ganciclovir vs acyclovir for prevention of cytomegalovirus antigenemia after allogeneic transplantation.

Cytomegalovirus (CMV) disease remains a major cause of morbidity following allogeneic stem cell transplantation (SCT). In a prospective randomized trial, we tested prophylactic therapy with ganciclovir or acyclovir for patients at high risk of disease. Ninety-one CMV seropositive recipients of related (n = 53) and unrelated (n = 38) donor transplants were enrolled. All patients received intravenous (i.v.) ganciclovir 5 mg/kg every 12 h days -7 to -2, followed by acyclovir 10 mg/kg i.v. every 8 h from day -1 until neutrophil engraftment. Patients were then randomly assigned to either ganciclovir (n = 45) or acyclovir (n = 46) until day 100 post transplant. Any degree of antigenemia was treated with ganciclovir 5 mg/kg i.v. twice a day for 2 weeks, followed by 5 mg/kg i.v. each weekday for 6 weeks. At day 100, the cumulative incidence of antigenemia was 31% (95% CI 17-45%) for ganciclovir and 41% (95% CI 26-56%) (P = 0.22) for acyclovir prophylaxis, respectively. The assigned prophylaxis cohort did not predict for CMV antigenemia. The cumulative incidence of CMV disease at 12 months was 13% (95% CI 3-23%) and 17% (95% CI 6-28%) (P = 0.59) for the ganciclovir- and acyclovir-treated groups, respectively. An absolute neutrophil count (ANC) <or=1500 x 10(6)/l at randomization (P < 0.01) and grade II-IV acute graft-versus-host-disease (P = 0.01), but not the assigned prophylaxis cohort (P = 0.62), were independent risk factors for CMV disease. The incidence of fungal infections and renal insufficiency was similar across treatment groups; however, bacterial infections and secondary neutropenia occurred more frequently in the ganciclovir group. With our study powered to detect a 60% reduction in antigenemia with ganciclovir prophylaxis, we did not find a statistically significant difference between ganciclovir and acyclovir when used as part of an overall strategy for prevention of CMV antigenemia and disease in SCT, although fewer side-effects occurred with acyclovir treatment.

Acyclovir↗

PubMed2001

Autotransplants for Hodgkin's disease in first relapse or second remission: a report from the autologous blood and marrow transplant registry (ABMTR).

Although patients with relapsed Hodgkin's disease have a poor prognosis with conventional therapies, high-dose chemotherapy and autologous hematopoietic stem cell transplantation (autotransplantation) may provide long-term progression-free survival. We reviewed data from the Autologous Blood and Marrow Transplant Registry (ABMTR) to determine relapse, disease-free survival, overall survival, and prognostic factors in this group of patients. Detailed records from the ABMTR on 414 patients with Hodgkin's disease in first relapse (n = 295) or second complete remission (CR) (n = 119) receiving an autotransplant from 1989 to 1995 were reviewed. Median age was 29 (range, 7-64) years. Median time from diagnosis to relapse was 18 (range, 6-219) months; median time from relapse to transplant was 5 (range, <1-215) months. Most patients received high-dose chemotherapy without total body irradiation for conditioning (n = 370). The most frequently used high-dose regimen was cyclophosphamide, BCNU, VP-16 (CBV) (n = 240). The graft consisted of bone marrow (n = 246), blood stem cells (n = 112), or both (n = 56). Median follow-up was 46 (range, 5-96) months. One hundred-day mortality (95% confidence interval) was 7 (5-9)%. One hundred and sixty-five of 295 patients (56%) transplanted in relapse achieved CR after autotransplantation. Of these, 61 (37%) recurred. Twenty-four of 119 patients (20%) transplanted in CR recurred. The probability of disease-free survival at 3 years was 46 (40-52)% for transplants in first relapse and 64 (53-72)% for those in second remission (P < 0.001). Overall survival at 3 years was 58 (52-64)% after transplantation in first relapse and 75 (66-83)% after transplantation in second CR (P < 0.001). In multivariate analysis, Karnofsky performance score <90% at transplant, abnormal serum LDH at transplant, and chemotherapy resistance were adverse prognostic factors for outcome. Progression of Hodgkin's disease accounted for 69% of all deaths. Autotransplantation should be considered for patients with Hodgkin's disease in first relapse or second remission. Future investigations should focus on strategies designed to decrease relapse after autotransplantation, particularly in patients at high risk for relapse.

Adolescent↗

PubMed2000

Human cytomegalovirus immediate early proteins upregulate endothelial p53 function.

Infected endothelial cells are found to be resistant to apoptosis possibly mediated by p53 cytoplasmic sequestration. We explored whether the immediate early 84 kDa protein (IE84) of cytomegalovirus (CMV) is responsible for p53 cytoplasmic sequestration. The endothelial cells were transfected with plasmids containing IE1 and 2 coding regions which are known to synthesize IE84 and 72 proteins. Our study found that p53 expression was significantly elevated in endothelial cells transfected with IE1 and 2 plasmids. However, p53 was only found in the nucleus rather than sequestered in the cytoplasm. We have demonstrated that IE84 and 72 are not responsible for p53 dysfunction caused by CMV infection, rather they upregulate p53 function and promote endothelial apoptosis.

Apoptosis↗

PubMed2000

Enhancement of the anti-tumor activity of a peripheral blood progenitor cell graft by mobilization with interleukin 2 plus granulocyte colony-stimulating factor in patients with advanced breast cancer.

OBJECTIVE: Autologous interleukin 2 (IL-2)-activated natural killer (NK) cells kill a broad spectrum of tumor targets, including breast cancer. We hypothesized that mobilization with IL-2 and granulocyte colony-stimulating factor (G-CSF) for collection of peripheral blood progenitor cells (PBPC) may enhance the anti-tumor activity of the graft in autograft recipients. We determined the dose-limiting toxicity and maximum tolerated dose of subcutaneous IL-2 given with G-CSF for PBPC mobilization, the ability of IL-2 + G-CSF mobilized stem cells to reconstitute hematopoiesis, and the in vitro immunologic function of the graft in patients with advanced breast cancer. MATERIALS AID METHODS: Forty-three women with stage IIIA/B or metastatic breast cancer underwent mobilization of PBPC with IL-2 administered subcutaneously for 14 days along with G-CSF for the latter 7 days. IL-2 was given in a dose-escalated manner, with the maximum tolerated dose determined to be 1.75 x 10(6) IU/m(2)/day. Fifteen women with stage IIIA/B or metastatic breast cancer underwent G-CSF mobilization alone and served as a control group. RESULTS: [corrected] Fifty-two percent of the patients mobilized with 1L-2 at the maximum tolerated dose reached the target number of CD34(+) cells for transplantation with three aphereses compared to 93% of control patients who were mobilized with G-CSF alone. [corrected] There was no significant impact on time to engraftment of neutrophils or platelets using either mobilization regimen. The addition of subcutaneous IL-2 to mobilization increased the cytotoxicity of IL-2-activated mononuclear cells from the PBPC product against the breast cancer cell target, MCF-7, and increased the percentage of NK cells and activated T cells in the PBPC product. The enhanced NK cell number was sustained in the early posttransplant period. CONCLUSIONS: [corrected] IL-2 + G-CSF mobilization is safe, may lead to a more immunologically functional graft without impairing hematologic recovery, and thus merits further exploration to evaluate the clinical anti-tumor efficacy of these immunocompetent grafts. [corrected] Limitations of this combined approach to stem cell mobilization include a decrease in the number of CD34(+) cells mobilized with the combined cytokines and the short duration of the increased number of anti-tumor effector cells after transplant.

Adult↗

PubMed2000

Matched-pair analysis of peripheral blood stem cells compared to marrow for allogeneic transplantation.

We performed a case-control analysis of 42 patients with advanced leukemia or MDS comparing peripheral blood stem cell (PBSC) with marrow grafts (BMT) from HLA-matched sibling donors. PBSC were mobilized with G-CSF (7.5 microg/kg/day) and yielded a median of 6.7 x 10(6) CD34+ cells/kg (range, 1.6-15.0) and 2.7 x 10(8) CD3+ cells/kg (range, 1.1-7.1) vs marrow grafts with a median of 2.0 x 10(8) nucleated cells/kg (range, 1.8-2.2). Recovery was significantly faster after PBSCT compared to BMT, with a median of 17 (range, 12-26) vs 26 (range, 16-36) days, respectively, to neutrophils >0.5 x 10(9)/l (P < 0.01), and 22 (range, 12->60) vs 42 (range, 18->60) days, for platelet recovery (P < 0.01). Transplantation of >/=7 x 10(6) CD34+ cells/kg accelerated recovery to >20 x 10(9) l platelets; median 17 days (range, 12-19) vs 23 days (range, 17-36) for those receiving <7 x 10(6)/kg (P = 0.01). PBSC and marrow recipients had similar risks of grades II-IV or III-IV acute GVHD or extensive chronic GVHD (all P > 0.3). At 1 year after PBSCT and BMT, the risk of relapse was 41% and 32%, respectively (P = 0.47), and the probability of survival was 46% and 48%, respectively (P = 0.70). HLA-matched sibling PBSCT resulted in faster neutrophil and platelet engraftment compared to BMT, with no subsequent differences in acute or chronic GVHD, relapse or survival. A minimum of 7 x 10(6) CD34+ cells/kg in PBSC grafts may be required for very rapid platelet engraftment. Bone Marrow Transplantation (2000) 26, 723-728.

Adult↗

PubMed1999

Intercellular adhesion molecule-1 expression in endothelial cells is activated by cytomegalovirus immediate early proteins.

BACKGROUND: Human cytomegalovirus (HCMV) infection is associated with allograft vasculopathy and rejection. One potential mechanism is vascular injury from immunologically mediated processes. HCMV infection has been shown to increase the constitutive expression of intercellular adhesion molecule-1 (ICAM-1). The objective of this study was to determine the molecular basis of HCMV enhanced ICAM-1 gene expression in endothelial cells using human umbilical vein endothelial cells (HUVECs) as a model. METHODS: HUVECS were infected with HCMV virus and the level of ICAM-1 mRNA determined over time. HUVECS were then transiently transfected with plasmid constructs containing ICAM-1 and HCMV immediate early (IE) gene sequences and the effect of IE proteins on ICAM-1 promoter expression determined. Antibodies to cytokines known to be affected by HCMV IE proteins or to modulate ICAM-1 expression were added to determine if cytokines were mediating ICAM-1 expression. RESULTS: Infection of HUVECs with HCMV resulted in a rapid rise in ICAM-1 mRNA levels, suggesting that the viral IE proteins were involved in gene activation. The HCMV IE1 and IE2 proteins synergistically activated both transfected and endogenous ICAM-1 gene expression. The addition of antibodies to interleukin-1, tumor necrosis factor-a, transforming growth factor-beta, or interleukin-6 had no effect on the IE protein-mediated increase in ICAM-1 expression. Deletion analysis of the ICAM-1 gene promoter revealed that a minimum of 370 base pairs of 5' flanking sequences was required for maximal transactivation by IE proteins; mutation analysis showed that an NFkappaB site at base pairs -187 to -178 was not required for promoter activation. CONCLUSIONS: These results demonstrate that HCMV regulates the heterologous ICAM-1 gene promoter in endothelial cells not via cellular cytokine production, but rather by a direct effect of IE proteins, and supports a model in which HCMV IE gene products interact with ICAM-1 promoter elements to increase gene expression.

Base Sequence↗

PubMed1999

Natural killer cell cytotoxicity of breast cancer targets is enhanced by two distinct mechanisms of antibody-dependent cellular cytotoxicity against LFA-3 and HER2/neu.

Treatment of advanced breast cancer with autologous stem cell transplantation is limited by a high probability of disease relapse. In clinical trials, interleukin 2 (IL-2) alone can expand natural killer (NK) cells in vivo and increase their cytotoxic activity against breast cancer cell lines, but this increase is modest. Understanding the mechanisms that mediate NK cell lysis of breast cancer targets may lead to improvements of current immunotherapy strategies. NK cells from normal donors or patients receiving subcutaneous IL-2 were tested in cytotoxicity assays against five breast cancer cell lines. The role of adhesion molecules and antibodies that interact through Fc receptors on NK cells was explored. NK cell lysis of breast cancer targets is variable and is partially dependent on recognition through ICAM-1 and CD18. While blocking CD2 slightly decreased cytotoxicity, contrary to expectations, an antibody against CD58 (the ligand for CD2), failed to block killing and instead mediated an increased cytotoxicity that correlated with target density of CD58. The CD58 antibody-enhanced killing was dependent not only on FcRgammaIII but also on CD2 and ICAM-1/CD18. To further elucidate the mechanism of this CD58 antibody-dependent cellular cytotoxicity (ADCC), another antibody was tested. Trastuzumab (Herceptin), a humanized antibody against HER2/neu, mediated potent ADCC against all the HER2/neu positive breast cancer targets. Unlike CD58 antibody-mediated ADCC, Herceptin ADCC was minimally affected by blocking antibodies to CD2 or ICAM-1/CD18, which suggests a different mechanism of action. This study shows that multiple mechanisms are involved in NK cell lysis of breast cancer targets, that none of the targets are inherently resistant to killing, and that two distinct mechanisms of ADCC can target immunotherapy to breast cancer cells.

Antibodies↗

PubMed1999

A novel four-drug ablative regimen with hemopoietic stem cell rescue for patients with breast cancer: a phase II study.

High-dose chemotherapy and autologous hemopoietic stem cell transplantation (HSCT) may provide durable progression-free survival in some patients with stage IV breast cancer (S4Brca). We have studied a new four-drug intensive preparative regimen with HSCT in a group of 158 women with S4Brca to define the risk and potential benefit of this regimen in this patient population. From May 1988 through May 1997, 158 women with S4Brca at a single center were treated with cisplatin, etoposide, thiotepa, and cyclophosphamide (PETCy) plus autologous HSCT Eligible patients were also treated with posttransplant involved-field radiation therapy. Patients with estrogen-receptor positive tumors not previously treated with tamoxifen also received this therapy for 5 years following transplantation. All patients experienced significant toxicity requiring blood-product support and parenteral nutrition. Eighteen patients (11%) died of regimen-related toxic events. With a median follow-up of 540 days for surviving patients, a retrospective Kaplan-Meier analysis projects an overall survival of 38+/-8.5% (95% CI) at 890 days with a maximum follow-up of 8.8 years. For 52 patients in sensitive relapse, the median event-free survival time is 767 days, with 46.2+/-15.3% (95% CI) predicted to be alive at 884 days with a maximal follow-up of almost 9 years. Nearly one-half of patients in this study with S4Brca in sensitive relapse have experienced durable remissions following PETCy ablation and HSCT. Although toxicity is significant, the PETCy regimen produces a favorable balance between efficacy (event-free survival) and treatment failure (relapse + regimen-related toxic death) compared with published results. These data suggest that within the high-dose range for preparative therapy, a steep dose-response may exist for breast cancer. Trials comparing the dose intensity of preparative regimens are warranted.

Adult↗

PubMed1997

Therapy of patients with T-cell lymphomas and leukemias using an anti-CD7 monoclonal antibody-ricin A chain immunotoxin.

Anti-CD7-dgA, DA7, consists of deglycosylated ricin A chain coupled to a mouse monoclonal anti-human CD7 antibody. This study determined the maximally tolerated dose (MTD) of this immunotoxin administered as a one hour infusion over five days to 11 patients with T-cell lymphoma (>30% CD7+ malignant cells). The MTD was 0.2 mg/kg/day or 1 mg/kg/120 hours (maximal toxicity grade 3) with vascular leak syndrome (VLS) as dose-limiting toxicity (DLT). Predictors of severe VLS included age and absence of circulating lymphoma cells. Two partial responses and one minimal response were seen. Patients with minimal lymphoma burden or T-cell large granular lymphocyte (LGL) leukemia showed the best responses. The mean maximal serum concentration of immunotoxin at the MTD was 2.5 ug/ml. The mean alpha-phase half-life was 1.5 hours and the mean beta-phase half-life was 8 hours. Repeated dosing had minimal effects on either peak serum immunotoxin concentrations or serum half-lives. While human antimouse antibodies were observed, they were low in concentration (<55 ng/ml). Human anti-ricin antibody was elevated in one patient (190 ng/ml). VLS presented with hypoalbuminemia, dyspnea, pulmonary edema, aphasia, and peripheral edema and cleared over a two week period. Serum fibronectin levels were measured in three patients and were very low in one patient who developed VLS. No specific binding of DA7 immunotoxin was seen with vascular endothelium in various human tissues.

Adolescent↗

PubMed1997

Low dose subcutaneous interleukin-2 after autologous transplantation generates sustained in vivo natural killer cell activity.

Autologous transplantation can induce extended remission in some patients with advanced breast cancer and lymphoma yet nearly 80% and 50%, respectively, will ultimately relapse. In vitro studies suggest that activated natural killer cells (NK) mediate lytic activity against breast cancer and lymphoma cell lines. Therefore, immunotherapy with interleukin-2 (IL-2, Amgen) to activate NK may improve long-term disease-free survival when administered in a post-transplant minimal residual disease setting. To determine the feasibility of administering IL-2 and activation of NK post-transplant, twelve patients (6 breast cancer, 6 lymphoma) were enrolled on a phase I dose escalation study after autologous transplantation (median day + 94, range 50-166). IL-2 was self administered at 0.25 x 10(6) (n = 6) or 0.5 x 10(6) (n = 6) U/m2/day subcutaneously for 84 consecutive days. The best tolerated dose was 0.25 x 10(6) U/m2/day (75% of planned doses given vs. 48% at the higher dose). Dose limiting toxicity occurred in 6 patients (n = 2 at 0.25 x 10(6) U/m2/day, n = 4 at 0.5 x 10(6) U/m2/day) consisting of decreased performance status (n = 2), thrombocytopenia (n = 3, 1 at the lower dose), and mild neutropenia (n = 1 at the lower dose). However, all symptoms resolved within a week following discontinuation of IL-2 and no patient required hospitalization. Circulating soluble IL-2 receptor levels were significantly increased in all patients receiving IL-2. Patients receiving at least 28 days of IL-2 exhibited a greater than 10-fold increment in circulating CD56+bright/CD3- NK. Furthermore, lytic function was increased against NK resistant targets, MCF-7 (breast cancer), and Raji (lymphoma). In vivo IL-2 primed NK cells obtained by lymphapheresis were activated in large-scale ex vivo incubation in high dose IL-2 (1,000 U/mL) at high cell density (10 x 10(6)/mL), in gas permeable bags, and using serum-free media. NK lytic function against MCF-7 and Raji targets was further enhanced. We conclude that low dose subcutaneous IL-2 based immunotherapy is feasible, relatively safe, can be administered in an outpatient setting and hypothesize that additional ex vivo incubation in IL-2 may be used to generate NK cells with potent antitumor effects in vivo.

Adjuvants, Immunologic↗

PubMed1996

Laboratory preparation of a deglycosylated ricin toxin A chain containing immunotoxin directed against a CD7 T lineage differentiation antigen for phase I human clinical studies involving T cell malignancies.

An immunotoxin consisting of a monoclonal antibody specific for CD7, a cell surface determinant expressed on T acute lymphocytic leukemia (T-ALL) blast cells, was linked to the potent plant toxin deglycosylated ricin toxin A chain (dgRTA) and is currently under evaluation in phase I clinical trials. Scale-up production of this immunotoxin, called DA7, was simplified using a two-step purification protocol that resulted in a highly purified immunotoxin meeting FDA criteria for IND approval. The anti-CD7 antibody, 3Ale, an IgG2b, was coupled to toxin using two different heterobifunctional cross-linkers, (1) N-succinimidyl-3-(2-pyridyl-dithiolproprionate) (SPDP), considered a standard croslinker and (2) 4-succinimidyloxycarbonyl-alpha-methyl-alpha-(2-pyridyldithio)tolu ene (SMPT), designed to hinder the in vivo breakdown of the toxin/antibody disulfide bond. Since experiments revealed that SPDP-DA7 had similar pharmacokinetics and biodistribution in mice and higher yields than DA7 made with a hindered cross-linker, SPDP-DA7 was scaled up for clinical study. Yield of SPDP-DA7 was 25% relative to starting material. Fractions were collected containing a toxin: antibody ratio of 1:1 to 4:1 rather than only a 1:1 ratio since studies showed that this heterogenous fraction was just as toxic to proliferating CD7-expressing leukemia cells as a homogeneous 1:1 fraction. In vitro, the concentration of heterogenous SPDP-DA7 selectively inhibiting 50% activity (IC50) of the CD7+ CEM cell line was 0.01 microgram/ml to 0.05 microgram/ml for inhibiting activated T cells or T cell lines. In vivo, SPDP-DA7 showed a significant anti-tumor effect against CEM cells administered to scid/scid mice, but even more importantly was effective against primary T cell leukemias taken from patients and injected into scid/scid mice.

Animals↗

PubMed1996

Cytoplasmic sequestration of p53 in cytomegalovirus-infected human endothelial cells.

Human umbilical vein endothelial cells were infected with human cytomegalovirus (HCMV) at a multiplicity of infection of 0.1 plaque-forming unit/cell and remained > 95% viable even after 10 days of infection. To induce apoptosis, control human umbilical vein endothelial cells and cells infected with HCMV for 3, 5, and 7 days were serum starved for 48 hours. Almost one-half of the uninfected cells lost viability after 48 hours of serum starvation whereas HCMV-infected cells were virtually unaffected (< 20% death, P < 0.05). Uninfected cells showed typical hallmarks of apoptosis, including unique morphological changes and DNA laddering. HCMV-infected cells, concomitant with their resistance to serum-starvation-induced death, displayed almost none of these characteristics. Active replication of HCMV was necessary for the anti-apoptotic effect, as cells treated with ultraviolet light-inactivated virus were not protected. p53, the G1/S phase cell cycle brake protein, was elevated in HCMV-infected cells. However, rather than accumulating in the nucleus, immunofluorescent and Western blot studies demonstrated remarkable and predominant cytoplasmic sequestration of p53 in HCMV-infected endothelial cells. Although HCMV proteins have already been shown to block apoptosis, we suggest that the aberrant subcellular pattern of p53 is the disturbed cellular mechanism that may be responsible for the anti-apototic properties of HCMV-infected cells. The selective resistance to apoptosis can be important during HCMV replication and may explain the oncogenic potential of HCMV as well as its pathogenic role in intimal-proliferation-mediated vascular diseases.

Cells, Cultured↗