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Biomedical subjects

F R Appelbaum

Publications and source records attributed to F R Appelbaum.

At least 289 records · Page 16Linked to original sources
PubMed1992

Etoposide, cyclophosphamide and fractionated total body irradiation as a preparative regimen for marrow transplantation in patients with advanced hematological malignancies: a phase I study.

Thirty-seven patients with advanced hematologic malignancy were entered into a phase I study designed to define a maximum tolerable dose (MTD) of etoposide (VP-16) and cyclophosphamide (CY) combined with 12 Gy fractionated total body irradiation (TBI) as preparation for marrow transplantation from an HLA-identical sibling (n = 13) or with cryopreserved autologous marrow (n = 24). Dose levels ranged from 36 mg/kg of VP-16 combined with 67 mg/kg of CY to 52 mg/kg of VP-16 combined with 103 mg/kg of CY followed by 12 Gy TBI. The MTD for allogeneic marrow recipients was 36 mg/kg of VP-16 + 52 mg/kg of CY followed by 12 Gy TBI and for autologous marrow recipients 44 mg/kg of VP-16 + 103 mg/kg CY followed by 12 Gy TBI. Pulmonary and liver toxicities were dose limiting. All of 31 evaluable patients transplanted in relapse achieved a complete remission. However, in all but three of these patients the disease relapsed 28-899 (median 110) days post-transplant. Currently, six of 24 autologous marrow recipients are surviving, three in remission 256, 340 and 764 days post-transplant. None of 12 allogeneic marrow recipients have survived. In conclusion, a preparative regimen combining 44 mg/kg of VP-16 + 103 mg/kg CY followed by 12 Gy TBI is well tolerated by autologous marrow recipients and 36 mg/kg VP-16 + 67 mg/kg CY followed by 12 Gy TBI is well tolerated by allogeneic marrow recipients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

Is there a better way to deliver total body irradiation?

The available data suggest that the antileukemic, immunosuppressive and toxic effects of TBI are highly dose dependent and if TBI is given as single daily fractions at 5-10 cGy/minute, an optimal dose for the treatment of most leukemias is somewhere between 12 and 16 Gy. Giving radiation as a single dose rather than fractionating it increases both its immunosuppressive as well as its toxic effects. The relative anti-leukemic effects of single vs. fractionated irradiation are less clear, but available data support the view that fractionation does not substantially reduce the effects of TBI on myeloid tissue. Increasing the dose rate increases toxicities and, although data are not yet complete, likely increases both immunosuppressive and anti-tumor effects. The impact of total dose, dose fractionation and dose rate are highly interdependent and how best to manipulate these 3 factors to lead to an optimal combination is as yet unknown. Directing radiotherapy to sites of leukemia using monoclonal antibodies or other carriers such as growth factors is feasible and, although there are many aspects of this approach which have yet to be worked out, targeted radiotherapy may prove to be the best way to achieve the therapeutic goals of increased tumor ablation and immunosuppression without increased toxicities.

Bone Marrow Transplantation↗
PubMed1991

Retrovirus-mediated gene transduction into long-term repopulating marrow cells of dogs.

Amphotropic helper-free retrovirus vectors containing the bacterial neomycin phosphotransferase gene (neo) and the human adenosine deaminase gene (adenosine aminohydrolase, EC 3.5.4.4; ADA) were used to transduce canine marrow cells. In one approach, dogs were treated for 7 days with recombinant human granulocyte colony-stimulating factor to stimulate hematopoietic cell division. Bone marrow cells were collected and transduced by 24 hours of cocultivation on vector-producing cells followed by incubation in a vector-containing long-term marrow culture system for 4 days. Transduced autologous marrow (0.4 to 1.0 x 10(8) cells/kg) was infused into dogs administered otherwise lethal total body irradiation (TBI) of 920 cGy. Two of four dogs engrafted, and their marrows showed intermittently between 1% and 11% G418-resistant colony-forming unit granulocyte-macrophage (CFU-GM) colonies for up to 2 years after transplantation. In a different experimental approach, autologous marrow, obtained at the time of the PB neutrophil nadir 7 days after a single cyclophosphamide injection (40 mg/kg intravenously), was cocultivated for 24 hours on vector-producing cells and infused at doses of 0.06 to 0.18 x 10(8) cells/kg into dogs administered 920 cGy TBI. One of three dogs engrafted, and the marrow showed intermittently 1% to 10% G418-resistant CFU-GM colonies for at least 2 years. Culture results were confirmed by polymerase chain reaction (PCR) showing the presence of the neo gene in marrow cells, peripheral blood (PB) granulocytes, and PB and lymph node lymphocytes. Dilution experiments indicated that up to 10% of marrow, lymph node, and PB cells contained the neo gene, consistent with the culture results. Samples harboring the neo gene also contained the gene for human ADA. However, repeated analyses of PB and marrow cells for human ADA gene expression by starch gel electrophoresis were negative. PB samples of all dogs were free of helper virus, and no long-term side effects from the transduction were observed.

3T3 Cells↗
PubMed1991

Biodistribution and dosimetry following infusion of antibodies labeled with large amounts of 131I.

Dosimetry and treatment planning for therapeutic infusions of radiolabeled antibodies are usually performed by extrapolation from the biodistribution of trace-labeled antibody. This extrapolation assumes that the biodistribution of high specific activity antibody will be similar to that seen with trace-labeled antibody. However, high doses of radiation result in rapid depletion of lymphoid and hematopoietic cells in lymph nodes, spleen, and marrow with replacement by blood and plasma. If radiolabeled antibody is cleared slowly from blood, this replacement may result in increased radionuclide concentrations in these tissues following infusions of antibody labeled with large amounts of radionuclide. To examine the influence of deposited radiation on the biodistribution of radiolabeled antibody, we treated mice with a constant amount of antibody that was labeled with varying amounts of 131I. Survival was determined in normal specific pathogen-free AKR/Cum mice (Thy1.2+) after infusion of anti-Thy1.1 antibody labeled with 10 to 6500 muCi of 131I, to determine an appropriate range of 131I doses for further study. The dose producing 50% lethality within 30 days following infusion of 131I-labeled antibody was 530 muCi 131I. Biodistribution, bone marrow histology, and dosimetry were subsequently determined after infusion of 500 micrograms of antibody labeled with 10, 250, 500, or 3500 muCi 131I. The amount of 131I did not influence uptake or retention of antibody in blood, liver, lung, or kidney. In contrast, infusion of antibody labeled with 250 to 3500 muCi of 131I led to a dose-related increase in the concentration of 131I in marrow, spleen, lymph node, and thymus. For example, at 96 h after infusion of antibody labeled with 500 or 3500 muCi 131I, concentrations in marrow were 3- to 4-fold higher than after infusion of trace-labeled antibody. The increase in marrow 131I concentrations was associated with depletion of cells and hemorrhage within the marrow space. As a result, estimated mean absorbed doses to marrow, lymph node, spleen, and thymus were 1.2 to 3.1 times higher than would have been predicted from the biodistribution of trace-labeled antibody. These results suggest that the biodistribution of trace-labeled antibody should be an accurate predictor of the behavior of high specific activity antibody in blood and solid organs such as liver and kidney. In contrast, radiation from antibody labeled with large amounts of radionuclide can result in an alteration of the concentration of radiolabeled antibody in rapidly responding tissues such as marrow.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1991

Recombinant human stem cell factor, a c-kit ligand, stimulates hematopoiesis in primates.

Recombinant human stem cell factor (SCF) is homologous with recombinant rat SCF (rrSCF) and is a ligand for c-kit. We determined the influence of SCF on hematopoiesis in vitro and in vivo in baboons. In vitro, SCF alone stimulated little growth of hematopoietic colony-forming cells from baboon marrow, but did increase the number of colonies formed in response to erythropoietin (Epo), interleukin-3 (IL-3), and granulocyte-macrophage colony-stimulating factor (GM-CSF). In vivo, SCF caused an increase in the peripheral blood of the number of erythrocytes, neutrophils, lymphocytes, monocytes, eosinophils, and basophils. In marrow, it caused an increase in marrow cellularity and in the absolute number of colony-forming unit-granulocyte-monocyte (CFU-GM) and burst-forming unit-erythroid (BFU-E) in marrow following infusion of SCF. The in vivo stimulation of multiple lymphohematopoietic lineages corroborates previous in vitro studies and suggests a potentially important clinical role for SCF.

Animals↗
PubMed1991

Late failure of autologous marrow grafts in lethally irradiated dogs given anti-class II monoclonal antibody.

We established a model of canine marrow autografts after 9.2 Gy total body irradiation (TBI) to study the role of class II antigens in hematopoietic stem cell growth and differentiation. Twenty dogs were given 9.2 Gy TBI, marrow, and intravenous (IV) murine anti-class II monoclonal antibody (MoAb). Infusion of 0.6 mg/kg/d of MoAb H81.98.21, an IgG2a reactive with HLA-DR, on days 0 to 4 after TBI did not prevent initial engraftment, but dogs died with late graft failure. MoAb B1F6, an IgG2a reactive with HLA-DR + DP, had no adverse effect on engraftment, although both MoAbs detect antigens on stem cells. The critical time for the effect of MoAbs is the first 4 days after transplantation. Our findings argue against several pathogenetic mechanisms, including removal of MoAb-coated stem cells by the reticuloendothelial system (RES), canine complement-mediated cytotoxic effects on stem cells, antibody-dependent cellular cytotoxicity, and inactivation of MoAb-coated cells by dog anti-mouse antibody. To distinguish between MoAb-induced damage to microenvironment (ME)/accessory cells (AC) and late graft failure from a lack of pluripotent stem cells, three dogs were given TBI, a marrow autograft, and MoAb H81.98.21 on days 0 to 4; one, given thoracic duct cells on day 6, developed graft failure; the other two, given marrow depleted of AC by L-leucyl L-leucine o-methyl ester (Leu-Leu-OMe), had sustained grafts. Findings support the notion that originally transplanted pluripotent stem cells are no longer present on day 6 and that the ME is functional and able to support newly injected stem cells.

Animals↗
PubMed1991

Radiolabeled anti-CD45 monoclonal antibodies target lymphohematopoietic tissue in the macaque.

Despite bone marrow transplantation, many patients with advanced leukemia subsequently relapse. If an additional increment of radiation could be delivered to lymphohematopoietic tissues with relative specificity, the relapse rate may decrease without a marked increase in toxicity. We have examined the biodistribution of two 131I-labeled monoclonal antibodies reactive with the CD45 antigen in Macaca nemestrina. Three animals received 0.5 mg/kg BC8, an IgG1 of low avidity (6 x 10(7) L/mol). Three received 0.5 mg/kg AC8, an IgG2a of moderate avidity (5 x 10(8) L/mol), and two received 4.5 mg/kg AC8. Estimates of radiation absorbed dose demonstrated that these antibodies could deliver up to five times more radiation to lymph nodes, and up to 2.6 times more to bone marrow, than to lung or liver. The higher avidity AC8 antibody at 0.5 mg/kg was cleared more rapidly from blood and resulted in lower antibody uptake in lymph nodes than did BC8 at 0.5 mg/kg. Increasing the dose of AC8 to 4.5 mg/kg resulted in slower blood clearance and higher lymph node uptake. These studies suggest that radiolabeled anti-CD45 antibodies can deliver radiation with relative specificity to lymphohematopoietic tissues. This approach, in combination with marrow transplantation, may improve treatment of hematologic malignancies.

Animals↗
PubMed1991

Phase I-II trial of pentoxifylline for the prevention of transplant-related toxicities following bone marrow transplantation.

Disease relapse and transplant related toxicities have limited the application of bone marrow transplantation (BMT) in the treatment for hematologic malignancies. Because elevated levels of tumor necrosis factor alpha (TNF-alpha) have been correlated with the development of transplant related complications, we conducted a phase I-II trial of pentoxifylline (PTX), a xanthine derivative capable of down-regulating TNF-alpha production, in patients with hematologic malignancies undergoing BMT. Thirty consecutive adult patients (median age, 34) were entered and received either an allogeneic (n = 26) or autologous (n = 4) BMT. Patients were enrolled at increasing dose levels (1,200, 1,600, and 2,000 mg/d) from day -10 through day +100 posttransplant. PTX was well tolerated with no significant adverse side effects noted at any of the dose levels administered. The actuarial day 100 survival for these 30 patients was 90% (95% confidence interval 79% to 100%). When compared with a good risk control group, PTX recipients experienced less mucositis (3.7 +/- 1.1 v 18.7 +/- 1.1 days, P = .004), less hepatic venocclusive disease (10% v 65%, P = .001), a lower incidence of renal insufficiency (3% v 65%, P = .0003), required less days of total parenteral nutrition (TPN) (24.0 +/- 1.3 v 35.0 +/- 2.4, P = .001) and were discharged from the hospital earlier than controls (day 26.0 +/- 1.8 v 37.0 +/- 3.8, P = .01). In addition the incidence of graft-versus-host disease (GVHD) greater than or equal to grade II was also reduced among the PTX recipients (35% v 68%, P = .03). PTX at doses in excess of 1,200 mg/d further reduced the severity of mucositis, and TPN requirements resulting in earlier hospital discharge than patients receiving 1,200 mg/d of PTX. In this study oral administration of PTX in doses up to 2,000 mg/d was well tolerated and associated with a reduction in morbidity and mortality in patients undergoing BMT. Prospective randomized trials are currently in progress to test these preliminary observations.

Acute Disease↗
PubMed1991

Phase I/II trial of recombinant human granulocyte-macrophage colony-stimulating factor following allogeneic bone marrow transplantation.

Forty-seven patients with hematologic neoplasia received recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF) by daily 2-hour infusion following allogeneic bone marrow transplantation from HLA-identical sibling donors in a phase I-II dose-escalation trial. Dose levels ranged from 30 to 500 micrograms/m2/d. At doses at or below 250 micrograms/m2/d, toxicity felt to be caused by rhGM-CSF was negligible. However, three of five patients treated with 500 micrograms/m2/d had unacceptable side effects caused by rhGM-CSF. Two different graft-versus-host disease (GVHD) prophylactic regimens were administered. Twenty-seven evaluable patients were administered regimens that did not contain methotrexate (MTX) (Group I) and reached an absolute neutrophil count of 1,000/microL by a median of day 14. In contrast, 18 patients who received GVHD prophylactic regimens containing MTX (Group II) reached an absolute neutrophil count of 1,000/microL on a median of day 20. Patients in Group I had fewer febrile days and, of those discharged, had shorter initial hospitalizations than patients in Group II. The overall incidence of severe acute GVHD (grade 2 or greater) in the rhGM-CSF-treated patients was 28% and was similar to that in historical "good risk" patients who did not receive rhGM-CSF. These preliminary data suggest rhGM-CSF is unlikely to exacerbate GVHD in HLA-identical sibling donor transplants and indicate the need for randomized trials of rhGM-CSF in allogeneic marrow transplant patients.

Adolescent↗
PubMed1991

Allogeneic marrow transplantation in patients with chronic myeloid leukemia in the chronic phase: a randomized trial of two irradiation regimens.

A randomized trial was performed to compare two regimens of total body irradiation in patients with chronic myeloid leukemia treated by allogeneic marrow transplantation while in the chronic phase. All patients received cyclophosphamide 120 mg/kg followed by total body irradiation and marrow from HLA-identical siblings. Cyclosporine and methotrexate were used for prophylaxis against acute graft-versus-host disease. Fifty-seven patients were randomized to receive 2.0 Gy fractions of irradiation daily for 6 days and 59 were randomized to receive 2.25 Gy fractions daily for 7 days. The probabilities of relapse at 4 years were 0.25 for the 12.0 Gy group and 0.00 for the 15.75 Gy group (P = .008). The actuarial probabilities of survival and relapse-free survival at 4 years were 0.60 and 0.58 among the patients who received 12.0 Gy compared with 0.66 and 0.66 for those who received 15.75 Gy. The 4-year probabilities of transplant-related mortality were 0.24 and 0.34 respectively (P = .13) while the probability of moderate to severe acute graft-versus-host disease was 0.33 for the 12.0 Gy group and 0.44 for the 15.75 Gy group (P = .15). The lower relapse probability in the patients receiving the higher dose of total body irradiation did not result in improved survival because mortality from causes other than relapse was increased.

Adult↗
PubMed1991

A retrospective analysis of therapy for acute graft-versus-host disease: secondary treatment.

We have reviewed results of secondary therapy in 427 patients with acute graft-versus-host disease (GVHD) who did not have a durable satisfactory response after primary treatment. At the beginning of secondary treatment, 320 patients (75%) had rash, 252 (59%) had liver dysfunction, and 228 (53%) had gut dysfunction. Secondary treatment was with glucocorticoids (n = 249), cyclosporine (n = 80), antithymocyte globulin (n = 114), or monoclonal antibody (n = 19) either singly (n = 390) or in combination (n = 37). Parameters of GVHD severity were recorded weekly, and responses were determined according to values at the initiation of tertiary treatment or, for patients without such treatment, using values on day 29 of secondary treatment or the last recorded values before death, whichever occurred first. Minimal criteria for improvement or deterioration were defined for each organ, but no attempt was made to define liver or gut outcome if another complication such as venocclusive disease or infectious enteritis was present. Improvement or resolution of GVHD in the respective organ was seen in 45% of patients with skin disease, 25% of patients with evaluable liver disease, and in 35% of patients with evaluable gut disease. Overall complete or partial responses were seen in 40% of patients. The highest complete response rate with secondary therapy (23%) was seen when GVHD recurred during the taper phase of primary glucocorticoid treatment and was managed by increasing the dose of glucocorticoids. Multivariate analyses were performed to identify patient, disease, or treatment factors associated with likelihood of complete response or overall improvement. A similar analysis was performed to identify covariates associated with time to treatment failure (defined as initiation of tertiary therapy or death not due to relapse of malignancy). Severe dysfunction in the skin, liver, and gut at the beginning of treatment was associated both with a decreased likelihood of complete response and an increased treatment failure rate. The times to treatment failure and the proportions of patients in various response categories were similar for primary and secondary treatment, suggesting that the potential efficacy of new immunosuppressive agents for treatment of acute GVHD can be assessed meaningfully in patients who have not responded adequately to initial therapy.

Adult↗
PubMed1991

Prevention of transfusion-induced sensitization to minor histocompatibility antigens on DLA-identical canine marrow grafts by gamma irradiation of marrow donor blood.

Dogs given total-body irradiation and marrow transplants from DLA-identical littermates exhibit prompt and sustained hematopoietic engraftment. However, animals given three preceding blood transfusions from the marrow donor before transplant become sensitized and reject the marrow graft. Rejection is due to exposure to polymorphic minor non-DLA histocompatibility antigens expressed on blood mononuclear cells. We sought to determine whether heat treatment would prevent blood from sensitizing recipients in this model since heating blood to 45 degrees C for 45 min abrogates the ability of blood mononuclear cells to stimulate in mixed lymphocyte culture. Three of 4 evaluable dogs given heat-treated blood before transplant rejected their marrow grafts. To prevent possible reexpression/reacquisition of mononuclear cell functional activity in vivo after transfusion, subsequent dogs were given heated blood that was additionally exposed to 2000 cGy gamma irradiation. Eight of 10 evaluable dogs given blood treated in this fashion engrafted. Unexpectedly, 9 out of 10 evaluable dogs transfused with blood treated only with gamma irradiation also engrafted. These results demonstrate that treatment of blood with gamma irradiation alone or in combination with heat prevents transfusion-induced sensitization to minor histocompatibility antigens. Results from this canine model suggest that blood products be gamma irradiated before transfusion in patients who are transplant candidates in order to prevent sensitization to minor histocompatibility antigens and reduce the risk of marrow graft rejection.

Animals↗