Combination of chemotherapy and monoclonal antibodies for the treatment of lymphoma

Monoclonal antibodies (MoAbs) have transformed the treatment of lymphomas. The first reports of studies using MoAbs appeared 8 years ago, and current therapy for lymphoma patients usually includes treatment with MoAbs once or several times during the course of their disease. This review covers the use of MoAbs in combination with chemotherapy for the treatment of patients with lymphoma. Rituximab, an unconjugated anti-CD20 chimeric antibody, is certainly the most widely used MoAb, but the use of other unconjugated or radiolabeled MoAbs is increasing quickly. MoAbs are effective if used alone, but the duration of effectiveness is limited. Therefore, when MoAbs are used in curative treatment, they are combined with chemotherapy. There are randomized studies demonstrating the benefit of adding MoAbs to the treatment regimen of patients with diffuse large B-cell lymphoma, but results of ongoing studies regarding the benefit in other lymphomas have not been reported. Many questions must be answered before the best setting for MoAbs in the treatment of lymphoma patients can be determined.     

Differential diagnosis of chronic lymphocytic leukemia and diffuse well-differentiated lymphoma using monoclonal antibodies

Diffuse well-differentiated lymphocytic lymphoma (DWDL) with leukemic change and chronic lymphocytic leukemia (CLL) are not significantly different in morphology, immunophenotype and clinical course. Two monoclonal antibodies (MoAbs), designated L20 and A01, were established with respective reactivity against DWDL and CLL cells. The L20 MoAb reacted with both DWDL and CLL cells, and 20-50% of normal B cells. The second MoAb, A01, reacted not only with CLL cells but also with 33% of non-T, non-B cells. Immunoprecipitation patterns of L20 and A01 MoAbs against 125I-surface-labeled BALL and Daudi cell extracts revealed respective bands with molecular weights of 86 and 66 kilodaltons. These results showed that DWDL and CLL cells are different in nature, and that these two MoAbs can be used to distinguish DWDL from CLL cells.     

Integration of monoclonal antibodies and immunoconjugates into the treatment of acute myeloid leukemia

PURPOSE OF REVIEW: This review addresses use of monoclonal antibodies and immunoconjugates to treat acute myeloid leukemia. RECENT FINDINGS: Monoclonal antibodies used in acute myeloid leukemia have been directed against the antigens CD33, CD45, and CD66. Unconjugated monoclonal antibodies such as lintuzumab have modest activity against overt acute myeloid leukemia but can eliminate minimal residual disease in acute promyelocytic leukemia. Most experience with immunoconjugates is with gemtuzumab ozogamicin, an anti-CD33 monoclonal antibody linked to the potent antitumor antibiotic calicheamicin. Gemtuzumab ozogamicin has shown activity both singly, particularly in acute promyelocytic leukemia, and combined with conventional cytotoxic chemotherapy. Radiolabeled monoclonal antibodies against CD45 and CD66 have also been used to intensify the conditioning regimen before stem cell transplantation. The most promising results were obtained with radiolabeled anti-CD45 antibodies. Antibodies reactive with CD66 have been used to deliver targeted radiation to hematopoietic tissues in patients with advanced myeloid malignancies. SUMMARY: Both unlabeled monoclonal antibodies and immunoconjugates appear to have a limited role if used as single agents to treat acute myeloid leukemia. These agents hold promise as potentially useful additions to conventional therapy, but the optimal dosing and timing remain to be defined.     

Chemotherapy combinations with monoclonal antibodies in non-Hodgkin's lymphoma

Although the use of monoclonal antibodies as single agents has had a tremendous impact on the care of patients with non-Hodgkin's lymphoma (NHL), the greatest benefit has been generated by the addition of monoclonal antibodies to conventional cytotoxic chemotherapy. Rituximab is the monoclonal antibody responsible for all clinical improvement noted to date. The addition of rituximab to cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) chemotherapy (R-CHOP regimen) improves the response rate, progression-free survival (PFS), and overall survival (OS) in diffuse large B-cell lymphoma (DLBCL). Adding rituximab to CHOP chemotherapy improves response rates and PFS in mantle cell lymphoma (MCL). Finally, the addition of rituximab to a variety of chemotherapy regimens improves the response rates, PFS, and OS in follicular lymphoma (FL). Several other (epratuzumab, bevacizumab, alemtuzumab) monoclonal antibody-chemotherapy combinations are currently under study in NHL. This review will summarize the data supporting the addition of rituximab to chemotherapy in NHL and discuss preliminary data regarding the use of other monoclonal antibodies in combination with chemotherapy.     

Novel and engineered anti-B-cell monoclonal antibodies for non-Hodgkin's lymphoma

Over the past decade, the safety and efficacy of the anti-CD20 antibody rituximab has resulted in its use in virtually all patients with B-cell non-Hodgkin's lymphoma (NHL). Unfortunately, many patients who initially benefit from rituximab develop resistance while others may never respond. Both the successes and limitations of rituximab have heralded an explosion in research and development of novel monoclonal antibodies. Strategies employed to improve upon rituximab have included developing antibodies to target new epitopes of CD20 and new antigens, humanizing or creating fully human antibodies, and engineering antibodies with a potentially greater capacity for interaction with the host immune system. Each of these strategies has shown varying degrees of preclinical and clinical success. In this review we discuss the rationale for various strategies and report results from clinical trials employing these agents.     

Retention of B-cell-specific monoclonal antibodies by human lymphoma cells

The rates of endocytosis, intracellular degradation, and cell-surface shedding of 125I-labeled monoclonal antibodies (MoAbs) HD-37 (anti- CD19), B1 (anti-CD20), MB-1 (anti-CD37), BC8 (anti-CD45), and DA4-4 (anti-mu) by B-lymphoma cells were compared by cellular radioimmunoassay, ultrastructural autoradiography, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and thin layer chromatography using biopsy specimens from 12 patients with non- Hodgkin's lymphomas. 125I-BC8 was stably retained on the surface of lymphoma cells without appreciable internalization or shedding, whereas 125I-DA4-4 underwent rapid endocytosis and degradation. 125I-B1 was not internalized or degraded by tumor cells, but rapidly dissociated from the cell surface in intact form. Moderate rates of endocytosis, intracellular metabolism, and cell-surface shedding were shown by 125I- HD37 and 125I-MB-1. The 3 patients with diffuse, small cleaved-cell lymphomas internalized and degraded antibodies more slowly than did patients with other histologic subtypes. These kinetic differences may be important in the selection of MoAbs for immunotoxin and radioimmunoconjugate therapy of B-cell malignancies.     

Anti-TNF-alpha monoclonal antibodies in the treatment of rheumatoid arthritis

INTRODUCTION: Current slow-acting anti-rheumatic drugs available for rheumatoid arthritis can fail for certain severe cases; some are used empirically. Improvements in our knowledge of its pathogenesis and advances in molecular biology have made it possible to develop partially selective immunotherapy approaches. CURRENT KNOWLEDGE AND KEY POINTS: Tumor necrosis factor-alpha (TNF-alpha) is a critical inflammatory mediator in rheumatoid arthritis and may therefore be a useful target for specific immunotherapy. This article summarizes clinical studies using anti-TNF-alpha antibodies. It appears that there is good evidence for both safety and beneficial effects of anti-TNF-alpha antibodies in short-term treatment of rheumatoid arthritis. FUTURE PROSPECTS AND PROJECTS: It remains to be determined whether specific blockade of a single inflammatory mediator may be useful in long-term management. Therapeutic strategies aimed at concomitantly interfering with multiple pathogenic pathways are currently under investigation.     

Cutaneous T cell lymphoma: characterization by monoclonal antibodies

Monoclonal antibodies to human T cells permit the characterization of the surface phenotype of cutaneous T cell lymphoma (CTCL). The majority of CTCL cells are reactive with OKT1 and OKT3 monoclonals, which identify peripheral T cells and mature thymocytes. The neoplastic cells also react with OKT4, which recognizes the inducer T cell subset; they are, however, unreactive with OKT5 monoclonal, which identifies cytotoxic/suppressor T cell subsets. These data are in agreement with previous functional studies demonstrating that CTCL is a neoplasm of inducer (helper) T cells.     

Autologous bone marrow transplantation for acute myeloid leukemia following in vitro treatment with neuraminidase and monoclonal antibodies

Although monoclonal antibodies (MoAbs) to CD15, especially PM-81, react with leukemic blasts from the majority of patients with acute myeloid leukemia (AML), a small subset of patients have cells that are CD15 negative or dim. We determined previously that neuraminidase will increase the reactivity of PM-81 with AML blasts, as well as blasts from many patients with acute lymphoblastic leukemia (ALL). In this report, we describe the laboratory results and clinical course of the first patient with AML whose harvested bone marrow was treated with neuraminidase prior to MoAbs and complement treatment. Neuraminidase increased the percentage of the patient's leukemia cells that reacted with PM-81 from 18% to 90% and more than doubled the percentage of AML blasts that were lysed by PM-81 and complement. The patient suffered no acute toxicity, engrafted rapidly, and was transfusion independent by day 21 post-ABMT. This report demonstrates the probable safety and efficacy of pretreatment of bone marrow with neuraminidase, and increases the number of patients with AML or ALL who may benefit from ABMT using marrow purging with MoAb to CD15.     

Advances in the use of monoclonal antibodies in the therapy of chronic lymphocytic leukemia

Monoclonal antibody (moAb)-based therapies are evolving as an integrated component in the treatment of chronic lymphocytic leukemia (CLL). Advantages such as different mechanisms of action (compared with those of chemotherapy), no or minimal stem cell toxicity, as well as the absence of hair loss and delayed nausea may result in a rapidly increasing usage of these agents in different phases of the disease. The combination of moAbs with chemotheraputic agents has shown promising results in early studies as well as their role in the eradication of minimal residual disease (MRD). The availability of an increasing number of new moAbs together with a better understanding of their effector function will hopefully lead to improved therapeutic outcomes for patients with CLL and related disorders.     

Coincidence of B-cell chronic lymphocytic leukemia and cutaneous T-cell lymphoma (mycosis fungoides): immunologic characterization by monoclonal antibodies

Although rare cases of chronic lymphocytic leukemia (CLL) of the T-cell type have been reported, CLL is more commonly found to be a neoplastic lymphoproliferative disease of B-cell origin. In this article, we describe a patient with long-standing CLL that was immunologically shown to be of the B-cell type, who, during the course of his disease, developed cutaneous T-cell lymphoma (CTCL), which was shown to be of the helper/inducer subtype. The neoplastic lymphoid cells in the skin infiltrate differed morphologically and immunologically from those in the peripheral blood. The occurrence of CTCL during this patient's clinical course represents a second neoplasm arising from a different cell line, rather than a tissue manifestation of the patient's CLL. To our knowledge, this is the first report in which the occurrence of CTCL is documented in a patient with immunologically known B-cell CLL. In addition to establishing the presence of B-cell CLL and CTCL of the helper/inducer T-cell type in the same patient, this case report demonstrates the usefulness and necessity of evaluating lymphoproliferative disorders by means of a multidisciplinary approach.     

Adult acute lymphoblastic leukemia phenotypes defined by monoclonal antibodies

Pretreatment peripheral blood and/or bone marrow blasts from 90 adults with acute lymphoblastic leukemia (ALL) were analyzed as part of a prospective treatment protocol study. Specimens were tested by immunofluorescence cytofluorometry for reactivity with the following monoclonal antibodies (MoAbs): BA-1 (B cell antigen); T101, OKT11 (pan-T cell antigens [T]); 3A1 (T cell antigen); MCS-2 (myeloid antigen); J5 common ALL antigen (CALLA); BA4 (Ia antigen [Ia]); BA-2 (lymphohematopoietic antigen). Four major phenotypic groups were identified: B lineage ALL (BA-1+T-) (64%), T lineage ALL (T+BA-1-MCS-2-) (13%), unclassified ALL (BA-1-MCS-2-CALLA-T-) (9%) and myeloid antigen ALL (MCS-2+CALLA-T-) (7%). An additional group of patients, miscellaneous ALL (7%), was comprised of cases with unusual marker profiles. In B lineage ALL, all cases tested were Ia+MCS-2-, and the vast majority were CALLA+ (84%). In T lineage ALL, 42% expressed CALLA or Ia positivity. In unclassified ALL, the predominant phenotype was Ia+BA-2+. In myeloid antigen ALL, two of four tested were 3A1+ and all cases evaluated were BA-1-. Patients with myeloid antigen ALL were older (median age, 66 years) than patients in the other groups. The T lineage ALL group had higher leukocyte counts (median WBCs, 183,000/microL) and an increased incidence of anterior mediastinal mass at presentation. All patients received identical induction therapy. In CALLA+B lineage ALL, 30 of 46 (65%) achieved a complete remission. While the number of patients evaluated was small, 9 of 9 CALLA-B-lineage ALL and only two of six myeloid antigen ALL cases responded with a complete remission. The data suggest that these MoAbs are useful in the characterization of adult ALL.     

Phenotypic heterogeneity of erythroblasts in erythroblastic leukemia revealed by monoclonal antibodies

Eight cases each of erythroleukemia (AML-M6) and erythroblastic crisis of chronic granulocytic leukemia (CGLBC-E) were immunophenotyped with the help of a panel of lineage-associated monoclonal antibodies (McAbs). The latter included those reactive with erythroid progenitor (BFU-E and CFU-E) and erythroid precursors at different stages of maturation. In six of eight cases of AML-M6, erythroblasts revealed an immature phenotype, as evident from reactivity of the blast cells with McAbs directed against the earlier stages of erythroid maturation. One case had the phenotype of CFU-E, and in the remaining case of AML-M6 the erythroblasts showed a "mature" surface antigenic profile. This immunophenotypic spectrum was unrelated to the morphologic maturity of the erythroblasts. In two cases of CGLBC-E, an early erythroblastic phenotype was observed, while in as many cases a "mature" phenotype was present. Four of eight cases, however, revealed a mixed, erythroid plus myeloid phenotype. In one of the four cases, two separate blast populations, which represented erythroblasts and myeloblasts, could be identified. In the remaining three cases the blasts were morphologically homogeneous and undifferentiated. High incidence of HLA-DR positivity in the latter three cases suggests the primitive nature of blasts cells and their closeness to the putative "bipotent" myeloid stem cell. Our study has shown phenotypic heterogeneity of blast cells in AML-M6 and CGLBC-E.     

Immunodiagnosis of chronic lymphatic leukemia and leukemic non-Hodgkin's lymphoma with the monoclonal antibodies BL-Ig-L/1, BL-DR/1 and BL-T2

3 self made monoclonal antibodies are tested with the indirect immunofluorescence method for the immunologic diagnostic of the circulating lymphocytes from 24 chronic lymphatic leukaemia (CLL) and 14 leukaemic Non-Hodgkin lymphoma (NHL) patients. In comparison, investigations were done with various specific rabbit antibody F(ab)2 fragments and antisera. The monoclonal antibody BL-Ig-L/1, which is directed to the human Ig L-chains, marked the neoplastic lymphocytes from 12 of 24 CLL and from 9 of 14 leukaemic NHL as membrane Ig+. The monoclonal antibody BL-DR/1, which reacts with a HLA-DR, binds to the blood lymphocytes of 23 CLL and 11 NHL patients. By this BL-DR/1 is superior to BL-Ig-L/1 for the immunologic diagnostic of the non-T-cell neoplasia. The with normal peripheral T-cells reactive monoclonal antibody BL-T2 reacts with malignant B lymphocytes on an equal scale as BL-DR/1. It is not qualified for the differentiation of malignant blood lymphocytes.     

Autologous bone marrow transplantation in acute myelogenous leukemia: in vitro treatment with myeloid cell-specific monoclonal antibodies

Second or third chemotherapy-induced remissions in acute myelogenous leukemia (AML) are limited by early relapse of the leukemia. We developed monoclonal antibodies (MoAbs) that are cytotoxic to myeloid leukemia cells to treat bone marrow from these patients ex vivo for autologous transplantation. In this pilot study, bone marrow was harvested from ten patients with AML in remission, treated with one or two complement-fixing MoAbs, PM-81 and AML-2-23, which react with myeloid differentiation antigens, incubated with rabbit complement, and cryopreserved. These MoAbs were chosen because they have broad reactivity with AML cells but not with pluripotent progenitor cells. At the time of transplant, 6 patients were in second complete remission, 1 each was in third complete or partial remission, and 2 were in early first relapse. The patients were treated with cyclophosphamide (60 mg/kg a day for 2 days) and total body irradiation (200 cGy twice a day for 3 days) and given infusions of MoAb-treated bone marrow. Full bone marrow reconstitution was observed in eight patients; two patients did not recover platelets. Seven of the ten patients are surviving and disease-free at 21.0, 15.0, 13.0, 10.0, 6.0, 3.0, and 2.0 months posttransplant. Treating bone marrow with MoAbs to myeloid differentiation antigens does not interfere with pluripotential stem cell engraftment. Longer follow-up and a controlled study are necessary to prove that the apparent efficacy of this therapeutic approach in some patients is attributable to MoAb-mediated killing of leukemia cells.     

Autologous bone marrow transplantation in non-Hodgkin's lymphoma: monoclonal antibodies plus complement for ex vivo marrow treatment

PURPOSE: Patients with non-Hodgkin's lymphoma who fail to achieve a complete remission or who relapse are rarely cured with conventional therapies. For this group of patients, intensive therapy and bone marrow rescue may be curative. Our goal was to assess the effects of autologous transplantation in patients with B-cell lymphomas and a poor prognosis. To avoid occult or overt contamination with lymphoma, monoclonal antibodies BA-1, BA-2, and BA-3 were used for ex vivo marrow treatment. PATIENTS AND METHODS: Seventeen patients underwent intensive therapy and autologous bone marrow transplant using the aforementioned marrow. Ten of the 17 patients (Group I) had disease that was in complete or partial remission. The other seven patients either had disease that was not responsive to treatment or had bone marrow transplant as their initial therapy at relapse. RESULTS: The ex vivo treatment did not adversely affect engraftment. For those patients who could be evaluated, the median time to white cell engraftment was 24 days; the median durations of red cell and platelet support were 24 and 29 days, respectively. Eleven of the 17 patients had complete remissions at the evaluation 28 days after transplant. Three patients subsequently experienced a relapse, three died while their disease was in complete remission, and five are alive and disease-free 405 to 1,674 days after transplant. Group I patients had an estimated 40 percent disease-free survival rate at three years compared with 0 percent for Group II patients (p less than 0.01). CONCLUSION: Our data support autologous bone marrow transplantation as an important treatment modality for the non-Hodgkin's lymphomas. With the current preparative regimens available, however, its use should be limited to patients with disease that is still responding to conventional therapies.     

Subpopulation heterogeneity in human acute myeloid leukemia determined by monoclonal antibodies

The leukemic population in 63 patients with acute myeloid leukemia (AML) was studied with 15 monoclonal antibodies that detect lineage-related and stage-related antigens on normal hemopoietic cells. Indirect immunofluorescence and fluorescence-activated cell sorting showed that subpopulations of leukemic cells reacted with some or all antibodies, but the percentage of cells reacting with a single antibody varied widely among patients. The composite antigenic phenotype of the various cases, as determined by immunofluorescence assay, did not correlate with the French-American-British morphological classification. Furthermore, some cells in each case failed to express any antigen normally expressed on myelomonocytic precursors from the level of the early CFU-GM to the mature granulocyte or monocyte. In double-fluorescence experiments, the individual cells expressed none, one, or both antigens. These results demonstrate that there is considerable subpopulation heterogeneity in AML. This heterogeneity may considerably limit or complicate the use of monoclonal antibodies for diagnosis, prognosis, and treatment of acute nonlymphocytic leukemia (ANLL).