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M Pfreundschuh

Publications and source records attributed to M Pfreundschuh.

At least 37 records · Page 2Linked to original sources
PubMed2001

Anti-CD16/CD30 bispecific antibody treatment for Hodgkin's disease: role of infusion schedule and costimulation with cytokines.

The natural killer cell-activating anti-CD16/CD30 bispecific monoclonal antibody (BiMAb) had shown efficacy in a Phase I/II trial of refractory Hodgkin's disease (HD). To gain additional information on clinical efficacy and to investigate the effects of different application schedules and the concomitant application of cytokines, we performed a second randomized pilot trial using this BiMAb in patients with refractory HD. Patients received 4 x 25 mg HRS-3/A9 either as a continuous infusion for 4 days or as a 1-h infusion every other day. In case of an objective response, retreatment was attempted after 4 weeks; in case of stable disease (SD), a second course was given after prestimulation with interleukin 2 and followed by granulocyte macrophage colony-stimulating factor s.c. A total of 16 heavily pretreated patients received one to four BiMAb courses. Overall, we observed one complete remission and three partial remissions lasting 5-9 months (three of four of these responses occurred after continuous BiMAb infusion) and four cases of SD for 3 to >6 months. Interleukin 2 pretreatment before the second BiMAb course resulted in a significant increase of circulating natural killer cells in all five patients treated. This coincided with the conversion of two cases of SD into one complete remission and one partial remission. HRS-3/A9-related side effects consisted of mild fever in only six patients. In summary, this second trial confirmed the antitumor efficacy of this BiMAb against HD and the minor toxicity of this BiMAb. Coadministration of cytokines might contribute to an augmented antitumor activity, and additional clinical trials are warranted to optimize this novel treatment modality.

Adult↗
PubMed2000

Genomic imbalances including amplification of the tyrosine kinase gene JAK2 in CD30+ Hodgkin cells.

Comparative genomic hybridization was applied for a comprehensive screening of frequently occurring net gains and losses of chromosomal subregions in small populations of CD30+ Hodgkin cells and their morphological variants. In 12 Hodgkin's lymphomas, recurrent gains were detected on chromosomal arms 2p, 9p, and 12q (in six, four, and five tumors, respectively) and distinct high-level amplifications were identified on chromosomal bands 4p16, 4q23-q24, and 9p23-p24. In Hodgkin cells with 9p23-p24 amplification, fluorescence in situ hybridization revealed an increased copy number of chromosomal sequences spanning the tyrosine kinase gene JAK2. Several of the imbalances described, in particular a gain in chromosomal arm 9p that includes JAK2 amplification, are similar to the genomic changes detected in primary mediastinal B-cell lymphoma.

Adolescent↗
PubMed2000

[The time factor in oncology: does the overall treatment time in chemotherapy have a role?].

BACKGROUND: The treatment of malignant tumors consists in the optimal combination of the 4 modalities surgery, radiotherapy, chemotherapy, and immunotherapy. An important goal of clinical research is the development of the optimal application of each of these modalities. METHOD: This review of the literature focuses on the importance of the total treatment duration and dose intensity in the development of chemotherapy regimens. Three important malignant diseases will be examined as to the optimal application of systemic chemotherapy. RESULT AND CONCLUSION: Tumor models with the resulting hypotheses and well-designed clinical trials will lead to progress in the treatment of malignant tumors.

Acute Disease↗
PubMed2000

Exploitation of the B cell repertoire for the identification of human tumor antigens.

The screening of tumor-derived expression libraries for antigens that are detected by high-titer immunoglobulin G antibodies from the sera of patients with cancer using serological identification of antigens by recombinant expression cloning (SEREX) allows for the systematic search for antigens of human cancers. SEREX has led to the identification of a plentitude of new tumor antigens in many different tumor entities. These antigens, many of which are encoded by hitherto unknown genes, can be grouped into different classes. Serologically defined human tumor antigens facilitate the identification of antigenic peptides recognized by tumor-specific T lymphocytes, thus providing a molecular basis for polyvalent peptide-based and gene therapeutic vaccine strategies in a wide variety of human neoplasms. Finally, many of the antigens identified using SEREX seem to play a functional role in the pathogenesis of malignant disease.

Antibodies, Neoplasm↗
PubMed2000

Immune recruitment by bispecific antibodies for the treatment of Hodgkin disease.

For the treatment of Hodgkin lymphoma, bispecific monoclonal antibodies (bi-mAbs) were established which recognize the Hodgkin-associated CD30 antigen with one arm and the CD3 or CD28 antigen on T lymphocytes or the CD16 antigen on natural killer (NK) cells with the second arm. The NK cell-activating alpha-CD16/CD30 antibody was able to retarget human NK cells toward CD30- target cells and induce their lysis. Sixty percent of Hodgkin tumor-bearing severe combined immunodeficient mice responded to a combined treatment with bi-mAb and human NK cells, leading to a final cure rate of 20%. T cell-activating bi-mAbs were more effective, resulting in the cure of all mice treated. The in vivo administration of both alpha-CD3/CD30 and alpha-CD28/CD30 antibodies resulted in the specific activation of resting human T cells infiltrating the CD30+ Hodgkin tumors. Tumor-infiltrating lymphocytes in the group of mice treated with both T cell-activating bi-mAbs expressed high levels of cytokines and cytotoxic molecules such as perforin and the cytotoxic serine esterases granzyme A and B. More importantly, activated T cells did not home to CD30 tissue and did not enter the circulation. Encouraged by these preclinical data, 15 patients with treatment-refractory Hodgkin lymphoma were included in a phase I/II dose-escalation study and treated four times every 3 or 4 days with increasing doses of the alpha-CD16/CD30 bi-mAb ranging from 1 mg/m2 to 128 mg/m2. No dose-limiting toxicity occurred even at the highest doses. Of these 15 patients, one had a complete response, one a partial response, three a mixed response, two stable disease, and eight patients had progressive disease. Treatment with immunological effector cell-recruiting bi-mAbs is a promising new approach to the treatment of Hodgkin disease refractory to standard therapy.

Animals↗
PubMed2000

Initiation of humoral and cellular immune responses in patients with refractory Hodgkin's disease by treatment with an anti-CD16/CD30 bispecific antibody.

Fifteen patients with refractory Hodgkin's disease were treated in a dose-escalation trial with the bispecific monoclonal antibody (bi-mAb) HRS-3/A9, which is directed against the Fc gamma receptor III (CD16 antigen) and the Hodgkin's-associated CD30 antigen. Treatment consisted of four cycles of four bi-mAb infusions given over 1 h every 3-4 days at different dose levels ranging from 1 mg/m2 to 64 mg/m2. Measurable serum levels (above 0.1 microgram/ml) of circulating bi-mAb could be detected in patients treated with doses above 4 mg/m2, reaching peak levels of 9.5 micrograms/ml immediately after the end of antibody infusion on the highest dose level. Bi-mAb elimination corresponded to second-order kinetics with a terminal half-life time (t1/2, beta) of 28-32 h. Bi-mAb treatment induced the occurrence of human anti-(mouse Ig) antibodies (HAMA) in 6 out of 13 patients initially testing negative. All 6 patients not only developed anti-isotypic anti-(mouse Ig) but also anti-idiotypic and anti-anti-idiotypic antibodies. While no consistent changes of peripheral blood cell counts, or of any lymphocyte subpopulation including natural killer (NK) cells, has been observed, 4 out of 6 evaluable patients treated with doses of at least 4 mg/m2 showed an increase of NK cell activity within 2 weeks after treatment, which lasted for a maximum of 12 weeks. Circulating amounts of soluble CD30 antigen could be detected in the serum of 6 patients. However, like the results and time courses of all the other immunological parameters evaluated, this was not predictive for treatment outcome.

Animals↗
PubMed2000

Tumour vaccines: a new immunotherapeutic approach in oncology.

Substantial progress has been made in vaccine development in recent years for the treatment of malignant diseases. New technologies have fostered the identification of potentially immunogenic tumour antigens that can be used to activate the patient's immune system to specifically recognize and destroy human tumour cells. More detailed insights into the process of intracellular protein degradation, processing and cell surface presentation have allowed immunogenic peptide domains to be identified that can be used in vaccine trials. Still a matter of intensive debate is the question of the most optimal presentation of tumour-derived proteins or peptides to the immune system to achieve a maximum response. In this area, major progress has been made by using dendritic cell or even naked DNA-based vaccines. The generation of new tools such as HLA-tetramer complexes now allows researchers to monitor more closely the expansion of peptide-specific T cells under the process of vaccination. On the basis of these advances, a couple of vaccine trials have been performed that have increased our knowledge of vaccine development and provided indications that the concept of tumour-specific vaccination might be valid. However, we are still at the beginning of this process and should always remember that only well-designed, prospective clinical trials can define the optimal use of tumour vaccines in oncology.

Cancer Vaccines↗
PubMed2000

Gene-modified spontaneous Epstein-Barr virus-transformed lymphoblastoid cell lines as autologous cancer vaccines: mutated p21 ras oncogene as a model.

The transfer of genes coding for tumor antigens (Ags) into Ag-presenting cells is a promising strategy to develop cancer vaccines for patients not limited by major histocompatibility complex restriction. To test whether autologous lymphoblastoid cell lines (LCL) can be used as an alternative to dendritic cells for Ag presentation, we established LCL by spontaneous growth in cyclosporin-containing medium in vitro (SP-LCL). SP-LCL, which have an advantage over B95-8-transfected LCL in that they carry no risk of introducing a new infectious agent when used for vaccination, served as a permanent source for transfection with an episomal Epstein-Barr virus-based expression vector encoding the Ki-ras p21 oncogene carrying a point mutation at codon 12 (muRas) as a model tumor Ag. The ability of muRas-transfected SP-LCL (muRas-LCL) to induce immunoreactivity was determined in vitro. After electroporation with an optimized protocol, muRas-LCL expressed mutated ras peptides for a considerable period of time (at least 8 weeks) on the cell surface. The transfection procedure did not affect the expression of the costimulatory molecules B7.1, intercellular adhesion molecule-1, and leukocyte function associated Ag-3 by SP-LCL. muRas-LCL were able to induce muRas-specific cytotoxic T lymphocytes from three of three healthy donors and one of one patient with pancreatic carcinoma. Our results suggest that the gene transfer of muRas sequences to SP-LCL leads to an endogenous processing of this Ag in the major histocompatibility complex class I pathway and to functional presentation of antigenic peptides to CD8+ T lymphocytes. Autologous SP-LCL can serve as an unlimited renewable source for autologous cellular vaccines and appear to be good candidates as presenters for a wide range of human tumor Ags.

B7-1 Antigen↗
PubMed2000

Definition of tumor-associated antigens in hepatocellular carcinoma.

With an estimated annual incidence of about one million cases, hepatocellular carcinoma (HCC) is one of the most common neoplasms worldwide. Of all malignant diseases, it is the major cause of death in some regions of Africa and Asia. The pathogenic mechanisms responsible for HCC are not well defined, and therapeutic means, especially in inoperable HCCs, are still unsatisfactory and await improvement. In the quest for tumor antigens exploitable for gene therapy, we studied immune responses in the context of HCC. A cDNA library derived from a human HCC sample was screened using the SEREX approach. Nineteen distinct antigens reactive with autologous IgG were identified. Sequence analysis revealed three of the cDNA clones to code for hitherto unknown proteins and 16 known genes products. Proteins as diverse in function as LDH, albumin, and kinectin were found. Furthermore, proteins involved in the transcription/translation machinery had elicited an immune response in the autologous host. A panel of allogenic sera including sera from patients with hepatitis, liver cirrhosis, HCC, and other tumor entities, as well as sera from normal individuals, was used for frequency analysis of antibody responses. Whereas allogenic sera of HCC patients detected most antigens at a high percentage, control sera were rarely antibody-positive. The nature of the major fraction of antigens described here are linked to liver. Thus, our findings demonstrate not only the complexity of the humoral immune response against HCC, but may also offer new insight into mechanisms underlying transformation of the liver cell.

Adult↗
PubMed2000

Expression of cancer testis genes in human brain tumors.

Cancer-testis (CT) genes are expressed in a variety of human cancers but not in normal tissues, except for testis tissue, and represent promising targets for immunotherapeutic and gene therapeutic approaches. Because little is known about their composite expression in human brain tumors, we investigated the expression of seven CT genes (MAGE-3, NY-ESO-1, HOM-MEL-40/SSX-2, SSX-1, SSX-4,HOM-TES-14/SCP-1, and HOM-TES-85) in 88 human brain tumor specimens. Meningiomas expressed only HOM-TES-14/SCP-1 (18% of meningiomas were HOM-TES-14/SCP-1 positive) and did not express any other CT genes. One ependymoma was negative for all CT genes tested. SSX-4 was the only CT gene expressed in oligodendrogliomas (2 of 5 cases), and it was also expressed in oligoastrocytomas (3 of 4 cases) and astrocytomas (10 of 37 cases). Astrocytomas were most frequently positive for HOM-TES-14/SCP-1 (40%) and SSX-4 (27%), followed by HOM-TES-85 (13%), SSX-2 (11%), and MAGE-3 (7%). Whereas MAGE-3 was detected only in grade IV astrocytomas, the expression of the other CT genes showed no clear correlation with histological grade. Of 39 astrocytomas, 60% expressed at least one CT gene, 21% expressed two CT genes, and 8% coexpressed three CT genes of the seven CT genes investigated. We conclude that a majority of oligoastrocytomas and astrocytomas might be amenable to specific immunotherapeutic interventions. However, the identification of additional tu-mor-specific antigens with a frequent expression in gliomas is warranted to allow for the development of widely applicable polyvalent glioma vaccines.

Antigens, Neoplasm↗
PubMed1999

A bispecific diabody that mediates natural killer cell cytotoxicity against xenotransplantated human Hodgkin's tumors.

CD16/CD30 bispecific monoclonal antibodies can induce remissions of Hodgkin's disease refractory to chemo- and radiotherapy. However, the development of human antimouse immunoglobulin antibodies and allergic reactions precludes repeated applications of the antibody. Moreover, problems of producing and purifying sufficient amounts of material limit the clinical practicability of this novel treatment approach. To overcome these obstacles, we have constructed a bispecific antibody in a diabody form that only employs the variable domains of the CD16/CD30 hybrid hybridoma. The diabody compared favorably with the parent CD16/CD30 bispecific antibody in its ability to activate and target natural killer cells in vitro. Its administration to mice bearing xenografted Hodgkin's lymphoma resulted in a marked regression of tumor growth, thus proving for the first time the capability of a diabody for immune recruitment in vivo. The CD16/CD30 diabody is a novel reagent that should considerably facilitate the immunotherapy of patients with refractory Hodgkin's lymphoma.

Animals↗
PubMed1999

Immunotherapy of human tumors with T-cell-activating bispecific antibodies: stimulation of cytotoxic pathways in vivo.

Bispecific monoclonal antibodies (Bi-mAbs) specific for a tumor-associated antigen and the CD3 or CD28 antigen on T lymphocytes represent one of the most successful experimental strategies for the immunotherapy of cancer. We report that the in vivo administration of both alpha-CD3/CD30 and alpha-CD28/CD30 Bi-mAbs results in the specific activation of xenotransplanted, resting human T cells infiltrating the CD30-positive Hodgkin's tumor. Bi-mAb treatment resulted in enhanced expression of cytokines such as interleukin 1beta, interleukin 2, tumor necrosis factor type alpha, and activation markers including Ki-67, CD25, and CD45RO in tumor-infiltrating lymphocytes. This antigen-dependent, local T-cell stimulation led to the activation of the cytolytic machinery in T lymphocytes, determined by the up-regulation of mRNA-encoding perforin and the cytotoxic serine-esterases granzymes A and B. The Bi-mAb-induced generation of CTLs depended on the presence of the CD30 antigen and the combined application of both Bi-mAbs. Our findings suggest that the combined application of T-cell-activating Bi-mAbs is able to achieve a tumor site-specific activation of the T-cell cytolytic machinery in vivo. The fact that these cytotoxic cells do not home in tumor-associated antigen-negative tissue and do not enter circulation might explain our previous observations (C. Renner et al., Blood, 87: 2930-2937, 1996) of a high cure rate in preclinical models even at an advanced stage of disease.

Animals↗
PubMed1999

EB/RP gene family encodes tubulin binding proteins.

Mutations in the adenomatous polyposis coli (APC) gene are linked to the dysplastic transformation of colorectal polyps and represent an early step in the development of colorectal tumors. Ninety-four percent of all mutations result in the expression of a truncated APC protein lacking the C-terminal region. The C-terminal region of the APC protein may have a tumor suppressor function as its absence appears to be linked to the development of dysplastic lesions. Recently, we discovered and characterized a protein called RP1 which binds specifically to the C-terminal region of the APC protein. We show now that RP1 and the other known members of the EB/RP family (EB1 and RP3) also bind directly to tubulin, both in vitro and in vivo. Immunohistochemical analyses reveal a distinct staining pattern during interphase as well as an association of RP1/EB1 with mitotic microtubule structures. The previously described puncta of the APC protein at the leading edge of membrane protrusions contact microtubule fibers that contain RP1 or EB1.

Adenomatous Polyposis Coli↗
PubMed1999

Enrichment polymerase chain reaction for the detection of Ki-ras mutations: relevance of Taq polymerase error rate, initial DNA copy number, and reaction conditions on the emergence of false-positive mutant bands.

Screening for oncogene mutations as a marker for malignancy can be a powerful tool for the early diagnosis of cancer. The enrichment polymerase chain reaction (PCR) is a sensitive method for the detection of low-frequency mutations in small samples. However, false-positive results, caused by methodological errors, may have severe clinical implications. When applied to the detection of Ki-ras mutations in pancreatic secretions, the assay sensitivity is limited to approximately 1:1400. Our investigation of Ki-ras mutations in blood samples from patients with pancreatic carcinoma revealed PCR bands presumably derived from mutant Ki-ras in samples from healthy volunteers, while all blood samples of the patients with pancreatic carcinomas showed a wild-type band pattern. Mathematical modeling of the PCR reaction reveals that the rate of false positive PCR results depends on the initial amount of DNA, the Taq polymerase error rate, the number of PCR reaction cycles, reaction efficiency and the restriction endonuclease chosen. The overall error rate of false positive results of the enrichment PCR can be reduced to the square of the rate of a single-step analysis if repeated amplifications of the same DNA specimen show an identical result.

False Positive Reactions↗
PubMed1999

Fludarabine and epirubicin in the treatment of chronic lymphocytic leukaemia: a German multicenter phase II study.

PURPOSE: Fludarabine has been reported to be the most effective single-agent in previously treated chronic lymphocytic leukaemia (CLL). Based on the in vitro synergism of fludarabine with anthracyclines and on results showing a higher efficacy of CHOP against COP we attempted to improve treatment results with a combination of fludarabine and an anthracycline. PATIENTS AND METHODS: The aim of the multicenter study was to evaluate the rate and duration of remissions and investigate the toxic and immunosuppressive effects of fludarabine and epirubicin in the treatment of CLL in Binet stages B and C as first-line therapy or in first relapse. Thirty-eight patients were treated with fludarabine 25 mg/m2 on days 1-5 and epirubicin 25 mg/m2 on days 4 and 5. RESULTS: The overall response rate (OR) was 82% (95% confidence interval (95% CI): 66%-92%) with a CR rate of 32% (95% CI: 18%-49%). For the 25 previously untreated patients the OR was 92% (95% CI: 74%-99%) including 40% CRs (95% CI: 21%-61%). Granulocytopenia grade 3 occurred in 23% of all evaluable cycles, and grade 4 in 17%. The median remission duration was 19 months (range 6-37 months). CONCLUSION: The results show that the combination of fludarabine and epirubicin is tolerable and highly effective in the treatment of CLL. With the addition of epirubicin to fludarabine, it appears possible to achieve a higher response rate and a more rapid response, especially of nodal manifestations. This regimen can be administered in an outpatient facility except for the first cycle because of the risk of a tumour lysis. The possible benefit of the combination presented here in the treatment of CLL in comparison to single-agent fludarabine treatment is presently under study in a prospective randomized multicenter study.

Adult↗
PubMed1999

Exploitation of the antibody repertoire of cancer patients for the identification of human tumor antigens.

The screening of tumor-derived expression libraries for antigens which are recognized by high titered IgG antibodies present in autologous sera of the cancer patients by SEREX (serological identification of antigens by recombinant expression cloning) allows for the systematic identification of antigens in human cancers. SEREX has led to the definition of a plentitude of new tumor antigens in many different tumor entities. The majority of the antigens are encoded by hitherto unknown genes and can be grouped into different classes of antigens. The abundance of serologically defined human tumor antigens is not only of relevance for tumor biology and serodiagnosis of cancer, but also facilitates the identification of proteins recognized by tumor specific T lymphocytes, thus providing a molecular basis for polyvalent peptide-based and gene-therapeutic vaccine strategies in a wide variety of human neoplasms.

Antibodies, Neoplasm↗
PubMed1999

The B lymphocyte in rheumatoid arthritis: recirculation of B lymphocytes between different joints and blood.

In order to search for further evidence for a pathogenetic role of recirculating, antigen-driven B cell clones in rheumatoid arthritis (RA) rearranged VH genes were analysed for clonal relationship and somatic mutations from synovial tissue and peripheral blood of a patient with RA undergoing synovectomy of several finger joints. DNA was prepared from the synovial tissue of two finger joints and blood. PCR for the different VH families was performed with one specific oligonucleotide for each VH family and a mixture of JH-specific oligonucleotides. The PCR products were separated on a high resolution acrylamide gel differentiating one base pair difference of length. Transfer of the products onto a nylon membrane and hybridization with an oligonucleotide specific for the FR3 region revealed a polyclonal representation of rearranged VH1, VH3, VH4 and VH5 genes. The VH6 family, which is encoded by a single germline gene, was represented by few distinct bands, with some bands of identical height for both joints and blood. DNA from these bands of interest was eluted, reamplified by PCR, cloned and sequenced. Sequence analysis of 27 independent bacterial colonies allowed distribution of the different VH genes to seven B cell clones (A-G). Members of clone A were found in both joints and blood, clones B and C in one joint and blood, clone D in both joints, and clones E, F and G only in one joint. The VH regions were somatically mutated with characteristic patterns for the different clones. In conclusion, our findings confirm the systemic character of RA, because they show that not only expansion and affinity maturation of B cells occur in synovial membranes but antigen-specific B cells recirculate between different joints and blood.

Adult↗