Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0026986 (myelodysplastic syndrome)
 14,926 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Disease recurrence following successful bone marrow transplantation remains a major impediment in the management of patients with acute myelogenous leukemia (AML) and myelodysplastic syndrome (MDS). A variety of monoclonal antibodies that deliver drugs or toxins to the site of activity, have been used in an attempt to augment marrow transplantation. Examples of three different monoclonal antibody techniques (naked antibody, drug antibody conjugations, and radiolabeled antibodies) are discussed. CD33 is an attractive antigen to use as a target for treating AML because it is present on most AML cells. Naked antibodies are limited in their ability to kill tumor cells, although studies to date suggest there may be a role in antileukemic therapy for unlabeled anti-CD33 humanized M195 antibody after the tumor burden has been reduced by chemotherapy. Calicheamicin, a novel and toxic drug moiety conjugated to anti-CD33 antibody, is currently under investigation in patients with refractory or relapsed AML. Results from a Phase I investigation were encouraging. Three different radiolabeled monoclonal antibodies have been evaluated in Phase I/II studies--131I-labeled anti-CD33 (p67) antibody, 213Bi-labeled humanized M195 antibody, and 131I-anti-CD45 antibody. CD45 is a cell-surface antigen broadly expressed by all circulating leukocytes and lymphocytes. Initial studies demonstrated that substantially greater doses of radiation could be delivered to targeted organs compared with nontargeted organs using 131I-anti-CD45 antibody. This approach offers the potential for augmenting leukemia therapy without increased risk of toxicity.
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PMID:Immunotherapy in acute myelogenous leukemia and myelodysplastic syndrome. 977 93

Mononuclear cells of the bone marrow (BM) of patients in various subgroups of the myelodysplastic syndrome (MDS) were studied by flow cytometry for the expression of myeloid and lymphoid markers both on the surface and in the cytoplasm. A significantly higher percentage of the BM cells of MDS patients reacted with monoclonal antibodies (mAbs) to myeloid antigens (CD13, CD15 and CD33) by cytoplasmic staining as compared with cell surface staining. The percentage of BM cells expressing CD34 was markedly elevated in patients with RAEB-T. A distinct finding in MDS patients was the expression of myeloid antigens on mononuclear BM cells. The proportion of individuals whose mononuclear BM cells were positive for surface reactivity with anti-CD13 and anti-CD33 mAbs was highest among RAEB-T patients while none of the patients with RA expressed these surface antigens. Cytoplasmic staining significantly increased the percentage of CD13+ and CD33+ BM cells among RAEB and RAEB-T patients. The proportion of individuals whose BM cells possessed myeloid antigens was increased by cytoplasmic staining in all subgroups of MDS. The BM of a considerable proportion of RAEB-T and RAEB patients showed cells which coexpressed the CD7 and CD3 lymphoid markers along with the CD13 and CD33 myeloid antigens. The present study indicates the importance of comparative surface and cytoplasmic immunophenotyping with CD13 and CD33 mAbs for the diagnosis of subgroups of MDS. The coexpression of CD3 and CD7 with markers of the myeloid lineage may reflect derangement of the differentiation of pluripotent stem cells characteristic for MDS.
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PMID:Analysis of myeloid and lymphoid markers on the surface and in the cytoplasm of mononuclear bone marrow cells in patients with myelodysplastic syndrome. 981 67

The antigen CD33 is expressed on blast cells in 80% to 90% of acute myeloid leukemia (AML) cases but, importantly, is not expressed on pluripotent hematopoietic stem cells or on nonhematologic cells. Gemtuzumab ozogamicin (CMA-676) uses a recombinant humanized anti-CD33 monoclonal IgG4 antibody to deliver the potent cytotoxin, calicheamicin, into cells. Three multicenter trials have evaluated the efficacy and safety of gemtuzumab ozogamicin as a single agent in 142 patients with CD33+ AML in untreated first relapse. The median age was 61 years (range, 22 to 84 years), none had prior myelodysplasia, and all had had a first complete remission lasting > or = 3 months. Two doses of 9 mg/m2 were given 14 days apart by 2-hour intravenous infusion. The overall response rate was 30% (ie, < or = 5% blasts remaining in the bone marrow, neutrophils > or = 1,500/microL, and red blood cell and platelet transfusion independence). There was no significant difference in response rate between patients less than 60 years of age and those > or = 60 years old (34% v 26%, respectively) or between patients whose first remission had lasted less than 12 months or > or = 12 months (28% v 32%, respectively). Overall survival was 31% at 1 year; median survival was 5.9 months. Median relapse-free survival was 6.8 months. An infusion-related syndrome (chills, fever, rigors, nausea, hypotension, and pain) was common. Severe myelosuppression occurred in all patients, but severe mucositis (4%) and infections (23%) were relatively infrequent. Severe hyperbilirubinemia (23%) and elevated hepatic transaminases (18%) were usually transient. Among all 142 patients, the median total hospitalization was 24 days; 16% of patients required < or = 7 days in hospital. Additional studies are currently evaluating gemtuzumab ozogamicin in combination with, or as an alternative to, other standard AML chemotherapy.
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PMID:Current use and future development of gemtuzumab ozogamicin. 1147 94

Gemtuzumab ozogamicin (Mylotarg) is an immunoconjugate composed of a recombinant humanized murine anti-CD33 antibody linked to calicheamicin, a potent cytotoxic agent. The aim of this review is to summarize ongoing trials with gemtuzumab ozogamicin in combination with chemotherapy in acute myeloid leukemia (AML) patients. The studies include determination of safety and efficacy of gemtuzumab ozogamicin in combination with chemotherapy in previously untreated as well as relapsed and refractory AML patients. These studies also determine gemtuzumab ozogamicin's activity in patients with other CD33+ neoplastic diseases such as myelodysplastic syndrome, acute promyelocytic leukemia, chronic myeloid leukemia, and certain subsets of acute lymphocytic leukemia. Moreover, trials are exploring the use of gemtuzumab ozogamicin with novel targeted agents such as Bcl-2 antisense molecules. Gemtuzumab ozogamicin is associated with an acceptable toxicity profile as a single agent; however, the incidence of veno-occlusive disease remains a concern with the use of gemtuzumab ozogamicin in combination with chemotherapy.
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PMID:Trials with gemtuzumab ozogamicin (Mylotarg) combined with chemotherapy regimens in acute myeloid leukemia. 1197 Jul 67

We measured the concentration of CD33 antigen on the surface of cells in 315 bone marrow (BM) samples and 114 corresponding peripheral blood (PB) samples from patients with various leukemias (acute myeloid leukemia [AML], chronic myelogenous leukemia [CML], myeloproliferative disorder [MPD] other than CML, myelodysplastic syndrome [MDS]) and from control subjects. Overall CD33 intensity in total CD33+ cells was significantly higher in BM than in PB. CD33 intensity in total BM CD33+ cells differed significantly with the type of disease. The median number of CD33 molecules per cell was highest in AML, followed by MDS, CML, and control subjects and lowest in MPD. When only CD34+/CD33+ cells were examined, CD33 molecules per cell were highest in CD34+ cells in AML and lowest in MPD (P = .027). Patients with AML or MDS younger than 60 years had significantly higher intensity of CD33 expression on CD34+ cells than patients 60 years or older. Levels of CD33 intensity did not correlate with cytogenetics in patients with AML or MDS. There was no correlation between CD33 intensity and response to therapy or overall survival in 35 patients treated with protocols including Mylotarg. These data demonstrate variation in CD33 intensity between various leukemias.
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PMID:Differences in CD33 intensity between various myeloid neoplasms. 1237 43

Gemtuzumab ozogamicin (GO), a monoclonal antibody used in the treatment of acute myelogenous leukemia (AML) has been linked to the development of venoocclusive disease (VOD). We conducted a retrospective study of 62 patients with previously treated AML/MDS (myelodysplastic syndrome) who underwent allogeneic stem cell (SC) transplantation at our institution from December 2000 to October 2002 to determine whether GO exposure prior to allogeneic SC transplantation increases the risk of developing VOD. Fourteen patients received GO prior to SC transplantation. Of 62 patients, 13 (21%) developed VOD; 9 (64%) of 14 with prior GO exposure developed VOD compared with 4 (8%) of 48 without prior GO exposure (P <.0001). Logistic regression controlling for sex, disease status, donor type, and graft-versus-host disease prophylaxis identified prior treatment with GO as a significant risk factor for VOD (odds ratio [OR], 21.6; 95% confidence interval [CI], 4.2-112.2]. Nine of 10 patients who underwent SC transplantation 3.5 months or less following GO developed VOD compared with none of 4 patients who underwent SC transplantation more than 3.5 months from GO administration. Three of 14 patients who received GO prior to SC transplantation died of VOD. We conclude that patients undergoing SC transplantation within a short interval from GO administration are at increased risk of developing VOD.
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PMID:Prior gemtuzumab ozogamicin exposure significantly increases the risk of veno-occlusive disease in patients who undergo myeloablative allogeneic stem cell transplantation. 1497 63

In the past three decades, improvements in the treatment of acute myeloid leukemia (AML) have increased survival in patients younger than 55 years without significant survival impact in older individuals. Unfortunately, many patients, regardless of age at diagnosis, will eventually die from their disease. Advances in the development of targeted therapies have proven beneficial in chronic myeloid leukemia and lymphoma. Gemtuzumab ozogamicin (GO; Mylotarg, Wyeth-Ayerst, St Davids, PA), a monoclonal antibody conjugated to calicheamicin, targets the CD33 antigen found on the surface of more than 80% of AML leukemic blasts. GO is approved for relapsed disease in patients older than 60 years, but is being evaluated in combination with chemotherapy, in the setting of hematopoietic stem cell transplant, and in high-risk myelodysplasia.
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PMID:New developments in antibody therapy for acute myeloid leukemia. 1293 19

Recent progress in understanding the pathobiology of the myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML) have led to the development of various immunologically oriented therapies for these diseases. The existence of elevated levels of tumor necrosis factor-alpha (TNF-alpha) in bone marrow during early stages of MDS, and the possibility that TNF- proportional, variant suppresses normal hematopoiesis led to studies of attempts to block the activity of TNF-alpha. An anti-TNF monoclonal antibody and an antibody comprised of the soluble extracellular ligand-binding portion of the TNF receptor have both been evaluated recently in several small pilot studies. The recognition that marrow suppression in MDS may, in part, be a T-cell mediated autoimmune process has stimulated various trials of antithymocyte globulin and other similar agents. Gemtuzumab ozogamicin, an antibody against CD33 conjugated to the cytotoxic agent calicheamicin, is approved for use in AML and is currently being investigated as a potential therapeutic agent in MDS. Clinical trials were conducted as either monotherapy or in combination with cytokines such as IL-11 and chemotherapeutic agents including idarubicin, fludarabine, and/or cytarabine. Other antibodies are being developed as immunoconjugates with radioisotopes as part of conditioning regimens prior to bone marrow transplantation for AML or MDS. These include (131)I-anti-CD45 antibody (BC8), (131)I anti-CD33 antibody (p67), (213)Bi-M195 antibody, and (188)Re-labeled anti-CD66 antibody. The clearest example of successful immunotherapy for MDS (and AML) is the use of the graft-versus-tumor effect associated with allogeneic hematopoietic cell transplantation. Recently, nonmyeloablative transplants have been explored with encouraging results. Vaccines using overexposed self-antigens such as WT1 and PR1 are other attempts to induce a T-cell mediated response against MDS.
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PMID:Immunobiologic therapies for myelodysplastic syndrome. 1549 1

Acute myeloid leukemia (AML) has a poor prognosis due to treatment-resistant relapses. A humanized anti-CD33 antibody (Mylotarg) showed a limited response rate in relapsed AML. To discover novel AML antibody targets, we selected a panel of single chain Fv fragments using phage display technology combined with flow cytometry on AML tumor samples. One selected single chain Fv fragment broadly reacted with AML samples and with myeloid cell lineages within peripheral blood. Expression cloning identified the antigen recognized as C-type lectin-like molecule-1 (CLL-1), a previously undescribed transmembrane glycoprotein. CLL-1 expression was analyzed with a human anti-CLL-1 antibody that was generated from the single chain Fv fragment. CLL-1 is restricted to the hematopoietic lineage, in particular to myeloid cells present in peripheral blood and bone marrow. CLL-1 is absent on uncommitted CD34(+)/CD38(-) or CD34(+)/CD33(-) stem cells and present on subsets of CD34(+)/CD38(+) or CD34(+)/CD33(+) progenitor cells. CLL-1 is not expressed in any other tissue. In contrast, analysis of primary AMLs demonstrated CLL-1 expression in 92% (68 of 74) of the samples. As an AML marker, CLL-1 was able to complement CD33, because 67% (8 of 12) of the CD33(-) AMLs expressed CLL-1. CLL-1 showed variable expression (10-60%) in CD34(+) cells in chronic myelogenous leukemia and myelodysplastic syndrome but was absent in 12 of 13 cases of acute lymphoblastic leukemia. The AML reactivity combined with the restricted expression on normal cells identifies CLL-1 as a novel potential target for AML treatment.
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PMID:C-type lectin-like molecule-1: a novel myeloid cell surface marker associated with acute myeloid leukemia. 1554 16

Advances in the development of monoclonal antibody (MAb) have proven major benefice in the treatment of hematologic malignancies. Phase II studies showed similar results than classical chemotherapy in refractory or relapsed patients, with less toxicity in heavily pre-treated population. Moreover, MAb enhanced sensitivity to chemotherapy. Combined treatments resulted in an increase of global response and complete remission in non previously pre-treated patients with follicular lymphoma, diffuse large cell lymphoma and chronic lymphocytic leukemia. Recently, the association of anti-CD20 and 131Iode was shown to be efficient in follicular lymphomas. The benefits of MAb is less clear in myeloid malignancies. The role of MAb in the treatment of myelodysplastic syndrome remains uncertain although the use of anti-CD33 in acute myeloid leukemias is promising. The aim of this review is to present an updated overview of the most used MAb in the treatment of leukemias and lymphomas not involving bone marrow transplantation.
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PMID:[Monoclonal antibodies for lymphomas and leukemias in 2005]. 1645 13


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