Seminars in hematology
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Seminars in hematology · Jul 2001
ReviewCurrent use and future development of gemtuzumab ozogamicin.
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. ⋯ 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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Anemia is a common clinical problem in critically ill patients and is associated with substantial red blood cell (RBC) transfusion requirements. However, RBC transfusion has significant risks, including adverse effects on the immune system. Although a low hemoglobin concentration may be tolerable, it may not be optimal for the critically ill patient. ⋯ Results of a recent randomized controlled trial in critically ill patients demonstrated that recombinant human erythropoietin (r-HuEPO, epoetin alfa) significantly reduced (by approximately 50%) the number of RBC units transfused (P <.002) and significantly increased hematocrit (P <.01) compared with placebo. There was no increase in mortality or adverse clinical events with therapy. Epoetin alfa may be an effective therapeutic approach to anemia in critically ill patients, decreasing the need for transfusion and achieving higher hemoglobin concentrations than generally attained with transfusion.
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The expanding indications for transfusions in patients with sickle cell disease raise the issues of appropriate measurement of body iron burden and optimal timing of iron chelation therapy. In this study, we obtained 42 biopsy specimens from 20 patients with sickle cell disease (mean age, 15.7 years) who received transfusions. In 12 patients whose mean age was 11.3 years at the time of liver biopsy, hepatic iron concentration was measured to provide information about the rate of iron accumulation in sickle cell disease, as well as to guide the initiation of chelating therapy. ⋯ These data show that after 1 to 2 years of conventional transfusions, variable tissue iron concentrations and tissue damage are observed in patients with sickle cell disease. In some patients, iron chelation therapy may not be appropriate after 1 year of transfusions; in others, therapy is clearly indicated by this time to prevent tissue injury. The data also suggest that patients with sickle cell disease develop increased portal fibrosis at the thresholds previously described in young patients with thalassemia (approximately 7 mg/g of liver, dry weight).
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Myeloproliferative diseases (MPD) include polycythemia vera (PV), essential thrombocythemia, agnogenic myeloid metaplasia, and chronic myelogenous leukemia. The focus of this report is on PV, which is characterized by an increase in red blood cells, granulocytes, and platelets. Complications associated with PV are an increased risk of thrombosis and abnormal bleeding. ⋯ It is clear that no single agent satisfies all the needs for cytoreduction that arise during the course of PV. Future protocols should be designed that draw on the large body of experience already gained with these drugs to transcend the limitations of single-agent therapy and to improve quality of life as well as survival. Semin Hematol 38(suppl 2):25-28.