Doripenem versus meropenem as first-line empiric therapy of febrile neutropenia in patients with acute leukemia: a prospective, randomized study.

Febrile neutropenia is often observed in patients with hematologic malignancies, especially in those with acute leukemia. Meropenem has potent and broad antibacterial activity against gram-positive and gram-negative bacteria, and is recommended as first-line empiric therapy for febrile neutropenia. In contrast, the safety and efficacy of doripenem in patients with febrile neutropenia and hematologic malignancies is limited. In this randomized, prospective, cooperative, open-label trial, we compared doripenem (1.0 g every 8 h) to meropenem (1.0 g every 8 h) as first-line empiric antibacterial treatment of febrile neutropenia. To evaluate efficacy and safety, 133 hospitalized patients with acute leukemia or high-risk myelodysplastic syndrome, who developed febrile neutropenia during or after chemotherapy, were randomized to each drug. Resolution of fever within 3 to 5 days without treatment modification (i.e., the primary endpoint) did not significantly differ between the doripenem and meropenem groups (60.0% vs. 45.6%, respectively; P = 0.136). However, resolution of fever within 7 days of treatment was significantly higher in the doripenem group than in the meropenem group (78.4% vs. 60.2%, respectively; P = 0.037). Similar rates of adverse events (grades 1-2) were observed in both groups. Thus, we conclude that both drugs are safe and well-tolerated for the treatment of febrile neutropenia in patients with acute leukemia or high-risk myelodysplastic syndrome, and that the clinical efficacy of doripenem is noninferior to that of meropenem. UMIN Clinical Trial Registry number: 000006124.

Clinical significance of high-Km 5'-nucleotidase (cN-II) mRNA expression in high-risk myelodysplastic syndrome.

We analyzed cytosolic high-Km 5'-nucleotidase (cN-II) and deoxycytidine kinase (dCK) mRNA expression in bone marrow mononuclear cells (BMMNC) of patients with high-risk myelodysplastic syndrome (MDS) using quantitative real-time polymerase chain reaction (rt-PCR). At diagnosis, the cN-II mRNA expression of patients was higher than that of healthy volunteers, but the dCK mRNA expression showed no significant difference. Patients with ara-C-containing chemotherapies whose BMMNC showed a high level of cN-II expression (greater than the median value) had shorter median overall survival (15 months versus 22 months, p<0.01) and shorter median post-chemotherapy survival (10 months versus 16 months, p=0.012). These data suggest that the expression level of cN-II mRNA might be a prognostic factor of high-risk MDS.

Clinical and biological significance of CD56 antigen expression in acute promyelocytic leukemia.

The biological significance of CD56 antigen expression in patients with acute promyelocytic leukemia (APL) has been under investigation. We investigated the clinical and biologic features of CD56+APL. In our series, CD56 antigen was positive in 4 of 28 (14%) APL patients. No differences were found regarding age, gender, performance status (PS), initial leukocyte and platelet counts, lactate dehydrogenase (LDH) and fibrinogen (Fbg) levels according to CD56 expression. CD34 antigen was co-expressed in 3 of the 4 patients with CD56+ APL, in contrast to 2 of the 24 patients with CD56- APL (P = .01). Extramedullary relapse occurred in 3 of the 4 patients with CD56+ APL, in contrast to none of the 24 patients with CD56- APL (P = .001). Median remission duration was 4 months in CD56+ APL and was not reached in CD56- APL. The CD56+ population had a shorter remission duration (P < .0001) and disease-free survival (P < .0001). In contrast, no difference was found in overall survival. These results suggested that CD56 expression was associated with the leukemogenetic mutation at the primitive hematopoietic progenitor cell level and extramedullary relapse in APL patients treated with ATRA and chemotherapy.

Distinguishing between proliferating nodal lymphoid blasts in chronic myelogenous leukemia and non-Hodgkin lymphoma: report of three cases and detection of a bcr/abl fusion signal by single-cell analysis.

Lymph node biopsies were analyzed from three patients with chronic myelogenous leukemia (CML) showing nodal blast proliferation. Immunohistochemically, the blasts from all three patients had an immature marker profile with a T-blast population (cCD3+, CD4-, CD7+, CD8-, CD99+, terminal deoxynucleotidyl transferase +) and a hematopoietic progenitor cell marker (CD34). In two patients, the blasts also expressed myeloid lineage specificity (naphthol AS-D chloroacetate esterase activity and myeloperoxidase positivity). However, it was difficult to distinguish between blast proliferation in CML and non-Hodgkin lymphoma from these immunohistopathological findings alone. Subsequently, bcr gene rearrangement and bcr/abl mRNA expression were detected by Southern blot and reverse transcription-polymerase chain reaction analysis of the lymph nodes. Fluorescence in situ hybridization (FISH) analysis of lymph node touch smears also disclosed bcr/abl gene fusion signals in the blasts of all patients, confirming that the blasts were derived from Philadelphia chromosome-positive CML. Accurate discrimination between the proliferating nodal blasts of CML and non-Hodgkin lymphoma is essential for determining subsequent therapy. FISH analysis of bcr/abl in single-cell blast preparations is an efficient tool that allows rapid, accurate cytopathological diagnosis of extramedullary blast-phase CML and its discrimination from non-Hodgkin lymphoma.