Phase 2 study of arsenic trioxide followed by autologous hematopoietic cell transplantation for relapsed acute promyelocytic leukemia.

The optimal treatments for relapsed acute promyelocytic leukemia (APL) remain equivocal. We conducted a phase 2 study to evaluate the efficacy and feasibility of a sequential treatment consisting of induction and consolidation with arsenic trioxide (ATO), peripheral blood stem cell (PBSC) harvest after high-dose cytarabine chemotherapy, and autologous hematopoietic cell transplantation (HCT). Between 2005 and 2009, 35 patients (26 with hematologic and 9 with molecular relapse) were enrolled. Induction therapy resulted in complete remission in 81% of those with hematologic relapse, and most patients became negative for PML-RARα after the first ATO consolidation course, but 4 remained positive. Administration of the second ATO consolidation course further decreased the transcript levels in 3 patients. In total, 25 patients proceeded to PBSC harvest, all of whom successfully achieved the target CD34+ cell doses, and 23 underwent autologous HCT with PML-RARα-negative PBSC graft. Posttransplant relapse occurred in 3 patients, and there was no transplant-related mortality. With a median follow-up of 4.9 years, the 5-year event-free and overall survival rates were 65% and 77%, respectively. These findings demonstrate the outstanding efficacy and feasibility of the sequential treatment featuring ATO and autologous HCT for relapsed APL. This study was registered at http://www.umin.ac.jp/ctr/ as #C000000302.

Optimized dosage and frequency of cefozopran for patients with febrile neutropenia based on population pharmacokinetic and pharmacodynamic analysis.

OBJECTIVES: To establish a cefozopran (a fourth-generation cephem) population pharmacokinetic model using patient data and use it to explore alternative dosage regimens that could optimize the currently used dosing regimen to achieve higher likelihood of pharmacodynamic exposure against pathogenic bacteria. METHODS: We conducted a prospective clinical trial of cefozopran for haematological patients with febrile neutropenia (FN). Twenty-two patients (30 episodes) were selected to receive intravenous cefozopran every 8 h on a daily basis. We gathered concentration data and performed the NONMEM program. The Monte Carlo simulation was performed to assess the pharmacodynamic exposure based on the population pharmacokinetics and MIC. RESULTS: The NONMEM program demonstrated that a two-compartment model provided a best fit for the data, that is, CL of 4.62 (L/h), V1 of 10.3 (L), Q of 4.47 (L/h), and V2 of 4.48 (L). On the basis of the Japanese national surveillance findings for Pseudomonas aeruginosa, methicillin-sensitive Staphylococcus aureus, coagulase-negative Staphylococcus, viridans group streptococci, Escherichia coli and Klebsiella pneumoniae, Monte Carlo simulation data showed that probability of target attainment(T>MIC = 70%) is 67% to 97% for dosing every 8 h, and 48% to 88% for dosing every 12 h. For the patients in whom the efficacy of cefozopran could be evaluated, 17 of 22 patients (77.2%) survived the episode of FN without requiring further antibacterial treatment. CONCLUSIONS: Our study proved that Monte Carlo simulation based on population pharmacokinetics can determine optimized dosage and method. The optimal regimen for this cephem was found to be three times daily.

ABT-737 is a useful component of combinatory chemotherapies for chronic myeloid leukaemias with diverse drug-resistance mechanisms.

The effect of ABT-737, a BH3-mimicking inhibitor for anti-apoptotic Bcl-2 and Bcl-X(L), but not Mcl-1, against Bcr-Abl-positive (Bcr-Abl(+)) leukaemic cells was examined. ABT-737 potently induced apoptosis in Bcr-Abl(+) chronic myeloid leukaemia (CML) cell lines and primary CML samples in vitro and prolonged the survival of mice xenografted with BV173 cells, a CML cell line. Higher expression of anti-apoptotic Bcl-2 proteins reduced cell killing by ABT-737 in each cell line, but there was no correlation between the sensitivities to ABT-737 and the specific expression patterns of Bcl-2 family proteins among cell lines. Thus, the cell killing effect of ABT-737 must be determined not only by the expression patterns of Bcl-2 family proteins but also by other mechanisms, such as high expression of Bcr-Abl, or a drug-efflux pump, in CML cells. ABT-737 augmented the cell killing effect of imatinib in Bcr-Abl(+) cells with diverse drug-resistance mechanisms unless leukaemic cells harboured imatinib-insensitive Abl kinase domain mutations, such as T315I. The combination of homoharringtonine that reduces Mcl-1 enhanced the killing by ABT-737 strongly in Bcr-Abl(+) cells even with T315I mutation. These results suggest that ABT-737 is a useful component of chemotherapies for CML with diverse drug-resistance mechanisms.

Real-time therapeutic drug monitoring of cefozopran in plasma using high-performance liquid chromatography with ultraviolet detection.

A simple, rapid, and precise HPLC method using ultrafiltration to remove plasma protein was developed to determine cefozopran concentrations in human plasma for real-time therapeutic drug monitoring. Plasma was separated by centrifugation at 4 degrees C from blood collected in heparinized vacuum tubes. Cefozopran and an internal standard were detected by ultraviolet absorbances at 235 nm with no interfering plasma peak. The calibration curve of cefozopran in human plasma was linear from 0.2 to 200 microg/ml. The limit of detection was 0.05 microg/ml. The assay was applied to febrile neutropenia patients in a clinical setting.

Hyperbaric oxygen in addition to antibiotic therapy is effective for bisphosphonate-induced osteonecrosis of the jaw in a patient with multiple myeloma.

A 60-year-old man with multiple myeloma (MM) (IgG-kappa, stage IIIA) had been treated with minodronate at 6 mg orally as a phase 1 clinical trial for myeloma bone disease for 13 months (total dose, 4032 mg). Then he received incadronate at 10mg intravenously every 1 to 4 weeks (total dose, 350 mg). In July 2005, he complained of mild right mandibular pain, and bone scintigram showed a hot spot at the right side of the mandible. Panoramic radiograph showed osteonecrosis of the jaw (ONJ) and axial and 3-dimensional computed tomography confirmed ONJ. Oral examination showed massive gingival swelling of the right side of the mandible without exposed necrotic bone. He was given clarithromycin in addition to levofloxacin, followed by hyperbaric oxygen (HBO) therapy, which resulted in the complete disappearance of the pain. This is a first reported case of ONJ induced by incadronate. The present case suggests that early detection of ONJ by regular dental check-ups is important in the management of patients with MM who have received bisphosphonate therapy, and HBO in combination with antibiotic therapy is effective in the early stage of ONJ.

The MYO1F, unconventional myosin type 1F, gene is fused to MLL in infant acute monocytic leukemia with a complex translocation involving chromosomes 7, 11, 19 and 22.

We analysed a complex translocation involving chromosomes 7, 11, 19 and 22 in infant acute monocytic leukemia, and identified that the MLL gene on 11q23 was fused to the unconventional myosin type 1F, MYO1F, gene on 19p13.2-13.3. MYO1F consists of at least 28 exons and was predicted to encode a 1098-amino-acid with an N-terminal head domain containing both ATP-binding and actin-binding sequences, a neck domain with a single IQ motif, and a tail with TH1, TH2 and SH3 domains. Northern blot analysis of RNAs prepared from multiple tissues showed that the expression of approximately 4-kb transcripts appeared constant in most tissues examined. However, MYO1F was expressed in only three of 22 leukemic cell lines. The MLL-MYO1F fusion protein contains almost the entire MYO1F, however, C-terminal MYO1F has neither the transactivation domain nor the dimerization domain found in various MLL fusion partners. Further analysis of this novel type of MLL fusion protein would provide new insights into leukemogenesis. MYO1F is the fourth partner gene of MLL on 19p13. At the cytogenetic level, it may be difficult to distinguish MLL-ENL, MLL-ELL, MLL-EEN and MLL-MYO1F fusions created by t(11;19)(q23;p13), and it is likely that cases of t(11;19) lacking a known fusion gene may result in this gene fusion.

Direct evidence for expression of type II flavoprotein subunit in human complex II (succinate-ubiquinone reductase).

Succinate-ubiquinone reductase (complex II) is an important enzyme complex in aerobic respiration and the tricarboxylic acid cycle. We recently identified two distinct cDNAs for the human flavoprotein subunit (Fp) from a single individual and demonstrated mRNAs of these two isoforms, Type I Fp and Type II Fp, in skeletal muscle, liver, brain, heart, and kidney. Type I Fp was expressed at higher levels than Type II Fp in all cases. In the present study, the biochemical properties of Type II Fp-containing complex II in Raji cells predominantly expressing Type II Fp were investigated. Complex II having Type II Fp was separated from that having Type I Fp by isoelectric focusing in the presence of sucrose monolaurate. Together with the fact that succinate-ubiquinone reductase activity of mitochondria prepared from Raji cell was almost identical to that from human liver, these results clearly indicate the presence of two distinct isoforms of active complex II in human mitochondria.

Direct evidence for two distinct forms of the flavoprotein subunit of human mitochondrial complex II (succinate-ubiquinone reductase).

Succinate-ubiquinone reductase (complex II) is an important enzyme complex in both the tricarboxylic acid cycle and aerobic respiration. A recent study showed that defects in human complex II are associated with cancers as well as mitochondrial diseases. Mutations in the four subunits of human complex II are associated with a wide spectrum of clinical presentations. Such tissue-specific clinical symptoms suggest the presence of multiple isoforms of the subunits, but subunit isoforms have not been previously reported. In the present study, we identified two distinct cDNAs for the human flavoprotein subunit (Fp) from a single individual, and demonstrated expression of these two isoforms in skeletal muscle, liver, brain, heart and kidney. Interestingly, one of the Fp isoforms was encoded as an intronless gene.

LCX, leukemia-associated protein with a CXXC domain, is fused to MLL in acute myeloid leukemia with trilineage dysplasia having t(10;11)(q22;q23).

There are a limited number of reports of acute myeloid leukemia (AML) with t(10;11)(q22;q23). We showed that the MLL gene on 11q23 was fused to the LCX (leukemia-associated protein with a CXXC domain) gene on 10q22 in a de novoadult AML-M2 with trilineage dysplasia having t(10;11)(q22;q23). LCX consisted of at least 12 exons and was predicted to encode a 2136-amino-acid protein with an estimated molecular mass of 235.3 kDa. The LCX protein had a zinc-binding CXXC domain that MLL also contains within a methyltransferase domain, three nuclear localization signals, an alpha-helical coiled-coil region, and two homologous regions to CG2083 proteins of Drosophila melanogaster. We found approximately 12-, 9.5-, and 7.5-kb transcripts of LCX. Expression of the 7.5-kb transcript was detected in fetal heart, lung, and brain, and in adult skeletal muscle, thymus, and ovary. Expression of the 9.5-kb transcript was detected in fetal lung and brain and in adult ovary. Expression of the 12-kb transcript was detected in fetal heart and brain and in adult thymus and ovary. LCX was expressed in 8 of 22 leukemic cell lines, but not in EBV-induced normal B-cell lines. The MLL-LCX fusion protein lacked a CXXC domain of LCX, but retained an alpha-helical coiled-coil region at the COOH terminus, similar to MLL-SEPTING, MLL-CDCREL1, MLL-AF1p/Eps15, and MLL-AF6, which suggests that these fusion proteins are involved in the pathogenesis of 11q23-associated leukemia through similar mechanisms.

SEPTIN6, a human homologue to mouse Septin6, is fused to MLL in infant acute myeloid leukemia with complex chromosomal abnormalities involving 11q23 and Xq24.

t(X;11) is a recurrent translocation in pediatric acute myeloid leukemia (AML). We showed that the MLL gene on 11q23 was fused to the SEPTIN6 gene on Xq24, a human homologue to mouse Septin6, in three de novo infant AML with complex chromosomal abnormalities involving 11q23 and Xq22-24. SEPTIN6 consisted of at least 12 exons and was predicted to encode at least two types of proteins by alternative splicing. Expression of approximately 2.3-, 3.1-, and 4.6-kb SEPTIN6 transcripts was simultaneously detected in fetal lung, liver, and brain, in all of the adult tissues except brain, and in acute lymphoblastic leukemia and AML cell lines. However, the expression of an approximately 2.7-kb transcript was detected alone in fetal heart and adult brain. The SEPTIN6 protein is homologous to septin family members including CDCREL1 and AF17q25/MSF, which generate fusion products with MLL. The MLL-SEPTIN6 fusion proteins contain almost the entire septin protein, similar to MLL-CDCREL1 and MLL-AF17q25/MSF. Notably, all three of the patients were diagnosed with M1 or M2. Combined present results and literatures suggest that AML with the MLL-SEPTIN6 fusion gene is a subset of infant AML, which differentiate into the myeloid lineage, although AML with other MLL fusion genes is capable of differentiating into the myelomonocytic or monocytic lineage.