Fumihiko Monma

Correlation Between Imatinib Pharmacokinetics and Clinical Response in Japanese Patients With Chronic-Phase Chronic Myeloid Leukemia

Despite the outstanding results generally obtained with imatinib mesylate (IM) in the treatment of chronic myeloid leukemia (CML), some patients show a poor molecular response. To evaluate the relationship between steady‐state trough plasma IM concentration (IM‐Cmin) and clinical response in CML patients, we integrated data from six independent Japanese studies. Among 254 CML patients, the mean IM‐Cmin was 1,010.5 ng/ml. Importantly, IM‐Cmin was significantly higher in patients who achieved a major molecular response (MMR) than in those who did not (P = 0.002). Multivariate analysis showed that an MMR was associated with both age (odds ratio (OR) = 0.97 (0.958–0.995); P = 0.0153) and with IM‐Cmin (OR = 1.0008 (1.0003–1.0015); P = 0.0044). Given that patients with IM‐Cmin values >1,002 ng/ml had a higher probability of achieving an MMR in our large cohort (P = 0.0120), the data suggest that monitoring of IM levels in plasma may improve the efficacy of IM therapy for CML patients.

Clinical utility of a panfungal polymerase chain reaction assay for invasive fungal diseases in patients with haematologic disorders.

Invasive fungal diseases (IFDs) are life‐threatening events in patients with haematologic disorders, and the spectrum of the aetiological pathogens continues to expand. This study aimed to evaluate the clinical utility of a panfungal polymerase chain reaction (PCR) assay for the management of IFDs in such patients.

Diagnostic Value of PCR Analysis of Bacteria and Fungi from Blood in Empiric-Therapy-Resistant Febrile Neutropenia

ABSTRACT This study aimed to assess the clinical utility of PCR for the analysis of bacteria and fungi from blood for the management of febrile neutropenic patients with hematologic malignancies. Using a PCR system able to detect a broad range of bacteria and fungi, we conducted a prospective pilot study of periodic analyses of blood from patients following intensive chemotherapy. When fever occurred, it was treated with empirical antibiotic therapy, basically without knowledge of the PCR results. In 23 febrile episodes during the neutropenic period, bacteria were detected by PCR in 11 cases, while the same species were identified by blood culture in 3 cases. In 10 out of 11 PCR-positive cases, fever could be managed by empirical therapy. In the empirical-therapy-resistant case, the identification of Stenotrophomonas maltophilia by PCR led to improvement of fever. No fungi were detected by PCR in febrile cases, while Aspergillus fumigatus was detected in one afebrile patient, several days before a clinical diagnosis was made. In subsequent sporadic PCR analyses in 15 cases of febrile neutropenia, bacteria were detected by both PCR and blood culture in 7 cases and by PCR alone in 6. Fungi were not detected. While fever was improved by empirical therapy in 12 out of the 13 PCR-positive cases, the identification of Pseudomonas aeruginosa by PCR in one therapy-resistant case contributed to the successful treatment of persistent fever. Our results indicate that PCR analysis of bacteria from blood provides essential information for managing empirical-therapy-resistant febrile neutropenia.

Long-term outcome and prognostic factors of elderly patients with acute promyelocytic leukemia

Studies focused on elderly acute promyelocytic leukemia (APL) are relatively limited. To evaluate prognostic impact in elderly APL, we compared the long‐term outcome of elderly APL patients (60–70 years) with younger patients (15–59 years) treated with all‐trans retinoic acid combined with anthracycline and cytarabine in the Japan Adult Leukemia Study Group (JALSG) APL97 study. Of 283 evaluable patients, 46 (16.3%) were elderly who had more frequent lower platelet (P = 0.04), lower albumin (P = 0.006) and performance status 3 (P = 0.02), higher induction death rate due to differentiation syndrome (P = 0.03), and non‐relapse mortality (NRM) during consolidation therapy (P = 0.001). Overall survival was significantly inferior in elderly patients (P = 0.005), but disease‐free survival and cumulative incidence of relapse were not. Better therapeutic approaches should be considered to reduce NRM during induction and consolidation therapy in elderly APL. This study was registered at http://www.umin.ac.jp/ctrj/ under C000000206.

Expression of the JAK2 V617F mutation is not found in de novo AML and MDS but is detected in MDS-derived leukemia of megakaryoblastic nature.

Expression of the JAK2 V617F mutation is not found in de novo AML and MDS but is detected in MDS-derived leukemia of megakaryoblastic nature

A potential activity of valproic acid in the stimulation of interleukin-3 mediated megakaryopoiesis and erythropoiesis

OBJECTIVE Although the anticancer activities of histone deacetylase (HDAC) inhibitors have been studied, a role for HDAC in normal hematopoiesis has not been clearly defined. Previous studies have shown that the potent HDAC inhibitor FK228 stimulates interleukin (IL)-3-mediated erythropoiesis. Here, we examined whether the widely used valproic acid (VPA) affects megakaryopoiesis as well as erythropoiesis. MATERIALS AND METHODS CD34(+) cells were incubated in serum-free or serum-containing cultures with cytokines, with or without VPA. RESULTS In the serum-free cultures containing IL-3+stem cell factor (SCF), VPA significantly increased generation of CD61(+)GPA(-) megakaryocytic and a CD61(+)GPA(+) mixture of megakaryocytic and erythroid precursors from CD34(+) hematopoietic precursors at a pharmacological concentration (100 microg/mL). The increase in generation of megakaryocytic and erythroid precursors by VPA was confirmed by replating cultured cells with thrombopoietin+SCF and erythropoietin+SCF, respectively. VPA was as potent as FK228. In cultures with granulocyte-macrophage colony-stimulating factor+SCF, where CD61(-)GPA(+) erythroid precursors were mostly developed, VPA mainly enhanced the generation of CD61(-)GPA(+) erythroid precursors. In serum-containing cultures, only low numbers of CD61(+) or GPA(+) cells were developed with IL-3+SCF. Nevertheless, a substantial number of these cells were generated with VPA. Furthermore, these stimulating effects of VPA were observed by incubating CD34(+) cells from patients with myelodysplastic syndrome. Quantitative reverse transcription polymerase chain reaction showed that VPA enhanced GATA-2, but not GATA-1, messenger RNA expression with IL-3+SCF. CONCLUSIONS These results indicate a novel role for VPA in enhancing the potential of IL-3 to stimulate megakaryopoiesis as well as erythropoiesis and suggest a new therapeutic approach of epigenetic therapy for hematological disease.

IKAROS isoform 6 enhances BCR-ABL1-mediated proliferation of human CD34+ hematopoietic cells on stromal cells.

The BCR-ABL1 induces chronic myelogenous leukemia (CML) and Ph+ acute lymphoblastic leukemia (ALL). Recent studies revealed high ratios of loss of the IKZF1 gene which encodes IKAROS in BCR-ABL1+ ALL and lymphoblastic crisis (LBC) of CML. However, little is known about the cooperativity between the aberrant IKAROS and BCR-ABL1 in primary human hematopoietic cells. We investigated the effects of expression of BCR-ABL1 and/or IK6, a natural dominant negative isoform of IKAROS, on proliferation and differentiation of human CD34+ cord blood cells with or without human bone marrow-derived stromal cells which support early B cell differentiation. Cell proliferation was remarkably enhanced by co-expression of BCR-ABL1 and IK6, with reduced expression of glycophorin A and increased expression of CD41, especially on stromal cells, compared with expression of BCR-ABL1 alone that resulted in expansion of erythroid progenitors. Interestingly, p190BCR-ABL1 showed higher dependency on stromal cells to stimulate cell growth with IK6, than p210BCR-ABL1. Furthermore, the cooperation was found to depend on direct cell adhesive interaction of hematopoietic progenitors with stromal cells. These findings suggest that IK6 and BCR-ABL1 synergistically contribute to leukemogenesis in human bone marrow stromal microenvironment, and may provide a clue to elucidate the mechanisms of leukemogenesis of Ph+ ALL and CML-LBC.

Expression of CD56 is an unfavorable prognostic factor for acute promyelocytic leukemia with higher initial white blood cell counts

Expression of CD56 has recently been introduced as one of the adverse prognostic factors in acute promyelocytic leukemia (APL). However, the clinical significance of CD56 antigen in APL has not been well elucidated. We assessed the clinical significance of CD56 antigen in 239 APL patients prospectively treated with all‐trans retinoic acid and chemotherapy according to the Japan Adult Leukemia Study Group APL97 protocol. All patients were prospectively treated by the Japan Adult Leukemia Study Group APL97 protocol. The median follow‐up period was 8.5 years. Positive CD56 expression was found in 23 APL patients (9.6%). Expression of CD56 was significantly associated with lower platelet count (P = 0.04), severe disseminated intravascular coagulation (P = 0.04), and coexpression of CD2 (P = 0.03), CD7 (P = 0.04), CD34 (P < 0.01) and/or human leukocyte antigen‐DR (P < 0.01). Complete remission rate and overall survival were not different between the two groups. However, cumulative incidence of relapse and event‐free survival (EFS) showed an inferior trend in CD56+ APL (P = 0.08 and P = 0.08, respectively). Among patients with initial white blood cell counts of 3.0 × 109/L or more, EFS and cumulative incidence of relapse in CD56+ APL were significantly worse (30.8% vs 63.6%, P = 0.008, and 53.8% vs 28.9%, P = 0.03, respectively), and in multivariate analysis, CD56 expression was an unfavorable prognostic factor for EFS (P = 0.04). In conclusion, for APL with higher initial white blood cell counts, CD56 expression should be regarded as an unfavorable prognostic factor.

A case of acute myeloblastic leukemia with a novel variant of t(8;21)(q22;q22)

We encountered a case of acute myeloblastic leukemia (AML), with extramedullary leukemia (EML) and a masked type of the variant translocation t(8;21)(q22;q22). Morphologically, the AML M2 subtype according to the French–American–British (FAB) classification was present. Phenotypically, leukemic cells were negative for CD19 and positive for CD56. Clinically, the case showed chemo-refractoriness and a poor outcome. The initial karyotypic interpretation was t(8;9)(q22;q34) on G-banding. Multiplex-fluorescence in situ hybridization (multiplex-FISH) analysis revealed a three-way translocation involving chromosomes 8, 9, and 21, and identified a masked type of variant t(8;21)q22;q22) translocation. The karyotype was finally determined as 45,X,-Y,der(8)t(8;21)(q22;q22), der(9)(8;9)(q22;q34), and der(21)t(9;21)(q34;q22). Results of FISH using the AML1/ETO probe and detection of the AML1/ETO fusion transcripts by reverse transcriptase-polymerase chain reaction (RT-PCR) support the karyotype as well as the sequence of the PCR product. Additionally, C-KIT mutation was detected.

Fluorescent In Situ Hybridization Analysis of Philadelphia Chromosome-Negative Chronic Myeloid Leukemia with the bcr/abl Fusion Gene

This report describes a patient with Philadelphia chromosome-negative (Ph-) but bcr/abl fusion gene-positive chronic myeloid leukemia (CML) and a molecular analysis of the mechanisms behind the Ph- status. Spectral karyotyping-fluorescent in situ hybridization (SKY-FISH) analysis showed no abnormal translocation; however, a bcr/abl fusion gene was detected by reverse transcriptase-polymerase chain reaction analysis. FISH analysis showed that signals from the 9q and 22q subtelomere probes were detected on the der(9) and der(22) chromosomes, respectively. On the other hand, FISH analysis of the abl and bcr genes with dual fusion probes, which can detect the bcr/abl fusion gene on both the der(9) and der(22) chromosomes, showed the signal for bcr/abl fusion on the der(22) chromosome but not on the der(9) chromosome.These results indicate that insertion of the abl gene into the bcr region on the der(22) chromosome or retranslocation between the der(9) chromosome and the der(22) chromosome may have caused the Ph- CML in this case.