Combination of panobinostat with ponatinib synergistically overcomes imatinib-resistant CML cells.

The major mechanism of imatinib (IM) resistance of CML is the reactivation of ABL kinase either through BCR-ABL gene amplification or mutation. We investigated the cytotoxicity of a pan-ABL tyrosine kinase inhibitor, ponatinib, and a pan-histone deacetylase inhibitor, panobinostat, against IM-resistant CML cells in vitro. Two different IM-resistant cell lines, K562/IM-R1 and Ba/F3/T315I were evaluated in comparison with their respective, parental cell lines, K562 and Ba/F3. K562/IM-R1 overexpressed BCR-ABL due to gene amplification. Ba/F3/T315I was transfected with a BCR-ABL gene encoding T315I-mutated BCR-ABL. Ponatinib inhibited the growth of both K562/IM-R1 and Ba/F3/T315I as potently as it inhibited their parental cells with an IC50 of 2-30 nM. Panobinostat also similarly inhibited the growth of all of the cell lines with an IC50 of 40-51 nM. This was accompanied by reduced histone deacetylase activity, induced histone H3 acetylation, and an increased protein level of heat shock protein 70, which suggested disruption of heat shock protein 90 chaperone function for BCR-ABL and its degradation. Importantly, the combination of ponatinib with panobinostat showed synergistic growth inhibition and induced a higher level of apoptosis than the sum of the apoptosis induced by each agent alone in all of the cell lines. Ponatinib inhibited phosphorylation not only of BCR-ABL but also of downstream signal transducer and activator of transcription 5, protein kinase B, and ERK1/2 in both K562/IM-R1 and Ba/F3/T315I, and the addition of panobinostat to ponatinib further inhibited these phosphorylations. In conclusion, panobinostat enhanced the cytotoxicity of ponatinib towards IM-resistant CML cells including those with T315I-mutated BCR-ABL.

[From JSLH (The Japanese Society for Laboratory Hematology): An Active Team Approach to Medicine as Laboratory Technologists, through Showing Bone Marrow and Peripheral Blood Samples Directly to Patients with Hematological Malignancy].

The clinical path for the treatment of acute myeloid leukemia (AML) patients has been in practice in our hospital since 2003. In the clinical path, laboratory technologists take on the role of explaining the microscopic findings in bone marrow and peripheral blood samples to patients (with or without their families) using the view-sharing microscope in our laboratory. From July 2003 to October 2014, 56 patients were enrolled in the AML clinical path and given an explanation of their bone marrow and peripheral blood samples. The patients' median age was 62, and the median time spent for explanation was 40 minutes. We conducted a questionnaire feedback survey involving those who enrolled, and the results showed significant improvement in the recognition of the disease pathophysiology, treatment efficacy, and the importance of precautions against infectious diseases. Based on the feedback, we have made marked efforts to provide patients with an improved environment during the explanatory session. This includes installing a special display for the patients, drawing a schematic illustration that shows how the blood cells differentiate, and putting them into operation in a hematology ward to promote patient privacy and precautions against infectious diseases. Hematological laboratory technologists have played an important role in patient care in our hospital. To perform their role as effectively as possible, hematological laboratory technologists participate in the conferences of the Department of Hematology and Oncology regularly, in which medical staff members can discuss the conditions and clinical courses of patients. We aim to contribute to patient satisfaction by sophisticating specialized knowledge as hematological laboratory technologists and cooperate with other medical staff members.

Efficacy and Safety of Caspofungin Treatment in Febrile Neutropenic Patients with Hematological Disorders: A Multicenter Consecutive Case Series.

Introduction Invasive fungal infections have been attracting attention as significant fatal complications in patients with febrile neutropenia (FN) who undergo intensive chemotherapy or hematopoietic stem cell transplantation to treat hematological malignancies. Although clinical trials are already underway in other countries, evidence supporting the use of caspofungin (CAS) in FN patients in Japan is still insufficient. Methods A retrospective study of patients treated with CAS for FN associated with hematological diseases between April 2015 and March 2018 was conducted to determine the treatment efficacy and safety. The study was conducted as a multicenter collaboration, and the data of 52 patients who met all of the inclusion criteria were analyzed. A five-composite-endpoint method was used, and the treatment was judged to be effective when all five endpoints (defervescence during neutropenia; no breakthrough fungal infections; resolution of baseline fungal infections; a survival for seven days or more after the completion of therapy; and no discontinuation of therapy due to side effects or invalidity) were met. Results The efficacy rate was 53.8% (28/52), which is close to the average reported efficacy rate. Adverse events included liver dysfunction and electrolyte abnormalities, but no renal dysfunction or serious events were seen. Conclusion These results suggest that the use of CAS in FN patients with hematological diseases is effective and well-tolerated, and we believe that the use of CAS could become a significant treatment in Japan.

Overcoming imatinib resistance using Src inhibitor CGP76030, Abl inhibitor nilotinib and Abl/Lyn inhibitor INNO-406 in newly established K562 variants with BCR-ABL gene amplification.

Because imatinib (IM) resistance in chronic myeloid leukemia is primarily caused by the re-establishment of Abl kinase, new inhibitors may be efficacious. We evaluated 3 new agents against 2 new K562 variants, IM-R1 and IM-R2 cells, which were developed having 7- and 27-fold greater IM resistance, respectively, than the parental K562 cells. Both variants possessed BCR-ABL gene amplification along with elevated levels of its transcript and protein. Greater BCR-ABL gene amplification was observed in IM-R2 cells than in IM-R1 cells, which was consistent with the higher mRNA and protein levels of Bcr-Abl, and ultimately correlated with the greater IM resistance in IM-R2 cells. No mutation in the Abl kinase domain was detected in either variant. Despite the absence of Lyn overexpression, the Src kinase inhibitor CGP76030 showed positive cooperability with IM in inhibiting cell growth of not only K562 cells but also these 2 variants. This might be because of the augmented inhibition of Erk1/2 phosphorylation. The new Abl kinase inhibitor nilotinib was 10-fold more potent than IM in inhibiting the growth of K562 cells. Nilotinib inhibited the growth of IM-R1 and IM-R2 cells as potently as K562 cells. The combination of nilotinib with CGP76030 showed little additivity, because the potency of nilotinib masked the efficacy of CGP76030. The new dual Abl/Lyn inhibitor INNO-406 (formerly NS-187) was slightly more potent than nilotinib in inhibiting the growth of all 3 cell lines. Because BCR-ABL gene amplification occurs in blast crisis, these inhibitors might overcome IM resistance in such patients' leukemia.

A randomized comparison of modified intermediate-dose Ara-C versus high-dose ara-c in post-remission therapy for acute myeloid leukemia.

BACKGROUND: We conducted a prospective, multicenter cooperative study to compare two courses of modified intermediate-dose cytarabine (Ara-C) (mIDAC; Ara-C at a dose of 1.0 g/m(2) every 12 hours for 5 days) versus high-dose Ara-C (HDAC; Ara-C at a dose of 2.0 g/m(2) every 12 hours for 5 days) in post-remission therapy for acute myeloid leukemia (AML) to confirm the post-remission antileukemic efficacy and safety of mIDAC. PATIENTS AND METHODS: Twenty-six newly diagnosed patients with AML underwent remission induction therapy consisted of behenoyl Ara-C, mitoxantrone, etoposide, and 6-mercaptopurine. Post-remission therapy included four courses of consolidation and four courses of intensification. Patients who achieved complete remission (CR) were randomly assigned to mIDAC or HDAC for the second course of consolidation. The third course of intensification was the same as the second course of consolidation. Other post-remission therapies were the same in each group. RESULTS: Twenty-two patients (84.6%) achieved CR and 21 patients were randomly assigned to receive either mIDAC (n=11) or HDAC (n=10). The predicted 4-year relapse-free survival for the mIDAC group and for the HDAC group were 49% and 56%, respectively (p=0.86). Although HDAC developed severe leukocytopenia compared to mIDAC, there were no significant differences between HDAC and mIDAC in the incidence of ≥grade 3 and ≥grade 4 documented infections. The mean lowest white blood cell count (WBC) after HDAC was significantly lower than that after mIDAC (0.208±0.120×10(3)/mm(3) and 0.459±0.333×10(3)/mm(3), respectively, p<0.05). The time to WBC recovery to 2.0×10(3)/mm(3) after HDAC was significantly longer than that after mIDAC (34.3±12.1 days and 27.1±9.5 days, respectively, p<0.05). CONCLUSION: This study suggests that mIDAC may have an equivalent post-remission antileukemic efficacy to HDAC with less myelosuppression for AML patients.