Outcomes of adult patients with early T-cell precursor (ETP) acute lymphoblastic leukemia/lymphoma (ALL) and non-ETP T-ALL.

Early T-cell precursor (ETP) acute lymphoblastic leukemia/lymphoma (ALL) is generally considered to be a high-risk subtype. We retrospectively analyzed the clinical outcomes of adult patients diagnosed with ETP-ALL or other T-cell ALL (non-ETP T-ALL). The subjects were 82 patients (ETP-ALL: n = 18, non-ETP T-ALL: n = 64) for whom relevant immunophenotype data needed for classification were available. ETP-ALL patients were older (median age, 50.5 vs. 33.5 years, P = 0.042) and had less mediastinal involvement (27.8 vs. 73.4%, P < 0.001). The rate of complete remission (CR) with the first induction therapy was significantly lower in the ETP group (33.3 vs. 64.0%, P = 0.03), but the CR rate within 2 cycles of chemotherapy did not differ significantly (61.1 vs. 76.6%, P = 0.232). The 3-year overall survival (OS) rate was also similar in both groups (43.2 vs. 45.8%, P = 0.992). The ETP phenotype had no impact on survival in the transplant group or the non-transplant group. A multivariate analysis identified the male sex as a poor prognostic factor (HR: 4.43, P < 0.01), but not the immunophenotype of ETP. The prognosis for adult patients with ETP-ALL was comparable to that of non-ETP T-ALL patients. However, further studies aimed at improving the remission rate for ETP-ALL are needed.

[Retroperitoneal Malignant Lymphoma: A Case Report].

A male patient in his 70s was referred to our hospital with the chief complaint of anorexia. Abdominal computed tomography (CT) showed a 20 cm large homogeneous mass in the retroperitoneum, and contrast-enhanced CT revealed uniform staining throughout the inside of the mass. Soluble interleukin-2 receptor and lactate dehydrogenase tumor markers were elevated. Hence, malignant lymphoma was suspected, and ultrasonography-guided biopsy was performed. Histopathological findings showed large lymphocytes with poorly differentiated cytoplasmic nucleoli and positivity for CD20 and CD79a via immunohistochemical analysis, which was consistent with diffuse large B-cell lymphoma. The patient received R-THP-COP therapy which consisted of rituximab, pirarubicin, cyclophosphamide, vincristine and prednisolone. After four chemotherapy courses, a partial response according to the the response evaluation criteria in solid tumors was obtained. The patient was discharged with no signs of recurrence.

Importance of TKI treatment duration in treatment-free remission of chronic myeloid leukemia: results of the D-FREE study.

Treatment-free remission (TFR) is a new goal for patients with chronic myeloid leukemia in chronic phase (CML-CP) with a sustained deep molecular response (DMR) to treatment with tyrosine kinase inhibitors (TKIs). However, optimal conditions for successful TFR in patients treated with second-generation (2G)-TKIs are not fully defined. In this D-FREE study, treatment discontinuation was attempted in newly diagnosed CML-CP patients treated with the 2G-TKI dasatinib who achieved BCR-ABL1 levels of ≤ 0.0032% (MR4.5) on the international scale (BCR-ABL1IS) and maintained these levels for exactly 1 year. Of the 173 patients who received dasatinib induction therapy for up to 2 years, 123 completed and 60 (48.8%) reached MR 4.5. Among the first 21 patients who maintained MR4.5 for 1 year and discontinued dasatinib, 17 experienced molecular relapse defined as loss of major molecular response (BCR-ABL1IS > 0.1%) confirmed once, or loss of MR4 (BCR-ABL1IS > 0.01%) confirmed on 2 consecutive assessments. The estimated molecular relapse-free survival rate was 16.7% at 12 months. This study was prematurely terminated according to the protocol's safety monitoring criteria. The conclusion was that sustained DMR for just 1 year is insufficient for TFR in CML-CP patients receiving dasatinib for less than a total of 3 years of treatment.

Renal injury associated with MYH9 disorder with 5773delG mutation: A case report.

A 35-year-old man with persistent urine abnormalities and renal dysfunction was referred to our hospital. May-Hegglin anomaly was suspected, and a renal biopsy showed focal segmental glomerulosclerosis (FSGS) with IgA deposition. Electron microscopy revealed foot process effacements and intense bleb-like morphological changes in podocytes. Nonmuscle myosin heavy chain IIA (NMMHCIIA) staining of granulocytes revealed a localized, type II pattern, and genomic DNA sequencing of MYH9 exon 40 revealed MYH9 5773delG mutation (c.5773delG [p.(Asp1925Thrfs*23)]). Podocytes were significantly stained by an antibody specific for NMMHC-IIA abnormalities associated with this mutation. Colocalization observation of vimentin and NMMHC-IIA demonstrated a diminished form of NMMHC-IIA in podocytes. Taking these observations into account, it was determined that the present case was likely associated with MYH9 disorder. Treatment was started with olmesartan, followed by methylprednisolone pulse therapy 3 times bi-monthly. Finally, the patient began hemodialysis 18 months later. This is the first known report of renal phenotype expression associated with this MYH9 mutation. FSGS can occur in association with MYH9 mutations at the 3' regions, such as exon 40. Abnormal expression or metabolism of NMMHC-IIA in podocytes might be related to the formation of FSGS lesions due to this MYH9 mutation.

[Development of severe aplastic anemia during steroid therapy for autoimmune hemolytic anemia].

A 50-year-old male patient was admitted for close monitoring of anemia (hemoglobin level, 5.0 g/dl). Autoimmune hemolytic anemia (AIHA) of warm type was diagnosed based on the elevated reticulocyte and bone marrow erythroblast counts, elevated indirect bilirubin level, serum haptoglobin level below the detection limit, and positive direct Coombs test result. The patient responded to prednisolone 60 mg/day (1.0 mg/kg); however, pancytopenia was observed during gradual dose tapering and maintenance therapy. The bone marrow showed remarkable hypoplastic findings, and magnetic resonance imaging scans of the thoracolumbar spinal cord showed an overgrowth of the adipose tissue. Thus, the patient was diagnosed with aplastic anemia (AA) stage 4. He was successfully treated with a combination of immunosuppressive therapy (anti-thymocyte globulin +cyclosporine), which allowed him to reduce his dependence on transfusions. However, the direct Coombs test result remained positive even after hematopoietic recovery. Aplastic anemia following AIHA treatment is extremely rare and has not been reported previously.

Low-dose dasatinib in older patients with chronic myeloid leukaemia in chronic phase (DAVLEC): a single-arm, multicentre, phase 2 trial.

BACKGROUND: BCR-ABL1 tyrosine kinase inhibitors (TKIs) are commonly initiated in older patients with chronic myeloid leukaemia in the chronic phase at standard doses. However, because of their safety profile in this population, appropriate therapy has not been established. We aimed to investigate whether a lower than standard dose of dasatinib was an appropriate therapy for older patients with chronic myeloid leukaemia in the chronic phase. METHODS: DAsatinib, Very Low-dose, for Elderly CML-CP patients (DAVLEC) was a multicentre, single-arm, phase 2 trial done in 25 Japanese hospitals. We enrolled patients older than 70 years with newly diagnosed chronic myeloid leukaemia in the chronic phase, ECOG performance status 0-2, and no previous treatment for CML other than hydroxyurea within 4 weeks. Second-generation TKI dasatinib was given orally at a starting dose of 20% of the standard dose (20 mg/day). If the treatment was assessed as optimal response at 3 months, 6 months, and 9 months and adverse events were grade 2 or better (according to the NCI Common Toxicity Criteria v 4.0), the same dose was continued. If response was suboptimal and adverse events were grade 2 or better, the dose was increased by 20 mg/day. Once a dose reduction had been made because of a grade 3 or worse adverse event, there were no further dose increases. Treatment was discontinued if assessed as failure (disease progression to the accelerated phase or acute phase). The primary endpoint was the achievement of major molecular response at 12 months, assessed using a per-protocol analysis. This trial is registered at with the UMIN clinical trial registry, UMIN000024548, and has completed its planned observation period. FINDINGS: Between Nov 1, 2016, and Oct 30, 2019, 52 patients received first-line dasatinib therapy at 20 mg/day. The median age at diagnosis was 77·5 years (73·5-83·0). 35 (67%) patients were male and 17 (33%) were female. 31 (60%) of 52 patients reached major molecular response at 12 months (one-sided 95% CI 48-71), with a median follow-up of 366 days (IQR 353-372). Grade 3-4 adverse events were reported in 12 (23%) patients. Neutropenia was the most frequent grade 3-4 adverse event, occurring in three (6%) patients. No treatment-related deaths were observed. INTERPRETATION: Low-dose dasatinib at 20mg/day is worthy of consideration as a starting dose for older patients with newly diagnosed chronic myeloid leukaemia in the chronic phase. However, this dose needs to be further studied in a larger cohort and with a more ethnically diverse population. FUNDING: Bristol-Myers Squibb.

Second direct-acting antiviral therapy for hepatitis C virus infection after umbilical cord blood transplantation: A case report.

Hepatitis C virus (HCV) infection has an adverse impact on outcomes after allogeneic hematopoietic stem cell transplantation (HSCT). It is recommended that HSCT candidates infected with HCV receive the treatment prior to transplantation. Although the recent approval of direct-acting antivirals (DAAs) has led to great advances in the treatment of HCV infection, little information is available on the efficacy and safety of DAA therapy in patients receiving allogeneic HSCT. Herein, we report the clinical course of an umbilical cord blood (UCB) recipient treated with DAAs for HCV infection. The patient achieved HCV RNA negativity with glecaprevir and pibrentasvir after consolidation therapy for acute myeloid leukemia (AML), and underwent transplantation before confirming sustained virological response (SVR) at 12 weeks. The HCV viral load became detectable on day +28 after transplantation and second HCV treatment with sofosbuvir, velpatasvir, and ribavirin was required. It is important to confirm SVR prior to transplantation, but it is often difficult. If early transplantation is required, close monitoring of HCV RNA after transplantation is needed. Further investigation is required to clarify the optimal management of HCV infection for allogeneic HSCT recipients in the DAA era.

Treatment-free remission after first-line dasatinib discontinuation in patients with chronic myeloid leukaemia (first-line DADI trial): a single-arm, multicentre, phase 2 trial.

BACKGROUND: A previous dasatinib discontinuation (DADI) trial showed that 31 (49%) of 63 patients with chronic-phase chronic myeloid leukaemia who were treated with second-line or subsequent dasatinib could discontinue the drug safely. However, the safety and efficacy of discontinuing first-line dasatinib remains unclear. In this trial (the first-line DADI trial) we aimed to assess molecular relapse-free survival at 6 months after discontinuation of dasatinib in patients with chronic myeloid leukaemia who had been treated with first-line dasatinib and had maintained deep molecular response for at least 1 year. METHODS: The first-line DADI trial was a single-arm, multicentre, phase 2 trial done at 23 hospitals in Japan. Patients with newly diagnosed chronic-phase chronic myeloid leukaemia without hepatosplenomegaly and extramedullary mass, who received at least 24-month dasatinib treatment and had a sustained deep molecular response (defined as BCR-ABL1/ABL1 international scale ≤0·0069% in at least four successive samples spanning a 12 month period) were enrolled. Other eligibility criteria were an age of 15 years or older, an Eastern Cooperative Oncology Group performance status score of 0-2, and no primary organ dysfunction. The primary outcome was molecular relapse-free survival (also known as treatment-free remission) after discontinuation of dasatinib at 6 months and was analysed in all patients who completed the 12-month consolidation phase. Safety was assessed in all patients who received treatment. This study closed early due to accrual and is registered with the UMIN Clinical Trials Registry (UMIN000011099). FINDINGS: Between Sept 20, 2013 and July 12, 2016, 68 patients who had a deep molecular response after receiving first-line dasatinib for at least 24 months were enrolled and assigned to the consolidation phase. Nine patients were excluded during the consolidation phase and one patient was excluded after study completion because of meeting exclusion criteria. 58 patients discontinued dasatinib and were assessed. 32 (55%) of 58 patients had treatment-free remission at 6 months after dasatinib discontinuation, and median follow-up was 23·3 months (IQR 11·7-31·0). Treatment-free remission at 6 months was 55·2% (95% CI 43·7-69·6). No non-haematological adverse events worse than grade 2 occurred before dasatinib discontinuation. The most common haematological adverse event was anaemia (14 [21%] of 68 treated patients); three (4%) of 68 treated patients had grade 3 neutropenia and one (1%) had grade 4 lymphopenia. INTERPRETATION: Our findings suggest that dasatinib could be safely discontinued after first-line treatment in patients with chronic myeloid leukaemia who had received at least 36 months of therapy and sustained deep molecular response; however, further confirmation in larger trials is needed. FUNDING: Epidemiological and Clinical Research Information Network.

[Acquired hemophilia A accompanied by immune thrombocytopenia].

A 72-year-old man was hospitalized because of thrombocytopenia (0.5×104/µl) and anemia. The bone marrow test result revealed excessive numbers of megakaryocytes and no platelet adhesion. Furthermore, platelet-associated immunoglobulin G levels were high, and he was tested positive for Helicobacter pylori antibody. On the basis of these findings, immune thrombocytopenia was diagnosed. The patient was initially treated with eradication therapy; prednisolone, 20 mg/day (0.5 mg/kg) and a thrombopoietin receptor agonist 12.5 mg/day. During the course of treatment, the anemia worsened. Detailed examination revealed marked prolongation of activated partial thromboplastin time and inhibition of factor VIII activity. Therefore, he was diagnosed with acquired hemophilia A. Although extensive muscle hemorrhage had occurred, hemostatic therapy comprising intensification of the immunosuppressive therapy and administration of recombinant activated factor VII resulted in successful hemostasis. As the treatment progressed, inhibition of factor VIII recurred temporarily; however, immunosuppressive therapy was continued. No recurrence was observed even after 1 year of the onset of both diseases.

Safety and efficacy of high-dose ranimustine (MCNU) containing regimen followed by autologous stem cell transplantation for diffuse large B-cell lymphoma.

High-dose chemotherapy followed by autologous stem cell transplantation (ASCT) is widely used as a salvage therapy for relapsed or high-risk diffuse large B-cell lymphoma (DLBCL). To investigate the safety and efficacy of regimens including high-dose MCNU followed by ASCT for DLBCL, we analyzed the data from prospective multicenter trials. Twenty-nine patients were analyzed, and the median follow-up time for survival patients was 70 months. Fifteen patients received MCVC conditioning regimen, and fourteen patients received MEAM regimen. Major toxicities associated with these conditioning regimens included nausea (69%), anorexia (66%), febrile neutropenia (62%), diarrhea (59%), and mucositis (34%). One patient who developed severe sinusoidal obstructive syndrome and acute lung injury died without disease progression, and overall therapy-related mortality at 5 years was 3%. No patient developed therapy-related hematological malignancy. At 5 years, overall survival and progression-free survival in all patients were 82.8 and 58.2%, respectively. The 5-year OS in patients treated by the MCVC and MEAM regimens were 73.3 and 92.9%, respectively. These results suggest that regimens including high-dose MCNU followed by ASCT are feasible and effective for the treatment of relapsed or high-risk DLBCL. Further investigation is needed to evaluate of these regimens.

Pretreatment evaluation of fluorescence resonance energy transfer-based drug sensitivity test for patients with chronic myelogenous leukemia treated with dasatinib.

Tyrosine kinase inhibitors (TKI) are used for primary therapy in patients with newly diagnosed CML. However, a reliable method for optimal selection of a TKI from the viewpoint of drug sensitivity of CML cells has not been established. We have developed a FRET-based drug sensitivity test in which a CrkL-derived fluorescent biosensor efficiently quantifies the kinase activity of BCR-ABL of living cells and sensitively evaluates the inhibitory activity of a TKI against BCR-ABL. Here, we validated the utility of the FRET-based drug sensitivity test carried out at diagnosis for predicting the molecular efficacy. Sixty-two patients with newly diagnosed chronic phase CML were enrolled in this study and treated with dasatinib. Bone marrow cells at diagnosis were subjected to FRET analysis. The ΔFRET value was calculated by subtraction of FRET efficiency in the presence of dasatinib from that in the absence of dasatinib. Treatment response was evaluated every 3 months by the BCR-ABL1 International Scale. Based on the ΔFRET value and molecular response, a threshold of the ΔFRET value in the top 10% of FRET efficiency was set to 0.31. Patients with ΔFRET value ≥0.31 had significantly superior molecular responses (MMR at 6 and 9 months and both MR4 and MR4.5 at 6, 9, and 12 months) compared with the responses in patients with ΔFRET value <0.31. These results suggest that the FRET-based drug sensitivity test at diagnosis can predict early and deep molecular responses. This study is registered with UMIN Clinical Trials Registry (UMIN000006358).

Final 3-year Results of the Dasatinib Discontinuation Trial in Patients With Chronic Myeloid Leukemia Who Received Dasatinib as a Second-line Treatment.

INTRODUCTION: We previously reported an interim analysis of the DADI (dasatinib discontinuation) trial. The results showed that 48% of patients with chronic myeloid leukemia in the chronic phase who maintained a deep molecular response (DMR) for ≥ 1 year could discontinue second- or subsequent-line dasatinib treatment safely at a median follow-up of 20 months. However, the results from longer follow-up periods would be much more useful from a clinical perspective. PATIENTS AND METHODS: The DADI trial was a prospective, multicenter trial conducted in Japan. After confirming a stable DMR for ≥ 1 year, dasatinib treatment subsequent to imatinib or nilotinib was discontinued. After discontinuation, the loss of DMR (even of 1 point) was defined as stringent molecular relapse, thereby triggering therapy resumption. The predictive factors of treatment-free remission (TFR) were analyzed. RESULTS: The median follow-up period was 44.0 months (interquartile range, 40.5-48.0 months). The estimated overall TFR rate at 36 months was 44.4% (95% confidence interval, 32.0%-56.2%). Only 2 patients developed a molecular relapse after the 1-year cutoff point. The presence of imatinib resistance was a significant risk factor for molecular relapse. Moreover, high natural killer cell and low γδ+ T-cell and CD4+ regulatory T-cell (CD25+CD127low) counts before discontinuation correlated significantly with successful therapy discontinuation. CONCLUSION: These findings suggest that discontinuation of second- or subsequent-line dasatinib after a sustained DMR of ≥ 1 year is feasible, especially for patients with no history of imatinib resistance. In addition, the natural killer cell count was associated with the TFR.

Rapid reduction in BCR-ABL1 transcript predicts deep molecular response in dasatinib-treated chronic-phase chronic myeloid leukaemia patients.

OBJECTIVES: We conducted a phase-II study to evaluate the efficacy and safety of dasatinib in patients newly diagnosed with chronic-phase chronic myeloid leukaemia (CML-CP) in Japan (IMIDAS PART 2 study). METHODS: Seventy-nine patients were administered 100 mg dasatinib once daily. We examined pretreatment and post-treatment influences of various factors. The BCR-ABL1 international scale (IS), halving time (HT) and reduction rate of BCR-ABL1 transcript within the initial 1 or 3 months of therapy (RR-BCR-ABL11m,3m ) were the post-treatment factors investigated to predict the molecular response. RESULTS: The estimated major molecular response (MMR), molecular response 4.0 (MR4.0) and molecular response 4.5 (MR4.5) rates were 77.2%, 49.4% and 35.4%, respectively, at 12 months. Grade 3/4 non-haematologic adverse events were infrequent. Multivariate analysis showed that age >65 years was significantly correlated with MR4.0 and MR4.5 (deep molecular response: DMR) at 12 months. All post-treatment factors at 3 months predicted DMR by univariate analysis. However, RR-BCR-ABL13m was the only significant landmark for predicting DMR by multivariate analysis. CONCLUSIONS: Primary treatment of CML-CP with dasatinib enabled early achievement of MMR and DMR, particularly in elderly patients, with high safety. Furthermore, RR-BCR-ABL13m was found to be a more useful predictor of DMR than HT-BCR-ABL1 and BCR-ABL1 IS.

Evaluation of the safety and efficacy of recombinant soluble thrombomodulin for patients with disseminated intravascular coagulation associated with acute leukemia: multicenter prospective study by the Tohoku Hematology Forum.

It has been suggested that use of recombinant soluble thrombomodulin (rTM) is superior to conventional drugs in treatment of disseminated intravascular coagulation (DIC) complicating acute leukemia. However, its safety and efficacy have not been fully examined in prospective studies. Here, we performed a multicenter prospective study to examine outcomes of rTM treatment for DIC in patients with acute leukemia. Of 33 patients registered in this study, 13 had acute myeloid leukemia (AML), three had acute lymphoblastic leukemia (ALL), and 17 had acute promyelocytic leukemia (APL). The cumulative rates of DIC resolution at day 7 and day 35 were 56 and 81% in AML/ALL and 53 and 77% in APL, respectively. The median time from the initiation of rTM to DIC resolution was 4 days in AML/ALL and 6 days in APL patients. Adverse events related to hemorrhage occurred in two AML/ALL patients (13%) and three APL patients (18%). Of these, one AML/ALL patient died with intracranial hemorrhage, and two APL patients died with intracranial hemorrhage and pulmonary hemorrhage. These results suggest that rTM may improve the survival of acute leukemia patients with DIC by inhibiting early death related to hemorrhagic events, as reported previously.

Causes of macrocytic anemia among 628 patients: mean corpuscular volumes of 114 and 130 fL as critical markers for categorization.

There have been no studies on the distribution of causes of macrocytic anemia with respect to mean corpuscular volume (MCV) cutoff values. We retrospectively investigated the causes of macrocytic anemia (MCV ≥100 fL) among 628 patients who visited the outpatient hematology clinic in Tohoku University Hospital. To ensure data validity, we also analyzed data from 307 patients in eight other hospitals in the Tohoku district. The leading causes of macrocytic anemia (number of patients, %) were myelodysplastic syndromes (121, 19.3 %), suspected bone marrow failure syndromes (BMF; 74, 11.8 %), aplastic anemia (51, 8.1 %), plasma cell dyscrasia (45, 7.2 %), and vitamin B12 deficiency (40, 6.4 %) in Tohoku University Hospital. We made three primary findings as follows. First, the most common cause of macrocytic anemia is BMF. Second, lymphoid and solid malignancies are also common causes of macrocytosis. Third, macrocytic anemia may be classified into three groups: Group 1 (megaloblastic anemia and medications), which can exceed MCV 130 fL; Group 2 (alcoholism/liver disease, BMF, myeloid malignancy, and hemolytic anemia), which can exceed MCV 114 fL; and Group 3 (lymphoid malignancy, chronic renal failure, hypothyroidism, and solid tumors), which does not exceed MCV 114 fL. These conclusions were supported by the results from eight other hospitals.

High prevalence of diffuse large B-cell lymphoma in occult hepatitis B virus-infected patients in the Tohoku district in Eastern Japan.

Occult hepatitis B virus (HBV) infection is a clinical challenge, but its relationship to clinicopathologic features and the risk of progression to malignant lymphoma (ML) are poorly defined. We estimated the prevalence of HBV infection of 1,358 patients with newly diagnosed ML. HBV infection was more prevalent in ML than in control patients. The occult HBV infection group had a higher median onset age, no liver or spleen involvement, and higher prevalence of diffuse large B-cell lymphoma than the other groups, indicating that occult HBV infection is a distinct clinicopathologic entity. J. Med. Virol. 88:2206-2210, 2016. © 2016 Wiley Periodicals, Inc.

Comparison of micafungin and voriconazole as empirical antifungal therapies in febrile neutropenic patients with hematological disorders: a randomized controlled trial.

OBJECTIVES: In cases of hematological malignancy, patients with persistent fever and neutropenia receive antifungal empirical therapy to prevent and treat invasive fungal infections. The clinical efficacy and safety of micafungin and voriconazole were compared. METHODS: In this randomized, cooperative group, open-label trial, we assessed and compared the efficacy and safety of micafungin and voriconazole as an empirical antifungal therapy in febrile neutropenic patients with hematological malignancy. Patients were classified according to invasive fungal infection risk. RESULTS: There were no significant differences in clinical efficacy between the two treatments, evaluated based on (i) successful treatment of baseline fungal infection (no evaluation), (ii) absence of breakthrough fungal infection (P = 0.106), (iii) survival for ≥7 days after study completion (P = 0.335), (iv) premature study discontinuation due to poor efficacy (P = 0.424), and (v) resolution of fever during neutropenia (P = 0.756). Discontinuation due to drug-related adverse events (grades 3-4) occurred less frequently in the micafungin group (P = 0.005). CONCLUSIONS: The clinical efficacy did not differ between micafungin and voriconazole. Micafungin was generally better tolerated than voriconazole when given as an empirical antifungal therapy in patients with persistent fever and neutropenia.

Pharmacokinetics and pharmacodynamics of dasatinib in the chronic phase of newly diagnosed chronic myeloid leukemia.

PURPOSE: Dasatinib is a novel, oral, multi-targeted kinase inhibitor of breakpoint cluster region-abelson (BCR-ABL) and Src family kinases. The study investigated pharmacokinetic (PK) and pharmacodynamic (PD) analyses of dasatinib in 51 newly diagnosed, chronic phase, chronic myeloid leukemia patients. METHODS: The dasatinib concentration required to inhibit 50 % of the CrkL (CT10 regulator of kinase like) phosphorylation in bone marrow CD34+ cells (half maximal (50 %) inhibitory concentration (IC50)CD34+cells) was calculated from each patient's dose-response curve using flow cytometry. PK parameters were obtained from the population pharmacokinetic analysis of dasatinib concentrations in plasma on day 28 after administration. RESULTS: Early molecular responses were not significantly associated with PK or PD (IC50 CD34+cells) parameters. However, the PK/PD parameter-time above IC50 CD34+cells-significantly correlated with BCR-ABL transcript level at 3 months (correlation coefficient (CC) = -0.292, P = 0.0375) and the reduction of BCR-ABL level at 1 or 3 months (CC = -0.404, P = 0.00328 and CC = -0.356, P = 0.0104, respectively). Patients with more than 12.6 h at time above IC50 CD34+cells achieved a molecular response of 3.0 log reduction at 3 months and those more than 12.8 h achieved a deep molecular response less than 4.0 log reduction at 6 months at a significantly high rate (P = 0.013, odds ratio = 4.8 and P = 0.024, odds ratio = 4.3, respectively). CONCLUSION: These results suggest that the anti-leukemic activity of dasatinib exhibits in a time-dependent manner and that exposure for more than 12.8 h at time above IC50 CD34+cells could significantly improve prognosis.

Discontinuation of dasatinib in patients with chronic myeloid leukaemia who have maintained deep molecular response for longer than 1 year (DADI trial): a multicentre phase 2 trial.

BACKGROUND: First-line imatinib treatment can be successfully discontinued in patients with chronic myeloid leukaemia after deep molecular response has been sustained for at least 2 years. We investigated the safety and efficacy of discontinuing second-line or subsequent dasatinib after at least 1 year of deep molecular response. METHODS: The Dasatinib Discontinuation trial was a prospective multicentre trial done in Japan. Eligible patients taking dasatinib and with confirmed stable deep molecular response were enrolled between April 1, 2011, and March 31, 2012. All patients received dasatinib consolidation therapy for at least 1 year. In those with sustained deep molecular response, dasatinib was discontinued. Patients were followed up every month in year 1 (clinical cutoff), every 3 months in year 2, and every 6 months in year 3 for deep molecular response and immunological profiles. The primary endpoint was the proportion of patients with treatment-free remission at 6 months after discontinuation. Molecular relapse was defined as loss of deep molecular response at any assessment. This study is registered, number UMIN000005130. FINDINGS: 88 patients were enrolled in the consolidation phase, 24 were excluded from the discontinuation phase due to fluctuations in BCR-ABL1 transcript levels. One patient was excluded because of positive expression of major and minor BCR-ABL1 transcripts in chronic myeloid leukaemia cells and the detection of minor BCR-ABL1 transcripts during consolidation. Thus, 63 patients discontinued dasatinib treatment. The 25 patients who were excluded from discontinuation continued to receive dasatinib and none showed disease progression. Median follow-up was 20.0 months (IQR 16.5-24.0). Of the 63 patients who discontinued and were not excluded, 30 patients maintained deep molecular response while 33 patients had molecular relapses, all within the first 7 months after discontinuation. The estimated overall treatment-free remission was 49% (95% CI 36-61) at 6 months. No severe treatment-related toxic effects were seen. Treatment was restarted in the 33 patients with relapse; rapid molecular responses were seen in all 33 patients, of whom 29 (88%) regained deep molecular response within 3 months, as did the remaining four by 6 months. INTERPRETATION: Dasatinib discontinuation after sustained deep molecular response for more than 1 year is feasible. FUNDING: Epidemiological and Clinical Research Information Network (ECRIN).