Utility of allogeneic stem cell transplantation for adult Ph+ALL with complete molecular remission.

This study aimed to investigate the usefulness of allogeneic stem cell transplantation (allo-SCT) for Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ALL) in the first complete remission (CR1) with complete molecular remission (CMR). We compared the outcomes between Ph+ALL patients who did or did not undergo allo-SCT in CR1. We included patients enrolled in the prospective clinical studies in the tyrosine kinase inhibitor era conducted by the Japan Adult Leukemia Study Group, who achieved CMR within 3 months. A total of 147 patients (allo-SCT: 101; non-SCT: 46) were eligible for this analysis. In the multivariate analyses, allo-SCT was significantly associated with both superior overall survival (OS) (adjusted hazard ratio (aHR): 0.54; 95% CI: 0.30-0.97; p = .04) and relapse-free survival (RFS) (aHR: 0.21; 95% CI: 0.12-0.38; p < .001). The 5-year adjusted OS and RFS were 73% and 70% in the allo-SCT cohort, whereas they were 50% and 20% in the non-SCT cohort. Despite the higher non-relapse mortality (aHR: 3.49; 95% CI: 1.17-10.4; p = .03), allo-SCT was significantly associated with a lower relapse rate (aHR: 0.10; 95% CI: 0.05-0.20; p < .001). In addition, allo-SCT was also associated with superior graft-versus-host disease-free, relapse-free survival (aHR: 0.43; 95% CI: 0.25-0.74; p = .002). Propensity score-matched analyses confirmed the results of the multivariate analyses. In patients who achieved CMR within 3 months, allo-SCT in CR1 had superior survival and lower relapse compared with the non-SCT cohort.

Development and evaluation of a rapid one-step high sensitivity real-time quantitative PCR system for minor BCR-ABL (e1a2) test in Philadelphia-positive acute lymphoblastic leukemia (Ph+ ALL).

OBJECTIVE: Minimal residual disease assessment of BCR-ABL messenger ribonucleic acid levels is crucial in Philadelphia chromosome-positive acute lymphoblastic leukemia for prognosis and treatment planning. However, accurately quantifying minor BCR-ABL transcripts, which comprise 70% of Philadelphia chromosome-positive acute lymphoblastic leukemia cases, lacks a national-approved method. METHODS: We developed the "Otsuka" minor BCR-ABLmessenger ribonucleic acid assay kit with exceptional precision (0.00151%). Minor BCR-ABL messenger ribonucleic acid levels were analyzed in 175 adults, 36 children with acute lymphoblastic leukemia and 25 healthy individuals to evaluate the kit's performance. RESULTS: The "Otsuka" kit showed high concordance with a commonly used chimeric gene screening method, indicating reliable detection of positive cases. Quantitative results demonstrated a robust correlation with both a laboratory-developed test and a diagnostic research product. The "Otsuka" kit performs comparably or even surpass to conventional products, providing valuable insights into Philadelphia chromosome-positive acute lymphoblastic leukemia pathology. CONCLUSIONS: The 'Otsuka" minor BCR-ABL messenger ribonucleic acid assay kit exhibits excellent performance in quantifying minor BCR-ABL transcripts in Philadelphia chromosome-positive acute lymphoblastic leukemia patients. Our results align well with established screening methods and show a strong correlation with laboratory-developed tests and diagnostic research products. The "Otsuka" kit holds great promise as a valuable tool for understanding Philadelphia chromosome-positive acute lymphoblastic leukemia pathology and guiding effective treatment strategies.

Venetoclax plus low-dose cytarabine in patients with newly diagnosed acute myeloid leukemia ineligible for intensive chemotherapy: an expanded access study in Japan.

BACKGROUND: In a Phase 3 international clinical trial (VIALE-C), venetoclax plus low-dose cytarabine improved the response rate and overall survival versus placebo plus low-dose cytarabine in patients with newly diagnosed acute myeloid leukemia who were ineligible for intensive chemotherapy. After the enrollment period of VIALE-C ended, we conducted an expanded access study to provide preapproval access to venetoclax in combination with low-dose cytarabine in Japan. METHODS: Previously, untreated patients with acute myeloid leukemia who were ineligible for intensive chemotherapy were enrolled according to the VIALE-C criteria. Patients received venetoclax (600 mg, Days 1-28, 4-day ramp-up in Cycle 1) in 28-day cycles and low-dose cytarabine (20 mg/m2, Days 1-10). All patients took tumor lysis syndrome prophylactic agents and hydration. Safety endpoints were assessed. RESULTS: Fourteen patients were enrolled in this study. The median age was 77.5 years (range = 61-84), with 78.6% over 75 years old. The most common grade ≥ 3 treatment-emergent adverse event was neutropenia (57.1%). Febrile neutropenia was the most frequent serious adverse event (21.4%). One patient developed treatment-related acute kidney injury, leading to discontinuation of treatment. Two patients died because of cardiac failure and disease progression that were judged not related to study treatment. No patients developed tumor lysis syndrome. CONCLUSIONS: The safety outcomes were similar to those in VIALE-C without new safety signals and were well managed with standard medical care. In clinical practice, more patients with severe background disease are expected, in comparison with in VIALE-C, suggesting that it is important to carefully manage and prevent adverse events.

Prospective comparison of 5- and 7-day administration of azacitidine for myelodysplastic syndromes: a JALSG MDS212 trial.

The hypomethylating agent azacitidine (AZA) significantly extends overall survival (OS) in patients with higher risk myelodysplastic syndromes (MDS), when compared with other conventional care regimens, including supportive care and low-dose and intensive chemotherapy. However, the effects of 5- and 7-day treatment schedules of AZA (AZA-5 and AZA-7, respectively) on the OS of MDS patients had not been compared prospectively. We started a phase 3 trial comparing the effects of AZA-7 and AZA-5 on MDS patients with refractory anemia with excess blasts (RAEB) and RAEB in transformation (RAEB-T). However, this trial was prematurely terminated because of poor recruitment. Using all data, there was no significant difference in the OS of patients between AZA-7 (92 patients) and AZA-5 (95 patients), with the 2-year OS rates of AZA-7 and AZA-5 at 36.4% and 25.8%, respectively (P = 0.293). Adverse event profiles were similar between the two groups. Interestingly, data of the centrally diagnosed RAEB and RAEB-T cases showed that AZA-7 significantly prolonged the time to leukemia transformation compared with AZA-5 (P = 0.022), confirmed by multivariate analysis. Although this trial could not provide definite evidence, the results support the use of AZA-7 for RAEB and RAEB-T. (UMIN Clinical Trials Registry UMIN000009633).

Two novel high-risk adult B-cell acute lymphoblastic leukemia subtypes with high expression of CDX2 and IDH1/2 mutations.

The genetic basis of leukemogenesis in adults with B-cell acute lymphoblastic leukemia (B-ALL) is largely unclear, and its clinical outcome remains unsatisfactory. This study aimed to advance the understanding of biological characteristics, improve disease stratification, and identify molecular targets of adult B-ALL. Adolescents and young adults (AYA) (15 to 39 years old, n = 193) and adults (40 to 64 years old, n = 161) with Philadelphia chromosome-negative (Ph-) B-ALL were included in this study. Integrated transcriptomic and genetic analyses were used to classify the cohort into defined subtypes. Of the 323 cases included in the RNA sequencing analysis, 278 (86.1%) were classified into 18 subtypes. The ZNF384 subtype (22.6%) was the most prevalent, with 2 novel subtypes (CDX2-high and IDH1/2-mut) identified among cases not assigned to the established subtypes. The CDX2-high subtype (3.4%) was characterized by high expression of CDX2 and recurrent gain of chromosome 1q. The IDH1/2-mut subtype (1.9%) was defined by IDH1 R132C or IDH2 R140Q mutations with specific transcriptional and high-methylation profiles. Both subtypes showed poor prognosis and were considered inferior prognostic factors independent of clinical parameters. Comparison with a previously reported pediatric B-ALL cohort (n = 1003) showed that the frequencies of these subtypes were significantly higher in AYA/adults than in children. We delineated the genetic and transcriptomic landscape of adult B-ALL and identified 2 novel subtypes that predict poor disease outcomes. Our findings highlight the age-dependent distribution of subtypes, which partially accounts for the prognostic differences between adult and pediatric B-ALL.

Dasatinib-based 2-step induction for adults with Philadelphia chromosome-positive acute lymphoblastic leukemia.

The standard treatment for adults with Philadelphia chromosome-positive (Ph+) acute lymphoblastic leukemia (ALL) in Japan is imatinib-based chemotherapy followed by allogeneic hematopoietic stem cell transplantation (HSCT). However, ∼40% of patients cannot undergo HSCT in their first complete remission (CR1) because of chemotherapy-related toxicities or relapse before HSCT or older age. In this study, we evaluated dasatinib-based 2-step induction with the primary end point of 3-year event-free survival (EFS). The first induction (IND1) was dasatinib plus prednisolone to achieve CR, and IND2 was dasatinib plus intensive chemotherapy to achieve minimal residual disease (MRD) negativity. For patients who achieved CR and had an appropriate donor, HSCT during a consolidation phase later than the first consolidation, which included high-dose methotrexate, was recommended. Patients with pretransplantation MRD positivity were assigned to receive prophylactic dasatinib after HSCT. All 78 eligible patients achieved CR or incomplete CR after IND1, and 52.6% achieved MRD negativity after IND2. Nonrelapse mortality (NRM) was not reported. T315I mutation was detected in all 4 hematological relapses before HSCT. Fifty-eight patients (74.4%) underwent HSCT in CR1, and 44 (75.9%) had negative pretransplantation MRD. At a median follow-up of 4.0 years, 3-year EFS and overall survival were 66.2% (95% confidence interval [CI], 54.4-75.5) and 80.5% (95% CI, 69.7-87.7), respectively. The cumulative incidence of relapse and NRM at 3 years from enrollment were 26.1% and 7.8%, respectively. Dasatinib-based 2-step induction was demonstrated to improve 3-year EFS in Ph+ ALL. This study was registered in the UMIN Clinical Trial Registry as #UMIN000012173.

Venetoclax plus low-dose cytarabine in Japanese patients with untreated acute myeloid leukaemia ineligible for intensive chemotherapy.

BACKGROUND: In a multinational phase 3 trial (VIALE-C), venetoclax plus low-dose cytarabine prolonged overall survival vs placebo plus low-dose cytarabine in patients with newly diagnosed acute myeloid leukaemia ineligible for intensive chemotherapy, although it was not statistically significant. Herein, we assess the benefit of venetoclax plus low-dose cytarabine in the Japanese subgroup of VIALE-C patients (n = 27). METHODS: VIALE-C, a randomized (2:1), double-blind study (NCT03069352), enrolled untreated patients (≥18 years) with acute myeloid leukaemia. Patients received venetoclax (600 mg days 1-28, 4-day ramp-up in cycle 1) or placebo in 28-day cycles with low-dose cytarabine (20 mg/m2 days 1-10). The primary endpoint was median overall survival. RESULTS: In the Japanese subgroup, at a 6-month follow-up from the primary analysis, median overall survival for venetoclax (n = 18) and placebo (n = 9), plus low-dose cytarabine, was 4.7 and 8.1 months, respectively (hazard ratio, 0.928, 95% confidence intervals : 0.399, 2.156). The rate of complete remission plus complete remission with incomplete blood count recovery was higher with venetoclax plus low-dose cytarabine (44.4%) vs placebo plus low-dose cytarabine (11.1%). All patients experienced at least 1 adverse event. The most common grade ≥3 adverse events with venetoclax or placebo, plus low-dose cytarabine, were febrile neutropenia (50.0% vs 44.4%, respectively) and thrombocytopenia (27.8% vs 44.4%, respectively). Serious adverse events were reported in 50.0 and 33.3% of patients in the venetoclax and placebo, plus low-dose cytarabine arms, respectively; pneumonia was the most common (22.2% each). CONCLUSIONS: Limited survival benefit in the Japanese subgroup can be attributed to small patient numbers and to baseline imbalances observed between treatment arms, with more patients in the venetoclax plus low-dose cytarabine arm presenting poor prognostic factors. Venetoclax plus low-dose cytarabine was well tolerated in Japanese patients with acute myeloid leukaemia ineligible for intensive chemotherapy.

A randomized phase 2/3 study of R-CHOP vs CHOP combined with dose-dense rituximab for DLBCL: the JCOG0601 trial.

Rituximab plus cyclophosphamide-doxorubicin-vincristine-prednisone (R-CHOP) is the standard of care for untreated diffuse large B-cell lymphoma (DLBCL). However, the schedule for rituximab administration has not been optimized. To compare standard R-CHOP with CHOP plus dose-dense weekly rituximab (RW-CHOP) in patients with untreated DLBCL, we conducted a phase 2/3 study (JCOG0601, jRCTs031180139). Patients were randomly assigned to R-CHOP (CHOP-21 with 8 doses of rituximab once every 3 weeks [375 mg/m2]) or RW-CHOP (CHOP-21 with 8 doses of weekly rituximab [375 mg/m2]) groups. The primary end point of the phase 2 component was percent complete response (%CR) of the RW-CHOP arm, whereas that of the phase 3 component was progression-free survival (PFS). Between December 2007 and December 2014, 421 untreated patients were randomly assigned to R-CHOP (213 patients) or RW-CHOP (208 patients). The %CR in the RW-CHOP arm was 85.3% and therefore met the prespecified decision criteria for the phase 2 component. With a median follow-up of 63.4 months, the 3-year PFS and overall survival were 79.2% and 88.7% in the R-CHOP arm and 80.3% and 90.4% in the RW-CHOP arm, respectively. There was no significant difference in PFS (hazard ratio, 0.95; 90.6% confidence interval, 0.68-1.31). Although the safety profile and efficacy of RW-CHOP was comparable with R-CHOP and its tolerability was acceptable, weekly rituximab in combination with CHOP during the early treatment period did not improve PFS in untreated patients with DLBCL. This trial was registered at jrct.niph.go.jp as #jRCTs031180139.

Successful bridge therapy of gilteritinib to cord blood transplantation in relapsed acute myeloid leukemia after bone marrow transplantation.

The FMS-related tyrosine kinase 3 (FLT3) internal tandem duplication mutations (FLT3-ITD) positive acute myeloid leukemia (AML) is a disease with a dismal outcome. Gilteritinib is a second-generation FLT3 inhibitor with activity against ITD and high affinity toward the FLT3 receptor, thereby showing therapeutic potential for relapsed/refractory FLT3-mutated AML. Bone marrow transplantation (BMT) from a human leukocyte antigen (HLA) identical sibling donor was performed in a 38-year-old Japanese male with FLT3-ITD positive AML. Neutrophil engraftment (>0.5 × 109/L) was achieved on day 16, and bone marrow remission was revealed on day 32. The patient's AML relapsed hematologically four months after BMT and was resistant to salvage chemotherapy. Gilteritinib was administered and the patient achieved non-remission but 'stable disease' status according to the response criteria. During administration, liver damage was observed but controllable. The patient received cord blood transplantation (CBT) as the second hematopoietic stem cell transplantation (HSCT) three months after relapse and achieved second remission. There was no evidence of recurrence of AML four months after CBT. This case demonstrates that gilteritinib can control FLT3-ITD positive AML that relapsed early after initial HSCT and can bridge to second HSCT.

[Treatments for Philadelphia chromosome-positive acute lymphoblastic leukemia in the tyrosine kinase inhibitor era].

The introduction of imatinib (IM) has led to a paradigm shift in the treatment strategy for Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ALL). After introducing IM, second- and third-generation tyrosine kinase inhibitors (TKIs), which have stronger BCR-ABL1 inhibitory activity than IM, have appeared and their therapeutic results are beginning to be reported. However, to date, no comparison study between individual TKI and the current treatment strategy for Ph + ALL has been performed considering either a TKI-based regimen in induction followed by combination chemotherapy with a TKI or allogeneic hematopoietic stem cell transplantation (alloSCT). In the case of treating with ponatinib, it was suggested that the inclusion of alloSCT into the treatment strategy could be avoided. Because alloSCT has an appreciable treatment-related mortality rate and an upper age limit, the treatment strategy without alloSCT may remain mainstream in the future. Chemotherapy-free treatments, such as a TKI plus a monoclonal antibody or immunotherapy, are also expected to gain traction an alternate strategy and are now under investigation.

Predictors of early death, serious hemorrhage, and differentiation syndrome in Japanese patients with acute promyelocytic leukemia.

Significant advancements have been achieved with regard to the outcomes of acute promyelocytic leukemia (APL) patients through the introduction of all-trans retinoic acid; however, early hemorrhagic death and differentiation syndrome remain the major causes of remission induction failure in patients with APL. To investigate early death, serious hemorrhage, and differentiation syndrome during remission induction therapy in terms of incidence, risk factors, influence on outcomes, and prophylactic effects of several new anticoagulants, the results of 344 patients enrolled in the Acute Promyelocytic Leukemia 204 study conducted by the Japan Adult Leukemia Study Group were analyzed. Early death was observed in 16 patients (4.7%), of whom 14 had serious hemorrhage and 2 had differentiation syndrome. Serious hemorrhage and differentiation syndrome of grade 2 or higher were observed in 21 and 54 patients, respectively. Patients who achieved complete remission had a 7-year disease-free survival of 84.8% if they did not experience serious hemorrhage and 40.0% if they experienced serious hemorrhage during remission induction therapy (P = 0.001). Risk factor analyses showed that higher white blood cell count was associated with early death, higher white blood cell count and lower platelet count with serious hemorrhage, and leukocytosis during induction therapy and higher body surface area with differentiation syndrome. In conclusion, these results indicate that patients with such high-risk features may benefit from more intensive supportive care. The hemorrhagic risk was not relieved by the introduction of new anticoagulants. Further studies are required to establish the predictive impact of body surface area on differentiation syndrome. This trial is registered with UMIN-CTR as C000000154 on September 13, 2005.

Impact of CD56 Continuously Recognizable as Prognostic Value of Acute Promyelocytic Leukemia: Results of Multivariate Analyses in the Japan Adult Leukemia Study Group (JALSG)-APL204 Study and a Review of the Literature.

BACKGROUND: After long-term analysis of the JALSG-APL204 study we recently reported that maintenance therapy with tamibarotene was more effective than all-trans retinoic acid (ATRA) by reducing relapse in APL patients. Here, the clinical significance of other important prognostic factors was evaluated with multivariate analyses. PATIENTS AND METHODS: Newly diagnosed acute promyelocytic leukemia (APL) patients were registered with the study. Induction was composed of ATRA and chemotherapy. Patients who achieved molecular remission after consolidation were randomly assigned to maintenance with tamibarotene or ATRA. RESULTS: Of the 344 eligible patients, 319 (93%) achieved complete remission (CR). After completing consolidation, 269 patients underwent maintenance random assignment-135 to ATRA, and 134 to tamibarotene. By multivariate analysis, overexpression of CD56 in blast was an independent unfavorable prognostic factor for relapse-free survival (RFS) (p = 0.006) together with more than 10.0 × 109/L WBC counts (p = 0.001) and the ATRA arm in maintenance (p = 0.028). Of all phenotypes, CD56 was related most clearly to an unfavorable prognosis. The CR rate, mortality rate during induction and overall survival of CD56+ APL were not significantly different compared with CD56- APL. CD56 is continuously an independent unfavorable prognostic factor for RFS in APL patients treated with ATRA and chemotherapy followed by ATRA or tamibarotene maintenance therapy.

Prospective evaluation of prognostic impact of KIT mutations on acute myeloid leukemia with RUNX1-RUNX1T1 and CBFB-MYH11.

The prognostic impact of KIT mutation on core-binding factor acute myeloid leukemia (CBF-AML) remains controversial. We registered 199 newly diagnosed de novo CBF-AML patients, aged 16 to 64 years, who achieved complete remission. They received 3 courses of high-dose cytarabine therapy and no further treatment until hematological relapse. Mutations in exons 8, 10-11, and 17 of the KIT gene were analyzed. Furthermore, we analyzed mutations in 56 genes that are frequently identified in myeloid malignancies and evaluated minimal residual disease (MRD). The primary end point was relapse-free survival (RFS) according to KIT mutations. The RFS in KIT-mutated patients was inferior to that in unmutated patients (hazard ratio, 1.92; 95% confidence interval, 1.23-3.00; P = .003). Based on subgroup analysis, KIT mutations had a prognostic impact in patients with RUNX1-RUNX1T1, but not in those with CBFB-MYH11, and only exon 17 mutation had a significant prognostic impact. Multivariate Cox regression analysis with stepwise selection revealed that the KIT exon 17 mutation and the presence of extramedullary tumors in patients with RUNX1-RUNX1T1, and loss of chromosome X or Y and NRAS mutation in patients with CBFB-MYH11 were poor prognostic factors for RFS. MRD was evaluated in 112 patients, and it was associated with a poorer RFS in the patients with CBFB-MYH11, but not in those with RUNX1-RUNX1T1. These results suggested that it is necessary to separately evaluate AML with RUNX1-RUNX1T1 or CBFB-MYH11 according to appropriate prognostic factors. This study was registered at www.umin.ac.jp/ctr/ as #UMIN000003434.

Plasma exchange combined with bortezomib-based chemotherapy is effective for early renal recovery in a patient with IgD-λ type multiple myeloma.

The immunoglobulin (Ig) D type is a rare variant of multiple myeloma (MM), that accounts for 1-2% of all cases. Compared to the more common types of MM, IgD MM is known to have more severe symptoms at presentation, and a poorer prognosis. A woman was admitted to our hospital for severe acute kidney disease and disorder (AKD) and back pain, and was started on hemodialysis. The renal biopsy revealed light chain cast nephropathy. She was diagnosed with IgD-λ MM based on Bence-Jones protein expression and high IgD serum levels, and started bortezomib therapy with plasma exchange (PE). After three sessions of PE, the serum free light chain levels decreased by 92%, and she was withdrawn from dialysis. The patient underwent autologous transplantation and is still in remission, demonstrating the benefits of a bortezomib-based regimen in combination with PE for IgD MM with AKD.

[Outcomes of primary central nervous system lymphoma patients treated with high-dose methotrexate and rituximab].

Primary central nervous system lymphoma (PCNSL) is a rare, aggressive type of non-Hodgkin lymphoma with a poor prognosis and no defined optimal therapeutic strategies. We retrospectively analyzed the survival of six PCNSL patients who were treated with high-dose methotrexate (HDMTX) -based chemotherapy combined with rituximab. The median age at diagnosis was 71 (range, 54-75) years, and the ECOG performance status was ≥3 in four patients. The histopathological findings revealed that all patients had diffuse large B-cell lymphoma. Objective response was obtained in all patients (five, complete response; one, partial response). Three patients had severe non-hematological toxicities: one had pulmonary thromboembolism, one had sepsis, and one developed acute epididymitis. However, each patient recovered and their symptoms could be managed. The median follow-up was 28.8 (range, 13.4-65.5) months. Five patients were still alive and disease-free, and one patient relapsed 62.2 months after the diagnosis. Therefore, the addition of rituximab to HDMTX may improve outcomes. Further clinical investigation is necessary to establish standardized initial therapies for PCNSL, particularly in elderly patients.

Tamibarotene maintenance improved relapse-free survival of acute promyelocytic leukemia: a final result of prospective, randomized, JALSG-APL204 study.

Between April 2004 and December 2010, we conducted a prospective randomized controlled study comparing tamibarotene with all-trans retinoic acid (ATRA) in the maintenance therapy of newly diagnosed acute promyelocytic leukemia (APL), and here report the final results of this study with a median follow-up of 7.3 years. Of 344 eligible patients who had received ATRA and chemotherapy, 319 (93%) achieved complete remission (CR). After completion of three courses of consolidation chemotherapy, 269 patients in molecular remission underwent maintenance randomization, 135 to ATRA (45 mg/m2 daily), and 134 to tamibarotene (6 mg/m2 daily) for 14 days every 3 months for 2 years. The primary endpoint was relapse-free survival (RFS). The 7-year RFS was 84% in the ATRA arm and 93% in the tamibarotene arm (p = 0.027, HR = 0.44, 95% CI, 0.21 to 0.93). The difference was prominent in high-risk patients with initial leukocytes ≥ 10.0 × 109/L (62% vs. 89%; p = 0.034). Tamibarotene was significantly superior to ATRA by decreasing relapse in high-risk patients. Overall survival after randomization did not differ (96% vs. 97%; p = 0.520). Secondary hematopoietic disorders developed in nine patients, secondary malignancies in 11, and grade 3 or more late cardiac comorbidities in three. These late complications did not differ between the two arms.

[A novel quantitative JAK2V617F detection kit: prospective clinical performance study comparing MPN patients and healthy subjects].

The JAK2V617F mutation is the commonest major genetic mutation of myeloproliferative neoplasms (MPNs) and has been defined in the WHO diagnostic criteria for MPNs. However, there is still no approved in vitro diagnostic test kit available in Japan. We evaluated a JAK2V617F allele quantification kit (test method) in a prospective, multicenter clinical performance study involving patients with MPNs who were diagnosed with polycythemia vera, essential thrombocythemia, and primary myelofibrosis; healthy volunteers were also included in the analysis. Good correlation was observed between the allele burden determined using the test method vs. that determined using next-generation sequencing (NGS) in the patient group (r=0.998, y=1.071x-0.069; n=156). Furthermore, all allele burdens in the healthy group (n=54) were below the lower limit of the measurement range of the test method (0.042%). Our results confirmed that the test method could quantitatively measure the JAK2V617F allele burden in patients with MPN. Thus, the novel JAK2V617F allele quantification kit can be considered useful for the diagnosis of MPNs.

Final analysis of the JALSG Ph+ALL202 study: tyrosine kinase inhibitor-combined chemotherapy for Ph+ALL.

The Japan Adult Leukemia Study Group (JALSG) Ph+ALL202 study reported a high complete remission (CR) rate for Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ALL) patients treated with imatinib-combined chemotherapy. However, the long-term treatment efficacy remains uncertain. Here, we report a final analysis of the JALSG Ph+ALL202 study. The outcomes were compared with those of the JALSG ALL93 and ALL97 studies, which were conducted in the pre-imatinib era. Ninety-nine newly diagnosed Ph+ALL patients were enrolled in Ph+ALL202 (median age, 45 years; median follow-up, 4.5 years). CR was achieved in 96/99 (97%) patients. Fifty-nine of these 96 patients (61%) underwent allogeneic hematopoietic stem cell transplantation (allo-HSCT) in their first CR (CR1). The 5-year overall and disease-free survival (DFS) rates were 50 and 43%, respectively, which were significantly higher compared to those in the pre-imatinib era (15 and 19%, respectively). Multivariate analysis revealed that imatinib administration, allo-HSCT in CR1, and a white blood cell count < 30 × 109/L were favorable independent prognostic factors for long-term DFS. Improved odds of receiving allo-HSCT and a lower relapse rate leaded to good long-term outcomes. The 3-year DFS tended to be higher in PCR-negative than that in PCR-positive patients (29 vs. 14%) in the non-HSCT patients, and this tendency was also seen in the allo-HSCT patients (59 vs. 50%). The higher rate of CR upon imatinib use may have contributed to these improvements.