Characteristics of chronic lymphocytic leukemia in Japan: Comprehensive analysis of the CLLRSG-01 study.

Chronic lymphocytic leukemia (CLL) is rare in Japan. We conducted the nationwide, prospective observational study CLLRSG-01 to clarify the current state of CLL in Japan and to make accurate international comparisons by preparing naturally air-dried smears like those used in other countries. Of the 201 untreated patients enrolled and evaluated, 119 were diagnosed with CLL and 82 with non-CLL mature B-cell neoplasms, based on the WHO classification. Of the 119 CLL patients, 90 were classified as typical and 29 as atypical according to FAB classification morphology, with the proportion of atypical CLL consistent with reports from other countries. Immunophenotypic analyses by flow cytometry showed that 55% of Japanese CLL patients had a Matutes score of 4 or higher, which is lower than the rate of about 90% in Europeans. Mutated IGHV was identified in 80% of Japanese CLL patients, which is a higher rate than in Western patients. The most frequent IGHV gene was VH3-30 (15%), followed by VH3-23 (12%) and VH4-34 (10%). VH1-69, the most common gene in Western countries, was identified in only one patient. These results indicate that the pattern of immunophenotypes and IGHV gene usage in Japanese CLL patients differs from that in Western patients.

Clinicopathological comparison between PTCL-TBX21 and PTCL-GATA3 in Japanese patients.

AIM: Peripheral T-cell lymphoma not otherwise specified (PTCL-NOS) is a heterogeneous disease that can be classified into the PTCL-TBX21 and PTCL-GATA3 subtypes. METHODS: In this study, we compared the clinicopathological features of PTCL-NOS in a Japanese cohort, classified using an IHC algorithm. RESULTS: One hundred patients with PTCL-NOS were categorized as having PTCL-TBX21 (n = 55), PTCL-GATA3 (n = 24), or PTCL-unclassified (n = 21). When comparing PTCL-TBX21 and PTCL-GATA3, PTCL-TBX21 showed significantly lower CD4 positivity (p = 0.047), lower counts of high endothelial venules (p = 0.032), and a tendency for a better response to initial treatment (p = 0.088). Gene expression analysis using the nCounter system showed higher expression of tumor immunity-related genes, such as PD-L1, LAG3, and IDO1, in PTCL-TBX21 than in PTCL-GATA3. PTCL-GATA3 had significantly worse overall survival (OS) than those with PTCL-TBX21 (p = 0.047), although a similar tendency was observed for progression-free survival (PFS) (p = 0.064). PTCL-GATA3 was a prognostic factor for OS in univariate analysis (HR 2.02; 95% CI, 1.09-3.77; p = 0.027), although multivariate analysis did not show significance (HR 2.07; 95% CI, 0.93-4.61; p = 0.074). In the PFS analysis, PTCL-GATA3 was an independent prognostic factor by univariate analysis (HR 1.96; 95% CI, 1.08-3.56; p = 0.027) and multivariate analysis (HR 2.34; 95% CI, 1.07-5.11; p = 0.032). CONCLUSION: The classification of PTCL-NOS into PTCL-TBX21 and PTCL-GATA3 is useful for predicting the prognosis of Japanese patients and stratifying the administration of tumor immune checkpoint inhibitors in clinical practice.

Cord blood transplantation for adult mature lymphoid neoplasms in Europe and Japan.

ABSTRACT: To clarify the different characteristics and prognostic factors of cord blood transplantation (CBT) in adult patients with lymphoid neoplasms in Europe and Japan, we conducted a collaborative study. Patients aged 18-75 years receiving their first CBT (Europe: single CBT, n = 192; double CBT, n = 304; Japan: single CBT, n = 1150) in 2000-2017 were analyzed. Fewer patients with Hodgkin lymphoma (Europe vs Japan, 26% vs 5%), and older patients (≥50 years) (39% vs 59%) with a higher refined disease risk index (rDRI) (high-very high: 49% vs 14%) were included in the Japanese registry. High-very high rDRI was associated with inferior overall survival (OS) (vs low rDRI, Europe: hazard ratio [HR], 1.87; P = .001; Japan: HR, 2.34; P < .001) with higher progression/relapse risks. Total body irradiation (TBI)-containing conditioning contributed to superior OS both in Europe (vs TBI-reduced-intensity conditioning [RIC], non-TBI-RIC: HR, 1.93; P < .001; non-TBI-Myeloablative conditioning [MAC]: HR, 1.90; P = .003) and Japan (non-TBI-RIC: HR, 1.71; P < .001; non-TBI-MAC: HR 1.50, P = .007). The impact of HLA mismatches (≥2) on OS differed (Europe: HR, 1.52; P = .007; Japan: HR, 1.18; P = .107). CBT for lymphoid neoplasms, especially in those with high rDRI showed poor outcomes despite all the different characteristics in both registries. TBI should be considered in conditioning regimens to improve these outcomes. The different impacts of HLA mismatches call attention to the fundamental differences among these populations.

Outcomes of allogeneic hematopoietic stem cell transplantation for relapsed or refractory diffuse large B-cell lymphoma.

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is a currative treatment modality for diffuse large B-cell lymphoma (DLBCL) because of the intrinsic graft-versus-lymphoma effect. However, limited information is available regarding which patients with relapsed or refractory DLBCL are likely to benefit from allo-HSCT. We retrospectively analyzed data from 1268 DLBCL patients who received allo-HSCT. The overall survival and progression-free survival (PFS) rates were 30.3% and 21.6% at 3 years, respectively. Multivariate analysis revealed that stable or progressive disease at transplantation, male patient, poorer performance status at transplantation, and shorter intervals from previous transplantation were associated independently with a lower PFS. Four prognostic factors were used to construct a prognostic index for PFS, predicting 3-year PFS of 55.4%, 43.7%, 20.4% and 6.6%, respectively. The prognostic model predicted relapse rates following allo-HSCT accordingly (P < 0.0001), whereas did not predict transplantation-related mortality (P = 0.249). The prognostic index can identify a subgroup of DLBCL patients who benefit from allo-HSCT and it is worthwhile to evaluate whether this model is also applicable to patients undergoing allo-HSCT in cases of relapse after chimeric antigen receptor engineered T-cell therapy, although the application of allo-HSCT has been declining with the increase of novel immunotherapies.

Outcomes in human T-cell leukemia virus type I carriers after hematopoietic stem cell transplantation for diseases other than adult T cell leukemia/lymphoma: a Japanese national survey.

Background: Human T-cell leukemia virus type I (HTLV-1) is a retrovirus known to cause adult T-cell leukemia/lymphoma (ATL). There are few reports on hematopoietic stem cell transplantation (HSCT) for HTLV-1 carriers with diseases other than ATL. Methods: A total of 25,839 patients (24,399 adults and 1440 children) with pre-transplant HTLV-1 serostatus information recorded in the Japanese National Survey Database who had undergone their first HSCT were analyzed. We investigated the overall survival (OS), transplant-related mortality (TRM), and disease-related mortality (DRM) after HSCT in relation to HTLV-1 serologic status. Findings: Three hundred and forty-eight patients were HTLV-1 antibody carriers. The number of HTLV-1 carriers and noncarriers among adult patients who received allogeneic HSCT (allo-HSCT) or autologous HSCT (auto-HSCT) was 237/15,777 and 95/8920, respectively, and was 16/1424 among pediatric patients who received allo-HSCT. No pediatric HTLV-1 carrier recipients undergoing auto-HSCT were identified. There were no significant differences between HTLV-1 carriers and non-carriers regarding stem cell source, disease risk, or HCT-CI score prior to allo-HSCT. Multivariate analysis of OS (P = 0.020) and TRM (P = 0.017) in adult patients showed that HTLV-1 positive status was a significant prognostic factor. In children, TRM was significantly higher (P = 0.019), but OS was not significantly different. In adult patients who underwent auto-HSCT, HTLV-1 positive status was not a significant prognostic factor. In adult allo-HSCT patients, cytomegalovirus reactivation was significantly more common in HTLV-1 carriers (P = 0.001). Interpretation: HTLV-1 antibody positivity was shown to have a poor prognosis in OS and TRM after allo-HSCT in adult patients and in TRM after allo-HSCT in pediatric patients. Funding: This work was supported in part by the practical research programs of the Japan Agency for Medical Research and Development (AMED) under grant number 17ck0106342h0001.

[The correct way to read and understand published clinical trial results].

Correct interpretation of clinical trial results is important. Overall survival was once considered the primary endpoint for neoplastic disease, but surrogate endpoints are increasingly being used for diseases whose prognosis has improved. This is due to the longer trial duration required to obtain conclusions and to poor statistical power. Clinical decision-making in practice is also shifting to using these surrogate endpoints. In clinical trials, eligibility criteria are set to obtain differences between arms. However, this does not mean that results should only be applied to eligible populations, as it is not realistic to conduct a clinical trial in patients with all possible characteristics. Rather, results should be applied to patients who do not meet the eligibility criteria, with careful consideration. A single clinical trial often presents the results of many subgroup analyses, but the main conclusion should not be judged differently by subgroup. The purpose of subgroup analysis is to find potential confounders that interact with the conclusion, and results of subgroup analysis should not be overestimated. Non-inferiority trials have become increasingly common in recent years, and their importance is not limited to demonstrating the non-inferiority of the primary endpoint. Specifically, they are also important for understanding the benefits in the experimental arm outside those in primary analysis. Some secondary endpoints are very important for making conclusions about these benefits.

Impact of GVHD on lymphoma progression: Nationwide study from Japanese Society for Transplantation and Cellular Therapy.

The graft-versus-lymphoma (GVL) effect and its association with acute and chronic GVHD (aGVHD, cGVHD) has not been comprehensively elucidated. We retrospectively analysed 2204 Japanese patients with non-Hodgkin lymphomas (NHLs; indolent B-NHLs, n = 689; aggressive B-NHLs, n = 720; mature T/NK-NHLs, n = 795) receiving a first allo-HSCT in 2003-2017. Pre-transplant lymphoma control showed complete response (CR) in 759 and non-CR in 1445. We assessed the impact of aGVHD/cGVHD on lymphoma progression and other outcomes. Although aGVHD/cGVHD showed no statistical impact on lymphoma progression in the overall cohort, their impact was clear in certain groups: Grade I-II aGVHD in CR patients (HR, 0.63; 95% CI, 0.43-0.91), especially in mature T/NK-NHL (HR, 0.46; 95% CI, 0.26-0.83) and extensive cGVHD in patients with mature aggressive B-NHLs (HR, 0.55; 95% CI, 0.31-0.97). In total, limited cGVHD was associated with superior survivals (progression-free survival: HR, 0.71; 95% CI, 0.56-0.90), whereas severe GVHDs showed negative impacts on them. Our results support the presence of GVL effects differentially associated with GVHD in different lymphoma subtypes/controls. Meanwhile, it was also suggested that we should manage GVHDs within a limited activity, considering the negative impact of severe GVHDs. As pre-transplant lymphoma control remains a strong factor influencing transplant outcomes, improving its management is an important issue to be addressed.

Clinical characteristics of late-onset interstitial pneumonia after allogeneic hematopoietic stem cell transplantation.

Non-infectious pulmonary complications after allogeneic hematopoietic stem cell transplantation (HSCT) remain fatal. In particular, information regarding late-onset interstitial lung disease predominantly including organizing pneumonia and interstitial pneumonia (IP) is limited. A retrospective nationwide survey was conducted using data collected from the Japanese transplant outcome registry database from 2005 to 2010. This study focused on patients (n = 73) with IP diagnosed after day 90 post-HSCT. A total of 69 (94.5%) patients were treated with systemic steroids, and 34 (46.6%) experienced improvement. The presence of chronic graft-versus-host disease at the onset of IP was significantly associated with non-improvement of symptoms (odds ratio [OR] 0.35). At the time of last follow-up (median, 1471 days), 26 patients were alive. Of the 47 deaths, 32 (68%) were due to IP. The 3-year overall survival (OS) and non-relapse mortality (NRM) rates were 38.8% and 51.8%, respectively. In the multivariate analysis, the predictive factors for OS were comorbidities at IP onset (hazard ratio [HR]: 2.19) and performance status (PS) score of 2-4 (HR 2.77). Furthermore, cytomegalovirus reactivation requiring early intervention (HR 2.04), PS score of 2-4 (HR 2.63), and comorbidities at IP onset (HR 2.90) were also significantly associated with increased risk of NRM.

Clinical characteristics and risk factors of pneumococcal diseases in recipients of allogeneic hematopoietic stem cell transplants in the late phase: A retrospective registry study.

Pneumococcal diseases are one of the most important infectious complications in the late period following allogeneic hematopoietic stem cell transplantation (allo-HSCT). The importance of long-term follow-up care is increasing, as the number of long-term survivors following allo-HSCT increases, but there has been a dearth of research specifically focusing on pneumococcal diseases during the late post-transplant period (day >100). Using a transplant registry database between January 1, 2001 and December 31, 2011, we aimed to assess the clinical spectrum and risk factors for pneumococcal diseases in the late post-transplant period. Among the 22,514 recipients who received allo-HSCT over an 11-year period and could be followed for ≥100 days, 43 patients developed 49 episodes of pneumococcal diseases. Six of the 43 patients died from pneumococcal diseases, and four of these six patients died within a week, despite having undergone allo-HSCT two or more years ago. A history of chronic graft-versus-host disease (odds ratio [OR], 2.31; 95% confidence interval [CI], 1.15-4.66; P = 0.02), viral infection (OR, 3.38; 95% CI, 1.70-6.72; P < 0.01), and complete remission of the underlying disease at the time of transplantation (OR, 2.38; 95%CI, 1.10-5.14; P = 0.03) were identified as risk factors. Given the risk of sudden death and the high mortality rate, attention should be paid to pneumococcal diseases in providing long-term follow-up care, even several years after allo-HSCT.

Diagnosis and management of rare paediatric Non-Hodgkin lymphoma.

Mature B-cell lymphomas, (B- or T-cell) lymphoblastic lymphomas (LBL), and anaplastic large cell lymphoma (ALCL) correspond to about 90% of all non-Hodgkin lymphoma (NHL) cases occurring in children and adolescents. The remaining 10% encompass a complex group of entities characterized by low/very low incidences, paucity of knowledge in terms of underlying biology in comparison to their adult counterparts, and consequent lack of standardization of care, information on clinical therapeutic efficacy and long-term survival. At the Seventh International Symposium on Childhood, Adolescent and Young Adult NHL, organized on October 20-23, 2022, in New York City, New York, US, we had the opportunity to discuss clinical, pathogenetic, diagnostic, and treatment aspects of certain subtypes of rare B- or T-cell NHL and they will be the topic of this review.

Efficacy and safety of omalizumab in adult patients with wheat-dependent exercise-induced anaphylaxis: Reduction of in vitro basophil activation and allergic reaction to wheat.

BACKGROUND: In patients with wheat-dependent exercise-induced anaphylaxis (WDEIA), anaphylactic shock occurs frequently, therefore avoidance of wheat products is recommended. We aimed to evaluate efficacy and safety of long-term omalizumab treatment for adult patients with WDEIA. METHODS: In this phase 2, multicentre single-arm trial, 20 adult patients with WDEIA were enrolled (UMIN 000019250). All patients were administered 150-600 mg of omalizumab subcutaneously and evaluations (basophil activation and blood examination) were performed at regular intervals during administration period (0-48 weeks) and observation period (48-68 weeks). Primary endpoint was proportion of the patients who achieved a basophil activation rate below 10% with fractionated wheat preparations, and secondary endpoint was proportion of the patients with no allergic reactions after wheat products ingestion. RESULTS: During the omalizumab treatment, more than 80% of the patients achieved the basophil activation rate less than 10% against all fractionated wheat preparations, and 68.8% of the patients who achieved the primary endpoint experienced no allergic reaction. During the observation period, the proportion of the patients who achieved a basophil activation rate below 10% decreased gradually, and the proportion of patients with positive allergic reactions increased gradually thereafter and reached maximum of 46.7%. Severe adverse events were not observed during the study. CONCLUSIONS: Long-term omalizumab treatment is safe and effective for adult patients with WDEIA when assessed by basophil activation rate with wheat allergens as well as allergic reactions after lifting of restrictions on wheat intake. However, this is not enough to achieve desensitization.

Clinical outcomes of second-generation tyrosine kinase inhibitors versus imatinib in older patients with CML.

Age and comorbidities are important factors to be considered in the selection of tyrosine kinase inhibitors (TKIs) for first-line treatment in patients with chronic myeloid leukemia in chronic phase (CML-CP). However, it is yet unclear whether TKI selection, particularly, imatinib versus second-generation TKIs (2GTKIs), impacts treatment outcomes in the clinical practice. To address this, we compared the clinical outcomes of prospectively registered 452 patients with CML-CP treated with imatinib and 2GTKIs, taking into consideration their age and/or comorbidities. A total of 136 patients (30.1%) were classified into an older cohort (≥65 years) and 316 (69.9%) into a younger cohort (18-64 years). The TKI selection did not vary based on age (70.6% received 2GTKIs in the younger cohort and 66.2% in the older cohort). The median follow-up period was 5.4 years. Treatment responses including the cumulative incidence of deep molecular response (BCR-ABL1 international scale ≤0.0032%) at any time were similar between the two age cohorts regardless of the type of TKI. The 5-year overall survival (OS) in the older cohort was lower than that in the younger cohort (95.9% vs 83.8%; p < 0.0001), whereas the 5-year OS in patients treated with 2GTKIs was not influenced by age factors and comorbidities. Therefore, our results suggest that the selection of 2GTKIs as first-line treatment is an effective option for both younger and older CML-CP patients with or without comorbidities. This trial was registered at UMIN-CTR as 00003581.

Long-term outcomes and central nervous system relapse in extranodal natural killer/T-cell lymphoma.

To elucidate the long-term outcomes of non-anthracycline-containing therapies and central nervous system (CNS) events in patients with extranodal NK/T-cell lymphoma, nasal type (ENKTL), the clinical data of 313 patients with ENKTL diagnosed between 2000 and 2013 in a nationwide retrospective study in Japan were updated and analyzed. At a median follow-up of 8.4 years, the 5-year overall survival (OS) and progression-free survival (PFS) were 71% and 64%, respectively, in 140 localized ENKTL patients who received radiotherapy-dexamethasone, etoposide, ifosfamide, and carboplatin (RT-DeVIC) in clinical practice. Nine (6.4%) patients experienced second malignancies. In 155 localized ENKTL patients treated with RT-DeVIC, 10 (6.5%) experienced CNS relapse (median, 12.8 months after diagnosis). In five of them, the events were confined to the CNS. Nine of the 10 patients who experienced CNS relapse died within 1 year after CNS relapse. Multivariate analysis identified gingival (hazard ratio [HR], 54.35; 95% confidence interval [CI], 8.60-343.35) and paranasal involvement (HR, 7.42; 95% CI, 1.78-30.89) as independent risk factors for CNS relapse. In 80 advanced ENKTL patients, 18 received steroid (dexamethasone), methotrexate, ifosfamide, L-asparaginase, and etoposide (SMILE) chemotherapy as first-line treatment. Patients who received SMILE as their first-line treatment tended to have better OS than those who did not (p = 0.071). Six (7.5%) advanced ENKTL patients experienced isolated CNS relapse (median, 2.6 months after diagnosis) and died within 4 months of relapse. No second malignancies were documented in advanced ENKTL patients. In the entire cohort, the median OS after first relapse or progression was 4.6 months. 12 patients who survived 5 years after PFS events were disease-free at the last follow-up. Of those, 11 (92%) underwent hematopoietic stem cell transplantation. Our 8-year follow-up revealed the long-term efficacy and safety of RT-DeVIC and SMILE. The risk of CNS relapse is an important consideration in advanced ENKTL.

Case of Pulmonary Extramedullary Hematopoiesis Responding to Ruxolitinib.

We report a case of 43-year-old woman diagnosed with essential thrombocythemia in 1992. She was diagnosed with secondary myelofibrosis in 2011. Later, she suffered mild dyspnea, which gradually worsened. She was admitted to our hospital to evaluate the cause in 2014. Chest computed tomography showed ground-glass opacity (GGO) in the lungs. A lung biopsy revealed various hematopoietic cells, including abnormal megakaryocytes, infiltrating the alveolar septum, suggesting pulmonary extramedullary hematopoiesis. She was successfully treated by ruxolitinib and her disease is well controlled for more than 7 years. To keep this phenomenon in mind when see the patients with dyspnea is important.

Lymphoma during pregnancy in Japan: a multicenter retrospective cohort study.

OBJECTIVE: This study was conducted to characterize lymphoma occurring during pregnancy and to investigate the outcomes of the patients and the fetuses. METHODS: Clinical data were gathered retrospectively from 29 patients at 13 participating institutions, and data from 28 eligible patients were analyzed. RESULTS: Six (21%) patients had Hodgkin lymphoma (HL) and 22 (79%) patients had non-Hodgkin lymphoma (NHL). All patients with HL presented with lymphadenopathy, but 15 (68%) of the 22 patients with NHL presented with extranodal sites only. At the median follow-up period of 1325 (range 6-4461) days, the 5-year overall survival rate was 63% for patients with NHL and 100% for patients with HL. Three of the 13 patients who received chemotherapy during pregnancy (23%) developed Pneumocystis jiroveci pneumonia (PCP). There was 1 intrauterine fetal death, 1 spontaneous abortion in the first trimester, and 15 (54%) preterm births. CONCLUSION: This study showed a higher proportion of NHL than HL during pregnancy in Japan, which was inconsistent with the proportions observed in Western countries. The high incidence of maternal PCP and preterm birth suggested the need for improvements in our management of lymphoma during pregnancy.

Risk factors and prognosis of non-infectious pulmonary complications after allogeneic hematopoietic stem cell transplantation.

Non-infectious pulmonary complications (NIPCs) following allogeneic hematopoietic stem cell transplantation (HSCT) are relatively rare, but frequently fatal. This study investigated the pre-transplant risk factors for developing NIPCs using Japanese transplant registry database entries from 2001 to 2009. Among 13,573 eligible patients, 535 experienced NIPCs (3.9%). Multivariate analysis identified high recipient age (60 + years: HR 1.85, P = 0.003), HLA mismatch (HR 1.61, P < 0.001), female to male HSCT (HR 1.54, P < 0.001), and unrelated bone marrow transplantation (UR-BMT) (HR 3.88, P < 0.001) as significantly associated with an increased risk of NIPCs. In contrast, a non-total body irradiation (TBI) regimen with reduced intensity conditioning (RIC) were associated with a decreased risk of NIPCs compared with a cyclophosphamide (CY) + TBI regimen (busulfan + CY: HR 0.67, P = 0.009, other non-TBI: HR 0.46, P < 0.001), fludarabine-based RIC (HR 0.52, P < 0.001), and other RIC (HR 0.42, P = 0.003). The mortality rate was significantly worse for patients with NIPCs than those without (HR 1.54, 71 P < 0.001). This large-scale retrospective study suggests that both allo-reactions to donor cells and conditioning regimen toxicity contributed to NIPCs following HSCT.

Total body irradiation-containing conditioning regimens without antithymocyte globulin in adults with aplastic anemia undergoing umbilical cord blood transplantation.

Thus far, there have been no large cohort studies on total body irradiation (TBI)-containing conditioning regimens without antithymocyte globulin (ATG) in adults with aplastic anemia (AA) undergoing umbilical cord blood (UCB) transplantation (UCBT). We retrospectively analyzed 115 adults with idiopathic AA undergoing UCBT using TBI-containing reduced-intensity conditioning (RIC) regimens without ATG between 2000 and 2018 on behalf of the Adult Aplastic Anemia Working Group of the Japanese Society for Hematopoietic Cell Transplantation. We then compared transplantation outcomes between a fludarabine (Flu)- and melphalan (Mel)-based regimen (FM) and a Flu- and cyclophosphamide (Cy)-based regimen (FC). The median patient age at UCBT was 41 years. The median total nucleated cell and total CD34+ cell doses in a UCB unit at cryopreservation were 2.5 × 107/kg and 0.7 × 105/kg, respectively. The median follow-up period for survivors was 47 months. The cumulative incidence rate of neutrophil engraftment was 76.5%, and the 4-year overall survival (OS) rate was 64.3%. In multivariate analysis, the covariates that were significantly associated with a higher neutrophil engraftment were total CD34+ cell dose in an UCB unit (≥ 0.7 × 105/kg; hazard ratio, 0.57, P = 0.01) and total dose of TBI (4 Gy of TBI; hazard ratio, 0.32, P = 0.01). There was no significant difference in the cumulative incidence of neutrophil engraftment and the 4-year OS between the FM and FC groups. In conclusion, TBI-containing RIC regimens without ATG are suitable for adults with AA undergoing UCBT. There were no significant differences in transplantation outcomes between the FM and FC groups.

[Molecular pathogenesis and treatment of chronic lymphocytic leukemia].

Chronic lymphocytic leukemia (CLL) is a rare type of lymphoid malignancy among Japanese. Its clinical course is indolent, and the prognosis is good. The two types of CLL based on the mutation status of the IgH gene V segment have been documented in the literature. Then, the del (17p)/TP53 subtype is emphasized, and the treatment strategy for the three subtypes differs. Recent knowledge on molecular pathogenesis facilitated the usage of Bruton's tyrosine kinase (BTK) and BCL2 inhibitors for the treatment of CLL. A better response can be obtained with the use of these novel agents, resulting in a higher rate of negativity for measurable residual disease (MRD). The treatment strategy based on MRD negativity and the treatment outcomes of CLL will improve in future.