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Chordoma is a rare malignant bone tumor arising from notochordal tissue. Conventional treatments, such as radical resection and high-dose irradiation, frequently fail to control the tumor, resulting in recurrence and re-growth. In this study, genetic analysis of the tumor in a 72-year-old male patient with refractory conventional chordoma of the skull base revealed a high tumor mutational burden (TMB) and mutations in the MSH6 and MLH1 genes, which are found in Lynch syndrome. The patient and his family had a dense cancer history, and subsequent germline genetic testing revealed Lynch syndrome. This is the first report of a chordoma that has been genetically proven to be Lynch syndrome. Chordomas usually have low TMB; however, this is an unusual case, because the TMB was high, and immune checkpoint inhibitors effectively controlled the tumor. This case provides a basis for determining the indications for immunotherapy of chordoma based on the genetic analysis. Therefore, further extensive genetic analysis in the future will help to stratify the treatment of chordoma.

Chemotherapy in combination with mogamulizumab (Mog) was approved in Japan in 2014 for untreated aggressive adult T-cell leukaemia-lymphoma (ATL), but the survival benefit remains unclear. Therefore, we retrospectively analysed clinical outcomes in 39 transplant-ineligible patients with untreated aggressive ATL at Kumamoto University Hospital between 2010 and 2021. The probability of four-year overall survival was 46.3% in the first-line Mog-containing treatment group compared to 20.6% in the chemotherapy-alone group (p = 0.033). Furthermore, this survival benefit was observed even in the elderly. In conclusion, first-line Mog-containing treatment can be a promising strategy for transplant-ineligible patients with ATL, especially in the elderly.

Adult T-cell leukemia/lymphoma (ATL) is an aggressive neoplasm immunophenotypically resembling regulatory T cells, associated with human T-cell leukemia virus type-1. Here, we performed whole-genome sequencing (WGS) of 150 ATL cases to reveal the overarching landscape of genetic alterations in ATL. We discovered frequent (33%) loss-of-function alterations preferentially targeting the CIC long isoform, which were overlooked by previous exome-centric studies of various cancer types. Long but not short isoform–specific inactivation of Cic selectively increased CD4+CD25+Foxp3+ T cells in vivo. We also found recurrent (13%) 3′-truncations of REL, which induce transcriptional upregulation and generate gain-of-function proteins. More importantly, REL truncations are also common in diffuse large B-cell lymphoma, especially in germinal center B-cell–like subtype (12%). In the non-coding genome, we identified recurrent mutations in regulatory elements, particularly splice sites, of several driver genes. In addition, we characterized the different mutational processes operative in clustered hypermutation sites within and outside immunoglobulin/T-cell receptor genes and identified the mutational enrichment at the binding sites of host and viral transcription factors, suggesting their activities in ATL. By combining the analyses for coding and noncoding mutations, structural variations, and copy number alterations, we discovered 56 recurrently altered driver genes, including 11 novel ones. Finally, ATL cases were classified into 2 molecular groups with distinct clinical and genetic characteristics based on the driver alteration profile. Our findings not only help to improve diagnostic and therapeutic strategies in ATL, but also provide insights into T-cell biology and have implications for genome-wide cancer driver discovery.

There remains an unmet clinical need to identify which patients with diffuse large B-cell lymphoma (DLBCL) would benefit from central nervous system (CNS) prophylaxis, due to the low positive predictive value (PPV; 10%-15%) of the currently available predictive models. To stratify patients at high risk of developing CNS relapse, we retrospectively analyzed 182 patients with DLBCL initially treated with rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP), or a R-CHOP-like regimen. Among them, 17 patients relapsed with CNS involvement, and the 2-year rate of CNS relapse was 7.9%. Upon carrying out multivariate analysis, ≥3 extranodal sites and elevated soluble interleukin-2 receptor (sIL-2R) levels at diagnosis were identified as independent risk factors for CNS relapse. The 2-year and 3.5-year rates of CNS relapse were 57.1% and 78.6%, respectively, in patients with both elevated sIL-2R and ≥3 extranodal sites. Furthermore, combined use of these risk factors of both elevated sIL-2R and ≥3 extranodal sites resulted in a high PPV (71.4%), negative predictive value (93.1%), and overall accuracy (92.3%) for undergoing CNS relapse. In conclusion, we propose a simple and valuable tool to predict patients with DLBCL at very high risk of CNS relapse.

Supplementary Table S1 from Identification of Aberrantly Methylated Genes in Association with Adult T-Cell Leukemia

The prognosis of aggressive adult T-cell leukemia/lymphoma (ATL) is poor, and allogeneic hematopoietic stem-cell transplantation (allo-HSCT) is a curative treatment. To identify favorable prognostic patients after intensive chemotherapy, and who therefore might not require upfront allo-HSCT, we aimed to improve risk stratification of aggressive ATL patients aged

INTRODUCTION Adult T-cell leukemia-lymphoma (ATL) is a mature T-cell lymphoproliferative neoplasm caused by human T-cell leukemia virus type-1infection. There is no standard treatment for relapsed or refractory (r/r) ATL and clinical outcomes are poor. This systematic review examined the survival outcomes for r/r ATL treated with various systemic therapies. METHODS EMBASE and PubMed were searched for studies on r/r ATL, published between January 2010 and January 2020. The main outcome of interest was overall survival (OS). Median OS and an exploratory 30% OS time were assessed based on published data and Kaplan-Meier curves. RESULTS There were 21 unique treatment subgroups (from 14 studies), that met the eligibility criteria. Nine subgroups were mogamulizumab treatment, two were mogamulizumab prior to allogenic hematopoietic stem cell transplantation (allo-HSCT), five were allo-HSCT and five were other chemotherapy. Respectively, the median OS and 30% OS varied considerably in range for mogamulizumab treatment (2.2-17.6 months and 8.7-27.1 months), allo-HSCT (3.8-6.2 months and 7.5-19.8 months), and other chemotherapy arms (4.1-20.3 months and 7.1-17.0 months). CONCLUSION Mogamulizumab was the most frequently studied treatment regimen and can potentially provide longer survival compared to chemotherapy alone. Future comparisons with synthetic or historical control arms may enable clearer insights into treatment efficacy.

'Monitoring of immune responses following mogamulizumab-containing treatment in patients with adult T-cell leukaemia-lymphoma (ATL)' (MIMOGA) is a multicentre prospective clinical study (UMIN000008696). In the MIMOGA study, we found that a lower percentage of CD2- CD19+ B cells in peripheral blood mononuclear cells (PBMC) was a significant unfavourable prognostic factor for overall survival (OS). Accordingly, we then analysed the immunoglobulin G (IgG) heavy-chain repertoire in PBMC by high-throughput sequencing. Of the 101 patients enrolled in the MIMOGA study, for 81 a sufficient amount of PBMC RNA was available for repertoire sequencing analysis. Peripheral IgG B cells in patients with ATL had a restricted repertoire relative to those in healthy individuals. There was a significant positive correlation between the Shannon-Weaver diversity index (SWDI) for the IgG repertoire and proportions of B cells in the PBMC of the patients. Multivariate analysis identified two variables significantly affecting OS: a higher serum soluble interleukin-2 receptor level, and a lower SWDI for the IgG repertoire [hazard ratio, 2·124; 95% confidence interval, 1·114-4·049; n = 44]. The present study documents the importance of humoral immune responses in patients receiving mogamulizumab-containing treatment. Further investigation of strategies to enhance humoral immune responses in patients with ATL is warranted.

Follicular T-cell lymphoma (FTCL) is a rare disease, recently defined in the revised WHO classification Tumours of Haematopoietic and lymphoid tissues (4th edition). Although angioimmunoblastic T-cell lymphoma (AITL) and FTCL share similar T follicular helper (TFH) cell immunophenotypes and gene mutations, the clinical course of FTCL is not well characterized. Herein, we report the case of a 91-year-old woman with FTCL, who was successfully treated with corticosteroid. The patient, who had systemic lymphadenopathy and splenomegaly, was first diagnosed with necrotizing lymphadenitis. Re-biopsy was performed because of her persistent lymphadenopathy, which revealed FTCL. She was treated with corticosteroid because of her advanced age, poor performance, edema, and pleural effusion. After administering 100 mg prednisone, her condition improved and was discharged with prednisone tapering. Six-month positron emission tomography-computed tomography (PET-CT) scan showed complete metabolic remission. With a low dose of prednisone (6-10 mg), she remained disease-free for3 years. Thus, these findings suggest that corticosteroid treatment is effective in some patients with peripheral T-cell lymphoma of TFH origin, including FTCL.

Adult T-cell leukemia/lymphoma (ATL) is an aggressive non-Hodgkin lymphoma with poor prognosis and few treatment options for patients with relapsed, recurrent, or refractory disease. We evaluated the efficacy and safety of valemetostat, a potent enhancer of zeste homolog 2 (EZH2) and EZH1 inhibitor, in treating relapsed or refractory (R/R) ATL. This multicenter phase 2 trial enrolled patients with R/R aggressive ATL (acute, lymphoma, unfavorable chronic type). Patients received valemetostat 200 mg/day orally until progressive disease or unacceptable toxicity. The primary end point was overall response rate (ORR) centrally assessed by an independent efficacy assessment committee (IEAC). Secondary end points included best response in disease compartments, duration of response (DOR), pharmacokinetics, and safety. Twenty-five patients (median age, 69.0 years) with a median of 3 prior lines of therapy were enrolled; 24 had prior mogamulizumab treatment. The primary end point was met with a centrally reviewed ORR of 48.0% (90% confidence interval [CI], 30.5-65.9), including 5 complete and 7 partial remissions. Patients pretreated with mogamulizumab had an ORR of 45.8% (4 complete and 7 partial remissions). IEAC-assessed median DOR was not reached (NR) (95% CI, 1.87 to NR; months). Treatment-emergent adverse events (TEAEs) were manageable. TEAEs that occurred in ≥20% of patients included thrombocytopenia, anemia, alopecia, dysgeusia, neutropenia, lymphopenia, leukopenia, decreased appetite, and pyrexia. Grade ≥3 TEAEs included thrombocytopenia, anemia, lymphopenia, leukopenia, and neutropenia. Valemetostat demonstrated promising efficacy and tolerability in heavily pretreated patients, warranting further investigation in treating R/R ATL. This trial was registered at www.clinicaltrials.gov as #NCT04102150.

Adult T cell leukemia-lymphoma (ATL) is clinically heterogeneous and is classified into four subtypes: acute, lymphoma, chronic, and smoldering. Recently, a new prognostic index based on the value of soluble interleukin-2 receptor, denoted the "iATL-PI," has been proposed for patients with smoldering and chronic ATL. To evaluate the effectiveness of the iATL-PI, we re-analyzed our previously published data on 176 patients with smoldering or chronic ATL (76 smoldering, 100 chronic) diagnosed between 2010 and 2011, as well data from the subsequent follow-up study on prognosis between 2016 and 2017. The proportions for the low-, intermediate-, and high-risk iATL-PI groups at the time of ATL diagnosis were 44.7%, 48.7%, and 5% for smoldering ATL; 6.3%, 71.9%, and 21.9% for favorable chronic ATL; and 5.9%, 27.9%, and 66.2% for unfavorable chronic ATL, respectively. The survival of patients with smoldering or chronic ATL as a whole was significantly stratified according to the three iATL-PI groups. Most patients with unfavorable chronic ATL in the low iATL-PI risk group had indolent clinical courses. Our results showed that iATL may become a useful tool to predict the prognosis of smoldering and chronic ATL, which have diverse clinical courses.

We conducted a nationwide retrospective analysis of 116 hepatitis B virus (HBV) surface antigen (HBsAg)‐positive patients with diffuse large B‐cell lymphoma (DLBCL) and 278 HBsAg‐negative patients with DLBCL, as a control cohort, who received rituximab‐containing regimens as an induction chemotherapy at 30 Japanese medical centers between January 2004 and December 2014. Hepatitis was defined as an absolute serum alanine aminotransferase (ALT) level of ≥100 U/L. HBV reactivation‐related hepatitis was defined as hepatitis with an absolute serum HBV DNA level of ≥3.3 log IU/mL or an absolute increase of ≥2 log compared with the baseline value. HBsAg‐positive patients were divided into three groups based on anti–HBV prophylactic therapy: no nucleos(t)ide analogue (non–NA, n = 9), lamivudine (LAM, n = 20), and entecavir (ETV, n = 87). The 4‐year cumulative incidence (CI) of hepatitis in HBsAg‐positive and HBsAg‐negative patients was 21.1% and 14.6% (P = .081), respectively. The 4‐year CI of HBV reactivation‐related hepatitis was higher in HBsAg‐positive patients than in HBsAg‐negative patients (8.0% vs 0.4%; P, Prophylactic use of entecavir reduced HBV‐related hepatitis and mortality in HBsAg‐positive DLBCL treated with R‐chemotherapy. The 4‐year overall survival rate in HBsAg‐positive DLBCL patients receiving prophylactic entecavir was similar to that in HBsAg‐negative DLBCL.

Not available.

Human T-cell leukemia virus type 1 (HTLV-1) is a retrovirus that causes adult T-cell leukemia/lymphoma (ATL), a cancer of infected CD4+ T-cells. There is both sense and antisense transcription from the integrated provirus. Sense transcription tends to be suppressed, but antisense transcription is constitutively active. Various efforts have been made to elucidate the regulatory mechanism of HTLV-1 provirus for several decades; however, it remains unknown how HTLV-1 antisense transcription is maintained. Here, using proviral DNA-capture sequencing, we found a previously unidentified viral enhancer in the middle of the HTLV-1 provirus. The transcription factors, SRF and ELK-1, play a pivotal role in the activity of this enhancer. Aberrant transcription of genes in the proximity of integration sites was observed in freshly isolated ATL cells. This finding resolves certain long-standing questions concerning HTLV-1 persistence and pathogenesis. We anticipate that the DNA-capture-seq approach can be applied to analyze the regulatory mechanisms of other oncogenic viruses integrated into the host cellular genome.

Adult T‐cell leukemia/lymphoma (ATL) is a mature T‐cell neoplasm and is classified into four subtypes (acute, lymphoma, chronic, and smoldering) according to the Shimoyama classification, established in 1991 through several nationwide surveys based on the clinical diversity of patients diagnosed in 1983‐1987 in Japan. Thereafter, no such studies have been conducted. Recently, we conducted a nationwide hospital survey using the method of the 1980s studies, collected baseline data on 996 ATL patients diagnosed in 2010‐2011 from 126 hospitals, and reported their unique epidemiological characteristics. Here, we report the follow‐up results of registered ATL patients with the goal of evaluating current prognoses and treatment modalities as of 2016‐2017. Of 770 evaluable patients, 391 (50.8%) had acute‐type, 192 (24.9%) had lymphoma‐type, 106 (13.8%) had chronic‐type, and 81 (10.5%) had smoldering‐type ATL. The initial therapy regimens used for acute/lymphoma‐type ATL were vincristine, cyclophosphamide, doxorubicin and prednisone, followed by doxorubicin, ranimustine, and prednisone and then by vindesine, etoposide, carboplatin, and prednisone (VCAP‐AMP‐VECP)‐like in 38.5/41.7% and cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP)‐like in 14.6/13.7% of patients. Allogeneic hematopoietic stem cell transplantation was used to treat 15.9/10.4% of acute/lymphoma‐type ATL patients. The 4‐year survival rates (the median survival time, days) for acute‐, lymphoma‐, unfavorable chronic‐, favorable chronic‐, and smoldering‐type ATL were 16.8% (252), 19.6% (305), 26.6% (572), 62.1% (1937), and 59.8% (1851), respectively. The 4‐year survival rates for acute‐ and lymphoma‐type ATL improved compared with those reported in 1991, but those for chronic‐ and smoldering‐type ATL were not. Further efforts are warranted to develop more efficient therapeutic strategies to improve the prognosis of ATL in Japan., The survival curve shows that the prognoses of patients with acute and lymphoma‐type ATL in Japan have improved modestly, but those of patients with chronic and smoldering‐type ATL have not improved.

The efficiency of upfront consolidation with high‐dose chemotherapy/autologous stem‐cell transplantation (HDCT/ASCT) for newly diagnosed high‐risk diffuse large B‐cell lymphoma (DLBCL) may be influenced by induction chemotherapy. To select better induction chemotherapy regimens for HDCT/ASCT, a randomized phase II study was conducted in high‐risk DLBCL patients having an age‐adjusted International Prognostic Index (aaIPI) score of 2 or 3. As induction chemotherapy, 6 cycles of R‐CHOP‐14 (arm A) or 3 cycles of R‐CHOP‐14 followed by 3 cycles of CHASER (arm B) were planned, and patients who responded proceeded to HDCT with LEED and ASCT. The primary endpoint was 2‐y progression‐free survival (PFS), and the main secondary endpoints included overall survival, overall response rate, and adverse events (AEs). In total, 71 patients were enrolled. With a median follow‐up of 40.3 mo, 2‐y PFS in arms A and B were 68.6% (95% confidence interval [CI], 50.5%‐81.2%) and 66.7% (95% CI: 48.8%‐79.5%), respectively. Overall survival at 2 y in arms A and B was 74.3% (95% CI: 56.4%‐85.7%) and 83.3% (95% CI: 66.6%‐92.1%). Overall response rates were 82.9% in arm A and 69.4% in arm B. During induction chemotherapy, 45.7% and 75.0% of patients in arms A and B, respectively, had grade ≥ 3 non‐hematologic toxicities. One patient in arm A and 6 in arm B discontinued induction chemotherapy due to AEs. In conclusion, R‐CHOP‐14 showed higher 2‐y PFS and less toxicity compared with R‐CHOP‐14/CHASER in patients with high‐risk DLBCL, suggesting the former to be a more promising induction regimen for further investigations (UMIN‐CTR, UMIN000003823)., The efficiency of upfront consolidation with high‐dose chemotherapy/autologous stem‐cell transplantation (HDCT/ASCT) for newly diagnosed high‐risk diffuse large B‐cell lymphoma (DLBCL) may be influenced by induction chemotherapy. To select better induction chemotherapy regimens for HDCT/ASCT, a randomized phase II study was conducted in patients with high‐risk DLBCL who had an age‐adjusted International Prognostic Index (aaIPI) score of 2 or 3. R‐CHOP‐14 showed higher 2‐y PFS and less toxicity compared with R‐CHOP‐14/CHASER in patients with high‐risk DLBCL, suggesting the former to be a more promising induction regimen for further investigations.

Cefepime is known to exert bactericidal activity against Pseudomonas aeruginosa. Cefepime-induced neurotoxicity, most likely caused by increased exposure, has recently become a major concern in clinical practice; therefore, appropriate dose reduction of cefepime should be applied with respect to patients with low cefepime clearance (mostly eliminated by the kidneys). Here, we report a case in which Bayesian prediction-based therapeutic drug monitoring (Bayes-TDM) was effectively used to reduce the dose of cefepime in a patient with pneumonia to prevent neurotoxic complications. A woman (age: 59 years, body weight: 32.5 kg, serum creatinine concentration: 1.02 mg/dL) developed pneumonia caused by P. aeruginosa while receiving treatment for scleroderma and systemic lupus erythematosus. She started treatment with a dosing regimen of 1.0 g of cefepime every 8 h (day X). On day X+5, aphasia developed, and the serum cefepime concentration was 71.3 mg/L at trough. This concentration was twice or thrice higher than the reported safe concentration of cefepime (22 or 35 mg/L at trough). Therefore, we reduced the dose of cefepime to 0.5 g every 12 h using Bayes-TDM from day X+7. As a result, the severity of aphasia decreased by day X+10, and this dose was successfully continued up to day X+13 without further adjustment. In conclusion, individualizing doses by Bayes-TDM may be useful in preventing adverse effects associated with cefepime treatment.

Although the superiority of vancomycin dosing based on area under the concentration-time curve (AUC0-24) over that based on trough concentration has been reported, a dosing strategy to achieve the target AUC0-24 has yet to be developed. The objective of this study was to develop a convenient useable nomogram for vancomycin dosing to obtain the target AUC0-24 (400 μg h/mL). The nomogram was pharmacokinetically developed in a retrospective manner. The number of enrolled patients and concentrations was 166 and 309 for development of the nomogram, 99 and 181 for evaluation of the nomogram, respectively. The nomogram was developed as doses per personal body weight corresponding to each range of estimated glomerular filtration rate (eGFR), which was identified to be the covariate for vancomycin clearance by non-linear mixed effect modeling. The nomogram described the surrogate trough concentration for the target AUC0-24 was calculatedly different for each eGFR range (9.3–15.0 μg/mL). The rate of attainment of therapeutic range using surrogate trough concentration to obtain the target AUC0-24 was 63.8% in the evaluation period. We have developed and evaluated the first convenient useable nomogram of vancomycin dosing to obtain the target AUC0-24.

A 62-year-old man visited the Department of Otorhinolaryngology at our hospital with a chief complaint of a pharyngeal mass. He was admitted to our department with a diagnosis of T-cell lymphoma based on a biopsy of a mesopharyngeal tumor. Although clonality analysis was not performed due to the lack of an appropriate sample, we considered the possibility of lymphoma-type (Lugano classification stage II) adult T-cell leukemia-lymphoma (ATL), as the anti-HTLV-1 antibody was positive. During the course of the disease, the peripheral blood smear revealed atypical lymphocytes with cleaved nuclei, and inverse PCR was performed with DNA extracted from those cells; however, the result showed that the pattern of HTLV-1 proviral DNA integration sites was polyclonal. Further, we performed RNA in situ hybridization targeting HTLV-1 bZIP factor (HBZ-ISH) using the formalin-fixed paraffin-embedded (FFPE) tissue samples of the mesopharyngeal tumor, and a high expression of HBZ was found in the tumor cells, leading to the diagnosis of ATL. These findings suggest the effectiveness of the novel diagnostic method using FFPE tissue samples for ATL.

In order to identify genomic biomarkers for the outcome of mogamulizumab-containing treatment, an integrated molecular analysis of adult T-cell leukemia/lymphoma (ATL) was conducted on 64 mogamulizumab-naïve patients. Among driver genes, CCR4 and CCR7 alterations were observed in 22% and 11% of the patients, respectively, both consisting of single nucleotide variants (SNV)/insertion-deletions (indels) in the C-terminus. Patients with CCR4 alterations or without CCR7 alterations exhibited a more favorable clinical response (complete response [CR] rate 93%, 13/14; P=0.024, and CR rate 71%, 40/56; P=0.036, respectively). Additionally, TP53, CD28, and CD274 alterations were identified in 35%, 16%, and 10% of the patients, respectively. TP53 alterations included SNV/indels or copy number variations (CNV) such as homozygous deletion; CD28 alterations included SNV, CNV such as amplification, or fusion; CD274 alterations included CNV such as amplification, or structural variants. Univariate analysis revealed that TP53, CD28 or CD274 alterations were associated with worse overall survival (OS) (hazard ratio [HR]: 2.330, 95% confidence interval [CI]: 1.183-4.589; HR: 3.191, 95% CI: 1.287- 7.911; HR: 3.301, 95% CI: 1.130-9.641, respectively) but that CCR4 alterations were associated with better OS (HR: 0.286, 95% CI: 0.087-0.933). Multivariate analysis indicated that in addition to performance status, TP53, CCR4 or CD274 alterations (HR: 2.467, 95% CI: 1.197-5.085; HR: 0.155, 95% CI: 0.031-0.778; HR: 14.393, 95% CI: 2.437-85.005, respectively) were independently and significantly associated with OS. The present study contributes to the establishment of precision medicine using mogamulizumab in ATL patients.

Adult T‐cell leukemia‐lymphoma (ATL) is a T‐cell malignancy that is endemic to Japan. In this latest nationwide study of ATL, we collected the data from 4 nationwide registries of patients diagnosed in 2012‐2013; the Hematology Blood Disease, the Skin Cancer Society, the Hospital‐Based Cancer Registries, and information from the hospitals that participated in the Japanese nationwide survey of ATL in 2010‐2011. In the present study, 2614 patients with ATL were diagnosed based on the registries, and 117 departments registered 1042 patients. Among these patients, 984 were eligible for analysis. The median age at diagnosis was 69 y. A larger proportion of patients with ATL older than 70 y was diagnosed with the lymphoma subtype, and more than half of the patients with ATL in the metropolitan areas were born in the human T‐cell leukemia virus type I (HTLV‐1)‐endemic areas of Kyushu/Okinawa, which are almost identical to the findings in our 2010‐2011 study. Additionally, we identified that patients with ATL migrated from the endemic areas for HTLV‐1 to the non‐endemic metropolitan areas. The present study was able to reduce the burden of searching each hospital and to update the clinico‐epidemiological characteristics of a large number of patients with ATL in Japan, suggesting the usefulness and feasibility of the novel data collection method. The establishment of a more sophisticated database management system for ATL is necessary for future continuous surveys., We identified that ATL patients shifted from areas endemic for HTLV‐1 to non‐endemic metropolitan areas. The median age at diagnosis was 69 y, which was significantly older than that in the 1980s and 1990s. We conducted a nationwide survey of ATL during 2012‐2013 by modifying data acquisition from 4 nationwide registries.

Tazemetostat is a selective, reversible, small‐molecule inhibitor of the histone methyltransferase enzyme, enhancer of zest homolog 2 (EZH2). In this multicenter, open‐label, phase II study, we assessed the efficacy and safety of tazemetostat in Japanese patients with relapsed or refractory (R/R) B‐cell non‐Hodgkin lymphoma harboring the EZH2 mutation. Tazemetostat (800 mg twice daily) was given orally (28‐day cycle) until disease progression or unacceptable toxicity. Among the 20 eligible patients, 17 were enrolled in cohort 1 (follicular lymphoma [FL]), and three were enrolled in cohort 2 (diffuse large B‐cell lymphoma). At data cut‐off, the objective response rate in cohort 1 was 76.5%, including six patients (35.3%) with complete response and seven patients (41.2%) with partial response (PR). All three patients in cohort 2 achieved PR. In cohort 1, median progression‐free survival (PFS) was not reached at the median follow‐up of 12.9 months. The estimated PFS rate at 12 and 15 months was 94.1% and 73.2%, respectively. The most common grade 3 treatment‐emergent adverse event (TEAE) was lymphopenia (n = 2). Grade 4 TEAEs included hypertriglyceridemia and pneumonia aspiration (n = 1 each), which were not related to tazemetostat. Treatment‐emergent adverse events leading to study drug discontinuation were reported in four of the 20 patients, indicating that the safety profile of tazemetostat was acceptable and manageable. Tazemetostat 800 mg twice daily showed encouraging efficacy in patients with R/R EZH2 mutation‐positive FL with a manageable safety profile in the overall population. Thus, tazemetostat could be a potential treatment for R/R EZH2 mutation‐positive FL., Percentage change from baseline in sum of the product of the perpendicular diameters of target lesions based on independent reviewer assessment.

Mogamulizumab (Mog) is effective against adult T-cell leukemia-lymphoma (ATL), but as we reported previously, Mog increases the incidence of severe acute GVHD when administered before allogeneic hematopoietic cell transplantation (allo-HCT). Here, we report the cases of two ATL patients who did not develop acute GVHD despite receiving Mog before allo-HCT. Case 1: a 63-year-old female who underwent allo-HCT from an HLA-matched donor 2 months after the last dose of Mog. Case 2: a 47-year-old male with ATL that relapsed 3 months after first allo-HCT. He received eight doses of Mog and underwent a second allo-HCT from a haploidentical donor 4 months after the last dose of Mog. Mog blood levels were measured and lymphocytes analyzed by mass cytometry. Mog blood levels measured before starting the conditioning regimens were low. A small proportion of regulatory T cells (Tregs) was detected before and shortly after allo-HCT. When using Mog before allo-HCT, it is important to consider the number of Mog doses and the interval from the last dose of Mog to allo-HCT. Analyzing Mog blood levels and Treg counts before and after allo-HCT should also be useful.

Adult T‐cell leukemia‐lymphoma (ATL) is caused by human T‐cell leukemia virus type 1 (HTLV‐1) infection. Among HTLV‐1 encoded genes, HTLV‐1 bZIP factor (HBZ) and tax are critical for the leukemogenesis of ATL. Adult T‐cell leukemia‐lymphoma needs a long latent period before onset, indicating that both viral genes and alterations (genetic and epigenetic) of the host genome play important roles for leukemogenesis. Viral genes influence genetic and epigenetic changes of the host genome, indicating that the virus is of primary importance in leukemogenesis. HBZ is expressed in all ATL cases, whereas Tax expression is heterogeneous among ATL cases. Different patterns of viral gene expression in tumors are also observed for Epstein‐Barr virus. We propose three subtypes of ATL cases based on Tax expression: high, intermittent, and lost expression. HBZ is detected in all ATL cases. Approximately 25% of all ATL cases lost Tax expression at infection of HTLV‐1, indicating that HBZ is the only viral gene responsible for leukemogenesis in addition to genetic and epigenetic changes of the host genes in these ATL cases. The host immune responses to Tax are also implicated in the heterogeneity of ATL. Thus, ATL is a heterogeneous disease in terms of its viral gene expression, which is important for pathogenesis of this intractable lymphomatous neoplasm., In this review, we describe the heterogeneity of adult T‐cell leukemia‐lymphoma (ATL) in regard to viral gene expression, and propose three subtypes of ATL. These findings lead to an understanding of pathogenesis by human T‐cell leukemia virus type 1 and new therapeutic strategies for ATL.

Human T-cell leukemia virus type 1 (HTLV-1) is a retrovirus that causes a cancer of infected cells called adult T-cell leukemia (ATL). There is both sense and antisense transcription from the integrated provirus. Sense transcription tends to be suppressed, but antisense transcription is constitutively active in vivo even in proviruses lacking the 5’ long terminal repeat (LTR), a known viral enhancer and promoter. Various efforts have been made to elucidate the regulatory mechanism of HTLV-1 provirus for several decades; however, it remains unknown how HTLV-1 antisense transcription is maintained. Here, using proviral DNA-capture followed by high-throughput sequencing, we found a previously unidentified viral enhancer not in the LTR but in the middle of the HTLV-1 provirus. The host transcription factors, SRF and ELK-1, bind to this enhancer region both in cell lines and in freshly isolated ATL cells. HTLV-1 containing mutations in the SRF- and ELK-1-binding sites markedly decreased chromatin openness at the viral enhancer, viral gene transcription, and enhancing effects on host gene transcription near the viral integration site. Aberrant host genome transcription was observed at nearby integration sites in defective proviruses containing the enhancer in ATL cells. This finding reveals how the exogenous retrovirus achieves persistent infection in the host via the internal viral enhancer and resolves certain long-standing questions concerning HTLV-1 infection. We anticipate that the DNA-capture-seq approach can be applied to analyze regulatory mechanisms of other oncogenic viruses integrated into the host cellular genome.

Vancomycin is often employed as an antibacterial agent against Gram-positive bacteria, although dose-dependent nephrotoxicity is a concern. Although the risk may be reduced by therapeutic drug monitoring (TDM) guided by area under the concentration–time curve (an attempt to target an AUC > 400 μg•h/mL by Bayesian prediction: AUC400-guided TDM), the clinical efficacy of AUC400-guided TDM compared with trough concentration-guided TDM within 15–20 μg/mL (Trough15–20-guided TDM) has yet to be determined. We aimed to retrospectively evaluate the difference in the incidence rate of acute kidney injury (AKI), classified according to the Acute Kidney Injury Network, between these TDM groups. Individual AUC in the AUC400-guided TDM group was calculated by Bayesian prediction using trough and peak concentrations (within 3 h after the end of infusion). The AKI incidence in the Trough15–20-guided TDM group was 28.8% (15/52 patients) compared with an AKI incidence in the AUC400-guided TDM group of 9.1% (2/22 patients). Application of AUC400-guided TDM was identified as an independent factor for avoiding the incidence of AKI by Cox hazard regression analysis [hazard ratio = 0.168, 95% confidence interval (CI) 0.034–0.839] and logistic regression analysis (odds ratio = 0.037, 95% CI 0.003–0.285). As the estimated glomerular filtration rate (eGFR) improved, the surrogate target trough concentration for an AUC > 400 μg•h/mL was lowered (intercept 15.0074, slope –0.0598). In conclusion, AUC400-guided TDM may be superior to Trough15–20-guided TDM for the reduction of nephrotoxicity during vancomycin therapy.

Bacteremia is often caused by gram-negative bacteria (represented by EKP; Escherichia coli, Klebsiella species, and Proteus mirabilis), and the excessive use of cefazolin, as the first-line antimicrobial in its treatment, has been a source of concern in the emergence of resistant strains. As an antimicrobial, cefotiam may be an alternative to cefazolin; however, little evidence is available for its use in the treatment of bacteremia. The purpose of this non-inferiority study was to retrospectively compare the therapeutic efficacy of cefotiam with some antimicrobials of narrow spectrum (cefazolin, cefmetazole, and flomoxef) in the treatment of EKP-induced bacteremia. The number of patients recruited was 32 in the cefotiam group and 29 in the control group. In the primary endpoint, the survival rate on day 28 for the cefotiam group and the control group was 93.5% and 89.3%, respectively (relative risk at day 28, 1.048; 95% confidence interval, 0.894-1.227). In the secondary end point, treatment success rate in the two groups was 71.9% and 69.0%, respectively (relative risk, 1.042; 95% confidence interval, 0.752-1.445). Intensive care unit admission, low body weight, hypoalbuminemia, and infections unassociated with the urinary tract were identified to be the risk factors responsible for treatment failure. We demonstrated cefotiam may be non-inferior to other antimicrobials of similar spectrum, in terms of survival rate, in EKP-induced bacteremia.

Additional file 2: Table S1. For performance (serological sensitivity) comparison between WB and LIA, 110 CLEIA-reactive, WB-indeterminate, and provirus-positive blood samples were collected and tested by LIA. CLEIA-specific antibody titers, the profiles of both WB and LIA blot patterns, the judgments by each test method, and the PVLs by PCR in all the blood samples used in this experiment are listed. NT: not tested, R: reactive, and I: indeterminate.

Additional file 4. Diagnostic Guidelines for Human T-Cell Leukemia Virus Type 1 Infection in Japan, Version 2 (November 2019).

Summary Background Standard treatment for untreated advanced-stage follicular lymphoma is rituximab plus chemotherapy. The incidence of histological transformation of follicular lymphoma has been reported only in heterogeneously treated populations and rarely with long-term follow-up. Additionally, the incidence of secondary malignancies after treatment, without high-dose therapy for follicular lymphoma, is largely unknown. The aim of our study was to assess progression-free survival, overall survival, incidence of secondary malignancies, and incidence of histological transformation in a 10-year follow-up analysis of the JCOG0203 trial. Methods In the phase 2–3 randomised JCOG0203 trial, previously untreated patients with stage III or IV indolent B-cell lymphoma, including grades 1–3 follicular lymphoma, from 44 hospital centres in Japan, were randomly assigned (1:1) by use of a minimisation method to receive six cycles of R-CHOP (rituximab [375 mg/m2], given on day 1, plus cyclophosphamide [750 mg/m2], doxorubicin [50 mg/m2], vincristine [1·4 mg/m2, capped at 2·0 mg] given intravenously on day 3, and oral prednisone [100 mg once daily on days 3–7]) every 3 weeks (R-CHOP-21) or every 2 weeks (enabled by mandatory granulocyte-colony stimulating factor administration once daily for 6 days, starting on day 8; R-CHOP-14) without rituximab maintenance. Age, bulky disease (nodal or extranodal mass ≥10 cm in diameter on CT), and institution were used as adjustment factors. Investigators enrolled participants, and assignment to trial groups was done with a computer-assisted randomisation allocation sequence that took place centrally at the Japan Clinical Oncology Group Data Center, without the intervention of investigators. Interventions were not masked for patients or investigators. Data were collected 10 years after enrolment of the last patient. The primary endpoint of the phase 3 part of the study was progression-free survival, and the primary endpoint of the phase 2 part of the study was the proportion of patients who achieved a complete response. Accrual was 4·5 years, and follow-up was 3 years after registration was closed. Data were updated on the cutoff date of Feb 28, 2017. Intention-to-treat analyses (ie, progression-free survival, overall survival, and incidence of secondary malignancies) were predefined, to be done at 10 years after the last patient was enrolled. An additional analysis of the incidence of histological transformation was defined 15 years after the protocol, on May 8, 2017, in a supplementary analysis plan, and assessed at 10 years after the last patient was enrolled. Follow-up is ongoing. This trial is registered with ClinicalTrials.gov, number NCT00147121. Findings Between Sept 1, 2002, and Feb 28, 2007, 300 patients were enrolled, and 149 (50%) were assigned to the R-CHOP-21 group and 151 (50%) were assigned to the R-CHOP-14 group. After eligibility was assessed, one patient was excluded from the R-CHOP-21 group. 10-year progression-free survival was not different between groups (R-CHOP-21 33%, 95% CI 25–41; R-CHOP-14 39%, 31–47; hazard ratio 0·89, 95% CI 0·67–1·17). In 248 patients with grade 1–3a follicular lymphoma, progression-free survival was 39% (33–45) at 8 years and 36% (30–42) at 10 years. The cumulative incidence of histological transformation was 3·2% (95% CI 1·5–6·0) at 5 years, 8·5% (5·4–12·4) at 8 years, and 9·3% (6·1–13·4) at 10 years after enrolment. At 10 years, the cumulative incidence of secondary malignancies was 8·1% (5·1–12·0) and the cumulative incidence of haematological secondary malignancies was 2·9% (1·3–5·5). Interpretation R-CHOP is a viable option for first-line treatment in patients with newly diagnosed advanced follicular lymphoma. Clinicians choosing a first-line treatment for patients with follicular lymphoma should be cautious of secondary malignancies caused by immunochemotherapy and severe complications of infectious diseases in the long-term follow-up—both of which could lead to death. Funding National Cancer Center and Ministry of Health, Labour and Welfare of Japan.

Quantitative PCR (qPCR) of human T-cell leukemia virus type 1 (HTLV-1) provirus is used for HTLV-1 testing and for assessment of risk of HTLV-1-related diseases. In this study, a reference material was developed for standardizing HTLV-1 qPCR. Freeze-dried TL-Om1 cells diluted with Jurkat cells were prepared and an assigned value for proviral load (PVL) of 2.71 copies/100 cells was determined by digital PCR. Nine Japanese laboratories using their own methods evaluated the PVLs of this reference material as 1.08-3.49 copies/100 cells. The maximum difference between laboratories was 3.2-fold. Correcting measured PVLs by using a formula incorporating the assigned value of this reference material should minimize such discrepancies.

Adult T-cell leukemia/lymphoma (ATL) is a heterogeneous group of peripheral T-cell malignancies characterized by human T-cell leukemia virus type-1 infection, whose genetic profile has recently been fully investigated. However, it is still poorly understood how these alterations affect clinical features and prognosis. We investigated the effects of genetic alterations commonly found in ATL on disease phenotypes and clinical outcomes, based on genotyping data obtained from 414 and 463 ATL patients using targeted-capture sequencing and single nucleotide polymorphism array karyotyping, respectively. Aggressive (acute/lymphoma) subtypes were associated with an increased burden of genetic and epigenetic alterations, higher frequencies of TP53 and IRF4 mutations, and many copy number alterations (CNAs), including PD-L1 amplifications and CDKN2A deletions, compared with indolent (chronic/smoldering) subtypes. By contrast, STAT3 mutations were more characteristic of indolent ATL. Higher numbers of somatic mutations and CNAs significantly correlated with worse survival. In a multivariate analysis incorporating both clinical factors and genetic alterations, the Japan Clinical Oncology Group prognostic index high-risk, older age, PRKCB mutations, and PD-L1 amplifications were independent poor prognostic factors in aggressive ATL. In indolent ATL, IRF4 mutations, PD-L1 amplifications, and CDKN2A deletions were significantly associated with shorter survival, although the chronic subtype with unfavorable clinical factors was only marginally significant. Thus, somatic alterations characterizing aggressive diseases predict worse prognosis in indolent ATL, among which PD-L1 amplifications are a strong genetic predictor in both aggressive and indolent ATL. ATL subtypes are further classified into molecularly distinct subsets with different prognosis. Genetic profiling might contribute to improved prognostication and management of ATL patients.

Background: Enhancer of zeste homolog 2 (EZH2) and its close homolog, EZH1, catalyze the attachment of 3 methyl groups to histone H3 at lysine 27 (H3K27me3). H3K27me3 is an epigenetic mark involved in downregulating gene expression associated with tumor suppression and cell differentiation. Recent evidence suggests that adult T-cell leukemia/lymphoma (ATL) can be driven by epigenetic dysregulation (Blood. 2016;127:1790-1802). Specifically, altered EZH2 expression has been implicated in the development and progression of ATL. Valemetostat tosylate (DS-3201b; valemetostat) is a novel, potent, and selective dual inhibitor of EZH2 and EZH1 that has demonstrated antitumor activity against hematologic malignancies, especially T-cell lymphoma, including relapsed or refractory (R/R) ATL in a phase 1 study (EHA 2021. Abstract S218). Here, we report the results from the primary analysis of a pivotal phase 2 study of valemetostat in Japanese patients (pts) with R/R ATL. Aims: This multicenter, single-arm, open-label, phase 2 study (NCT04102150) evaluated the efficacy and safety of single-agent valemetostat in pts with R/R ATL. The primary objective was to evaluate efficacy by central efficacy assessment committee (EAC)-assessed overall response rate (ORR), defined as the proportion of pts whose best response was complete remission (CR), uncertified CR, or partial remission using international consensus criteria (J Clin Oncol. 2009;27:453-59). The null hypothesis was an ORR of ≤5% (binomial test with a 1-sided significance level of 5%). Secondary outcome measures included CR rate, duration of response (DOR) per EAC, efficacy per investigator (INV) assessment, and the safety and pharmacokinetics of valemetostat. Methods: Pts ≥20 years of age with R/R ATL (acute, lymphomatous, or unfavorable chronic type) were enrolled from 24 sites in Japan. Pts must have had a positive antihuman T-cell leukemia virus type 1 antibody serum test and received prior therapy with mogamulizumab or ≥1 prior systemic therapy in the case of intolerance of, or contraindication for, mogamulizumab. Pts with prior allogeneic hematopoietic stem cell transplant were excluded. Valemetostat 200 mg was orally administered once daily in continuous 28-day cycles until disease progression or intolerance. The EAC-determined efficacy assessment was based on central evaluation of radiographic images and clinical data, including peripheral blood, skin, and bone marrow lesions (J Clin Oncol. 2009;27:453-59). Results: At the time of data cutoff (April 24, 2021), the study enrolled the planned 25 pts which included 16, 6, and 3 pts with acute, lymphomatous, or unfavorable chronic ATL subtypes, respectively. The median age was 69 years (range, 59-84 years). The median number of prior lines of therapy was 3 (range, 1-8). 24 pts (96.0%) had prior treatment with mogamulizumab. The study met its primary endpoint: with a median follow-up of 28 weeks (range, 14-71 weeks), valemetostat resulted in a 48% (12/25) ORR per EAC assessment (P 8 of 25 pts (32%) remained on treatment. 25 pts (100%) experienced ≥1 treatment-emergent adverse event (TEAE). Grade ≥3 TEAEs occurred in 15 pts (60%), and grade ≥3 serious TEAEs occurred in 6 pts (24%); valemetostat was not associated with any deaths. Dose interruption or reduction due to TEAEs occurred in 5 (20%) and 2 (8%) pts, respectively. Two pts (8%) discontinued due to TEAEs. The most common TEAEs (≥30% of pts) were platelet count decreased (80%), dysgeusia (36%), anemia (48%), and alopecia (40%); grade ≥4 platelet count decreased occurred in 3 pts (12%). Summary/Conclusions: Valemetostat resulted in a high response rate and durable antitumor effect in Japanese pts with R/R ATL, the majority of whom were pretreated with mogamulizumab. Valemetostat's safety profile was manageable. These results are consistent with those observed in the phase 1 study conducted in Japan and the US, suggesting that valemetostat could be a new treatment option for pts with R/R ATL. Valemetostat is also being evaluated in a global phase 2 study in pts with R/R ATL and R/R peripheral T-cell lymphoma (NCT04703192). Figure 1 Figure 1. Disclosures Yoshimitsu: Sanofi: Honoraria; Takeda: Honoraria; Novartis: Honoraria. Izutsu: Kyowa Kirin: Honoraria, Research Funding; Incyte: Research Funding; Chugai: Honoraria, Research Funding; Bayer: Research Funding; Beigene: Research Funding; AstraZeneca: Honoraria, Research Funding; Yakult: Research Funding; AbbVie: Honoraria, Research Funding; Takeda Pharmaceutical: Honoraria, Research Funding; HUYA Bioscience International: Research Funding; Eisai: Honoraria, Research Funding; MSD: Research Funding; Janssen: Honoraria, Research Funding; Genmab: Honoraria, Research Funding; Celgene: Honoraria, Research Funding; Daiichi Sankyo: Honoraria, Research Funding; Novartis: Honoraria, Research Funding; Ono: Honoraria, Research Funding; Pfizer: Research Funding; Symbio: Honoraria, Research Funding; Allergan Japan: Honoraria; FUJI FILM Toyama Chemical: Honoraria. Makita: Takeda: Consultancy, Honoraria; SymBio: Honoraria; Novartis: Honoraria; Eisai: Honoraria; Daiichi-Sankyo: Consultancy; CSL Behring: Honoraria; Chugai: Honoraria; BMS: Consultancy, Honoraria. Nosaka: Eisai Co., Ltd: Honoraria; Celgene K.K.: Honoraria; Kyowa Kirin Co., Ltd: Consultancy, Honoraria, Research Funding; Meiji Seika Parma Co., Ltd: Honoraria; Chugai Pharmaceutical Co., Ltd.: Research Funding; Janssen Pharmaceutical K.K.: Honoraria; Bristol Myers Squibb: Honoraria. Utsunomiya: Novartis Pharma: Honoraria; Kyowa Kirin: Honoraria; Daiichi Sankyo: Honoraria; Celgene: Honoraria; Pfizer: Honoraria; Janssen Pharmaceutical: Honoraria; JIMRO: Honoraria; Meiji Seika Pharma: Honoraria; Otsuka Medical Devices: Honoraria. Kusumoto: Daiichi Sankyo: Research Funding; Chugai: Honoraria, Research Funding; Kyowa Kirin: Honoraria. Tsukasaki: Solasia Pharma: Consultancy; Meiji Seika Pharma: Consultancy; Yakuruto: Consultancy; HUYABIO: Consultancy, Research Funding; Ono Pharma: Consultancy; Daiichi Sankyo: Consultancy, Research Funding; Takeda: Honoraria; Kyowa-hakko/Kirin: Honoraria, Research Funding; Eizai: Honoraria, Research Funding; Byer: Research Funding; Chugai Pharma: Honoraria, Research Funding; Celgene: Honoraria, Research Funding. Ono: Chugai Pharmaceutical Co., Ltd.: Honoraria, Research Funding; Eisai Co., Ltd.: Honoraria; Janssen Pharmaceutical K.K: Honoraria; DAIICHI SANKYO COMPANY, LIMITED.: Honoraria; Mundipharma K.K.: Honoraria; TAIHO PHARMACEUTICAL CO., LTD.: Research Funding; Merck Sharp & Dohme: Honoraria, Research Funding; Astellas Pharma Inc.: Honoraria; Bristol-Myers Squibb Company: Honoraria; Novartis Pharma KK: Honoraria; Pfizer Japan Inc.: Honoraria; Otsuka Pharmaceutical Co., Ltd.: Honoraria; ONO PHARMACEUTICAL CO., LTD.: Honoraria, Research Funding; Takeda Pharmaceutical Company Limited.: Honoraria; Kyowa Kirin Co., Ltd.: Honoraria, Research Funding; Celgene: Honoraria, Research Funding. Rai: Chugai Pharmaceutical: Speakers Bureau; Ono Pharmaceutical: Speakers Bureau; Janssen Pharmaceutical: Speakers Bureau. Yamada: Daiichi Sankyo: Current Employment. Kato: Bristol Myers Squibb: Current equity holder in publicly-traded company; Daiichi Sankyo: Current Employment. Tachibana: Daiichi Sankyo: Current Employment. Kakurai: Daiichi Sankyo: Current Employment. Adachi: Daiichi Sankyo: Current Employment. Tobinai: Celgene: Consultancy, Honoraria; Chugai Pharmaceutical: Honoraria; Eisai: Honoraria; Daiichi Sankyo: Consultancy, Honoraria; HUYA Bioscience International: Consultancy, Honoraria; Kyowa Kirin: Honoraria; Mundipharma: Consultancy, Honoraria; Ono Pharmaceutical: Consultancy, Honoraria; Solasia Pharma: Honoraria; Takeda Pharmaceutical: Consultancy, Honoraria; Yakult: Honoraria; Zenyaku Kogyo: Consultancy, Honoraria. Yonekura: AbbVie: Honoraria; Amgen: Honoraria; Celgene: Honoraria; Daiichi Sankyo: Honoraria; Eisai: Honoraria; Eli Lilly Japan: Honoraria; Janssen Pharmaceuticals: Honoraria; Kaken Pharmaceutical: Honoraria; Kyowa Kirin: Honoraria; Maruho: Honoraria; Minophagen Pharmaceutical: Honoraria; Novartis: Honoraria; Sanofi: Honoraria; Taiho Pharmaceutical: Honoraria; Torii Pharmaceutical: Honoraria; UCB Japan: Honoraria. Ishitsuka: Pfizer: Other: Personal fees; Astellas Pharma: Other: Personal fees, Research Funding; Genzyme: Other: Personal fees; Sumitomo Dainippon Pharma: Other: Personal fees, Research Funding; Eisai: Other: Personal fees, Research Funding; Novartis: Other: Personal fees; Janssen Pharmaceuticals: Other: Personal fees; Taiho Pharmaceuticals: Other: Personal fees, Research Funding; Mundipharma: Other: Personal fees; Takeda: Other: Personal fees, Research Funding; BMS: Other; Chugai Pharmaceutical: Honoraria, Other: Personal fees, Research Funding; Celgene: Honoraria, Other: Personal fees; Ono Pharmaceutical: Other: Personal fees, Research Funding; Kyowa Kirin: Other: Personal fees, Research Funding; Daiichi Sankyo: Consultancy, Other: Personal fees; Mochida: Other: Personal fees, Research Funding; Shire: Other; Otsuka Pharmaceutical: Other: Personal fees; Teijin Pharma: Research Funding; MSD: Research Funding; Asahi kasei: Research Funding; Eli Lilly: Research Funding; Huya Japan: Other: Personal fees.

Background: Tazemetostat is a selective, reversible, small-molecule inhibitor of enhancer of zest homolog 2 (EZH2), a histone methyltransferase. EZH2 is the catalytic subunit of polycomb repressive complex 2, which methylates lysine 27 on histone 3 (H3K27). Recurrent gain-of-function alterations in EZH2 occur in approximately 30% of germinal center B-cell like diffuse large B-cell lymphoma (GCB-DLBCL) and 27% of follicular lymphoma (FL). The aim of this multicenter, open-label, Phase 2 study was to assess the efficacy and safety of tazemetostat in Japanese patients with relapsed or refractory B-cell Non-Hodgkin's Lymphoma (NHL) harboring the EZH2 mutation. Methods: Patients with histologically diagnosed FL (cohort 1) or DLBCL (cohort 2) were screened centrally for EZH2 mutation using the cobas EZH2 Mutation Test. Tazemetostat (800 mg BID) was administered orally for 28 days/cycle until disease progression, occurrence of unacceptable toxicity, or withdrawal of consent. The primary endpoint was the objective response rate (ORR) based on IWG-2007 by independent imaging review and safety was evaluated as the secondary endpoint. Results: Among the 20 eligible patients, 17 were enrolled in cohort 1, and 3 were enrolled in cohort 2. In cohort 1, the median number of prior chemotherapy was 2 (range 1-4) and the ORR was 76.5% , including 6 patients (35.3%) achieving a complete response and 7 patients (41.2%) achieving a partial response (PR) as of the data cutoff. The ORR in subjects who received prior treatment with bendamustine, rituximab, and CHOP was 87.5%, 76.9%, and 76.9%, respectively. All 3 patients in cohort 2 (100%) achieved PR. In cohort 1, 3 of the 17 subjects (17.6%) had progression-free survival (PFS) events. The median PFS was not reached. Estimated PFS rates at 12 and 15 months based on the Kaplan-Meier analysis were 94.1% and 73.2%, respectively. The median duration of response (DOR) was not reached, and the DOR rate at 9 and 12 months was 100% and 80.0%, respectively. The median time to response was 3.6 months. The most common grade-3 treatment emergent adverse event (TEAE) was lymphopenia (2 patients, 10.0%). Grade-4 TEAEs included hypertriglyceridemia and pneumonia aspiration (1 patient each, 5.0%). TEAEs leading to study drug discontinuation were reported by 4 of 20 (20.0%) patients, including fatigue (2 patients, 10.0%), atypical pneumonia, traumatic intracranial haemorrhage, non-small cell lung cancer, muscle spasticity, and dysgeusia (1 patient each, 5.0%), indicating that the safety profile was acceptable and manageable. Conclusion: Tazemetostat at a dose of 800 mg BID showed encouraging efficacy in patients with relapsed or refractory EZH2 mutation-positive FL with an acceptable safety profile in the overall population. Thus, tazemetostat may be a potential option for the treatment of relapsed or refractory EZH2 mutation-positive FL. Citation Format: Shinya Rai, Kiyoshi Ando, Akifumi Takaori-Kondo, Hirohiko Shibayama, Takanori Teshima, Junya Kuroda, Koji Kato, Yoshitaka Imaizumi, Kisato Nosaka, Rika Sakai, Tadashi Nakanishi, Seiichiro Hojo, Koji Izutsu. Phase 2 study of tazemetostat in Japanese patients with relapsed or refractory EZH2 mutation-positive B-cell Non-Hodgkin's Lymphoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr CT176.

Western blotting (WB) for human T cell leukemia virus type 1 (HTLV-1) is performed to confirm anti-HTLV-1 antibodies detected at the initial screening of blood donors and in pregnant women. However, the frequent occurrence of indeterminate results is a problem with this test. We therefore assessed the cause of indeterminate WB results by analyzing HTLV-1 provirus genomic sequences. A quantitative PCR assay measuring HTLV-1 provirus in WB-indeterminate samples revealed that the median proviral load was approximately 100-fold lower than that of WB-positive samples (0.01 versus 0.71 copy/100 cells). Phylogenic analysis of the complete HTLV-1 genomes of WB-indeterminate samples did not identify any specific phylogenetic groups. When we analyzed the nucleotide changes in 19 HTLV-1 isolates from WB-indeterminate samples, we identified 135 single nucleotide substitutions, composed of four types, G to A (29%), C to T (19%), T to C (19%), and A to G (16%). In the most frequent G-to-A substitution, 64% occurred at GG dinucleotides, indicating that APOBEC3G is responsible for mutagenesis in WB-indeterminate samples. Moreover, interestingly, five WB-indeterminate isolates had nonsense mutations in Pol and/or Tax, Env, p12, and p30. These findings suggest that WB-indeterminate carriers have low production of viral antigens because of a combination of a low proviral load and mutations in the provirus, which may interfere with host recognition of HTLV-1 antigens.

Cell adhesion molecule 1 (CADM1) is a cell adhesion molecule that is expressed in brain, liver, lung, testis, and some kinds of cancer cells including adult T-cell leukemia/lymphoma (ATLL). Recent studies have indicated the involvement of CADM1 in cell-cell contact between cytotoxic T-lymphocytes and virus infected cells. We previously reported that cell-cell interaction between lymphoma cells and macrophages induces lymphoma cell proliferation. In the present study, we investigated whether CADM1 is associated with cell-cell interaction between several human lymphoma cell lines and macrophages. CADM1 expression was observed in the ATLL cell lines, ATN-1, ATL-T, and ATL-35T, and in the B cell lymphoma cell lines, TL-1, DAUDI, and SLVL, using western blotting. Significant cell-cell interaction between macrophages and ATN-1, ATL-T, ATL-35T and MT-2, DAUDI, and SLVL cells, as assessed by induction of cell proliferation, was observed. Immunohistochemical analysis of human biopsy samples indicated CADM1 expression in 10 of 14 ATLL cases; however, no case of follicular lymphoma or diffuse large B-cell lymphoma was positive for CADM1. Finally, the interaction of macrophages with cells of the CADM1-negative ED ATLL cell line and CADM1-transfected ED cells was tested. However, significant cell-cell interaction between macrophage and CADM1-transfected ED cells was not observed. We conclude that CADM1 was not associated with cell-cell interaction between lymphoma cells and macrophages, although CADM1 may be a useful marker of ATLL for diagnostic procedures.

Adult T-cell leukemia/lymphoma (ATL) is an aggressive T-cell malignancy with a dismal prognosis, caused by HTLV-1. Although our previous study, mainly using whole-exome sequencing and SNP array karyotyping, discovered many driver mutations and copy number alterations (CNAs), the whole-genome landscape of ATL still remains elusive. To this end, we have performed high-depth whole-genome sequencing (WGS) of 155 ATL cases with a median sequencing depth of 96-fold for tumors. Among them, 75 cases were also analyzed by RNA sequencing (RNA-seq). In total, we detected 1,952,490 single nucleotide variants (SNVs) and 159,141 insertion-deletions (4.0 SNVs and 0.3 indels/Mb/case), 10,279 SVs (66.3 SVs/case), and 3,975 CN altered segments (25.7 segments/case). Using several driver discovery algorithms (dNdScv, MutSig2CV, and DriverPower), we identified 47 significantly mutated genes, 19 of which were mutated in more than 10% of cases. These included several novel mutations, such as those affecting XPO1 (7.1%), ZNF292 (6.5%), and ITGB1 (5.2%). Using GISTIC2.0, we identified 13 significant CNAs, such as IRF4 amplifications and CDKN2A deletions, consistent with previous SNP array data. To detect significantly recurrent SVs, we calculated SV breakpoint frequency and identified 13 genes affected by SVs, including the previously identified genes (such as CARD11, CD274, and TP73). In addition, we investigated recurrent mutations in non-coding elements by DriverPower and LARVA and discovered 12 recurrently mutated elements. Among them, the most frequent were splice site mutations, including those of HLA-A and HLA-B, most of which caused loss of function as revealed by RNA-seq. By contrast, we found recurrent mutations in TP73 splice site, which induced skipping of exons 2 and 3, generating a dominant-negative variant similar to their SVs. In addition, recurrent non-coding elements contained several novel regions, such as 3´-untranslated region (UTR) of NFKBIZ and 5´- UTR of TMSB4X. Altogether, a total of 56 genes were recurrently altered. The median number of driver alterations was eight per case, and at least one driver alteration was found in 149 cases (96.1%). Among 56 driver genes, 40 (71.4%) genes were affected by more than one alteration class. Some drivers, such as CDKN2A, IKZF2, and CD274, were affected almost exclusively by CNAs and/or SVs, while showing quite high alteration frequencies (11.6-29.0%). These observations suggest that WGS presented a substantially different overview of driver alterations from our previous study. The overall numbers of mutations and SVs were linked to these driver alterations, suggesting their etiology. In particular, inactivation of EP300 and immune-related molecules, such as HLA-A, HLA-B, and CD58, were associated with an increased number of mutations and SVs, especially deletions and tandem duplications. By contrast, cases with TP53-altered cases harbored more inversions and translocations. These results emphasize a pivotal role of immune evasion for acquiring genetic alterations to drive ATL progression. To define molecular subgroups in ATL, we integrated the 56 identified genetic drivers using non-negative matrix factorization clustering and identified two robust subgroups with discrete clinical and genetic characteristics. Group 1 was enriched with alterations affecting distal components of T-cell receptor (TCR)/NF-κB signaling (such as CARD11, PRKCB, and IRF4) and immune-related molecules (HLA-A, HLA-B, and CD58), whereas proximal regulators of TCR/NF-κB signaling (PLCG1, VAV1, and CD28) and a JAK/STAT signaling molecule (STAT3) were more frequently altered in group 2. In addition, group 1 cases had a larger number of mutations, SVs, and CNAs than group 2 cases. Clinically, most cases with lymphoma subtype were classified into group 1, whereas group 2 mainly consisted of cases with leukemic subtypes. Moreover, group1 cases showed a worse overall survival than group 2, independently of clinical subtype. These results suggest the biological and clinical relevance of the molecular classification of ATL. In summary, our WGS analysis not only identifies novel somatic alterations but also extends the overview of ATL genome. We also propose a new molecular classification of ATL, with its clinical relevance, which can lead to the future improvement of patient management. Disclosures Kogure: Takeda Pharmaceutical Company Limited.: Honoraria. Nosaka:Kyowa Kirin Co.Ltd: Honoraria; Chugai pharmaceutical Co. Ltd: Honoraria; Novartis international AG: Honoraria; Celgene K.K: Honoraria; Eisai Co., Ltd: Honoraria; Merck Sharp & Dohme K.K.: Honoraria; Bristol-Myer Squibb: Honoraria. Imaizumi:Kyowa Kirin Co. Ltd.: Honoraria; Bristol-Myers Squibb: Honoraria; Celgene: Honoraria; Eisai: Honoraria. Utsunomiya:Kyowa Kirin: Honoraria; Celgene: Honoraria. Shah:Celgene: Research Funding; BMS: Research Funding; Physicians Education Resource: Honoraria. Janakiram:Takeda, Fate, Nektar: Research Funding. Ramos:NIH: Research Funding. Takaori-Kondo:Astellas Pharma: Honoraria, Research Funding; Celgene: Honoraria, Research Funding; Bristol-Myers Squibb: Honoraria, Research Funding; Kyowa Kirin: Honoraria, Research Funding; Ono Pharmaceutical: Research Funding; Thyas Co. Ltd.: Research Funding; Takeda: Research Funding; CHUGAI: Research Funding; Eisai: Research Funding; Nippon Shinyaku: Research Funding; Otsuka Pharmaceutical: Research Funding; Pfizer: Research Funding; OHARA Pharmaceutical: Research Funding; Sanofi: Research Funding; Novartis Pharma: Honoraria; MSD: Honoraria. Miyazaki:Sumitomo Dainippon Pharma Co., Ltd.: Honoraria; Kyowa Kirin Co., Ltd.: Honoraria; Chugai Pharmaceutical Co., Ltd.: Honoraria; Celgene: Honoraria; NIPPON SHINYAKU CO.,LTD.: Honoraria; Otsuka Pharmaceutical: Honoraria; Novartis Pharma KK: Honoraria; Astellas Pharma Inc.: Honoraria. Matsuoka:Chugai Pharmaceutical Co. Ltd: Research Funding; Bristol-Myers Squibb: Research Funding; Kyowa Kirin Co. Ltd.: Research Funding. Ishitsuka:Takeda: Other: Personal fees, Research Funding; mundiharma: Other: Personal fees; Taiho Pharmaceuticals: Other: Personal fees, Research Funding; Janssen Pharmaceuticals: Other: Personal fees; Novartis: Other: Personal fees; Pfizer: Other: Personal fees; Astellas Pharma: Other, Research Funding; Genzyme: Other; Sumitomo Dainippon Pharma: Other, Research Funding; Eisai: Other, Research Funding; Mochida: Other, Research Funding; Shire: Other; Otsuka Pharmaceutical: Other; Ono Pharmaceutical: Other, Research Funding; Teijin Pharma: Research Funding; MSD: Research Funding; Asahi kasei: Research Funding; Eli Lilly: Research Funding; Daiichi Sankyo: Other; Huya Japan: Other; Celgene: Other: Personal Fees; Kyowa Hakko Kirin: Other: Personal fees, Research Funding; BMS: Other: Personal fees; Chugai Pharmaceutical: Other: Personal fees, Research Funding. Ogawa:Asahi Genomics Co., Ltd.: Current equity holder in private company; Chordia Therapeutics, Inc.: Membership on an entity's Board of Directors or advisory committees, Research Funding; KAN Research Institute, Inc.: Membership on an entity's Board of Directors or advisory committees, Research Funding; Sumitomo Dainippon Pharma Co., Ltd.: Research Funding; Otsuka Pharmaceutical Co., Ltd.: Research Funding; Eisai Co., Ltd.: Research Funding. Shimoda:Takeda Pharmaceutical Company: Honoraria; Bristol-Myers Squibb: Honoraria; Shire plc: Honoraria; Celgene: Honoraria; Perseus Proteomics: Research Funding; PharmaEssentia Japan: Research Funding; AbbVie Inc.: Research Funding; Astellas Pharma: Research Funding; Merck & Co.: Research Funding; CHUGAI PHARMACEUTICAL CO., LTD.: Research Funding; Kyowa Hakko Kirin Co., Ltd.: Research Funding; Pfizer Inc.: Research Funding; Otsuka Pharmaceutical: Research Funding; Asahi Kasei Medical: Research Funding; Japanese Society of Hematology: Research Funding; The Shinnihon Foundation of Advanced Medical Treatment Research: Research Funding; Novartis: Honoraria, Research Funding. Kataoka:CHUGAI PHARMACEUTICAL CO., LTD.: Research Funding; Takeda Pharmaceutical Company: Research Funding; Otsuka Pharmaceutical: Research Funding; Asahi Genomics: Current equity holder in private company.

Background & Aims HBV reactivation is a risk in patients receiving anti-CD20 antibodies for the treatment of lymphoma. The purpose of this post hoc analysis was to evaluate the efficacy of an ultra-high sensitivity HBsAg assay to guide preemptive antiviral treatment in patients with lymphoma and resolved HBV infections using prospectively stored samples from an HBV DNA monitoring study. Methods HBV reactivation (defined as HBV DNA levels of ≥11 IU/ml) was confirmed in 22 of 252 patients. A conventional HBsAg assay (ARCHITECT, cut-off value: 0.05 IU/ml) and an ultra-high sensitivity HBsAg assay employing a semi-automated immune complex transfer chemiluminescence enzyme technique (ICT-CLEIA, cut-off value: 0.0005 IU/ml) were performed at baseline, at confirmed HBV reactivation and monitored after HBV reactivation. Results Baseline HBsAg was detected using ICT-CLEIA in 4 patients; in all of whom precore mutants with high replication capacity were reactivated. Of the 6 patients with HBV DNA detected below the level of quantification at baseline, 5 showed HBV reactivation and 3 of the 5 had precore mutations. Sensitivity for detection by ARCHITECT and ICT-CLEIA HBsAg assays at HBV reactivation or the next sampling after HBV reactivation was 18.2% (4 of 22) and 77.3% (17 of 22), respectively. Of the 5 patients undetectable by ICT-CLEIA, HBV reactivation resolved spontaneously in 2 patients. All 6 patients reactivated with precore mutations including preS deletion could be diagnosed by ICT-CLEIA HBsAg assay at an early stage of HBV reactivation. Multivariate analysis showed that an anti-HBs titer of less than 10 mIU/ml, HBV DNA detected but below the level of quantification, and HBsAg detected by ICT-CLEIA at baseline were independent risk factors for HBV reactivation (adjusted hazard ratios, 15.4, 31.2 and 8.7, respectively; p Conclusions A novel ICT-CLEIA HBsAg assay is an alternative method to diagnose HBV reactivation. Clinical trial number UMIN000001299. Lay summary Hepatitis B virus can be reactivated in lymphoma patients receiving anti-CD20 antibodies such as rituximab. Currently, reactivation requires the monitoring of HBV DNA, but monitoring of the surface antigen (HBsAg) could provide a relatively inexpensive, quick and easy alternative. We assessed the performance of an ultra-high sensitivity HBsAg assay and showed that it could be effective for the diagnosis and monitoring of HBV reactivation.

The retrovirus HTLV-1 integrates into the host cellular DNA, achieves persistent infection, and induces human diseases. Here we demonstrate that viral DNA-capture-seq is useful to characterize HTLV-1 provirus in naturally virus-infected individuals, providing comprehensive information about the proviral structure and the viral integration site. We analyzed peripheral blood from 98 naturally HTLV-1-infected individuals and found that defective proviruses were present not only in patients with leukemia, but also in those with other clinical entities. We further demonstrated that infected clones with defective-type exhibited higher degree of clonal abundance than those with full-length type. The frequency of defective-type in HTLV-1-infected humanized mice was lower than that in infected individuals, indicating that defective proviruses were rare at the initial phase of infection but preferentially selected during persistent infection. These results demonstrate robustness of viral DNA-capture-seq for HTLV-1 infection and shed light on its potential application for other virus-associated cancers in human.

TAFRO syndrome is a rare variant type of multicentric Castleman disease, which is characterized by thrombocytopenia, anasarca, reticulin fibrosis of bone marrow, renal dysfunction and organomegaly. Here, we report a case of TAFRO syndrome that was successfully treated with tocilizumab. A 50-year-old man, who presented with fever, epigastric pain, abdominal fullness, and massive edema of the extremities, was admitted to our hospital. Computed tomography revealed bilateral pleural effusions, ascites, and lymphadenopathy. Laboratory data showed renal dysfunction, anemia, and thrombocytopenia. Examination of bone marrow and cervical lymph nodes led to a diagnosis of hyaline vascular-type Castleman disease. The level of serum interleukin (IL)-6 was extremely high. TAFRO syndrome was finally diagnosed. The patient was treated weekly with tocilizumab, an anti-IL-6 receptor antibody and steroids. In 4 weeks, all symptoms disappeared and serum IL-6 level returned to normal. Activity of ADAMTS13 (a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13), which was significantly decreased (9.9 %) prior to treatment, increased after treatment with tocilizumab. The present case suggests that tocilizumab is an effective therapeutic agent for TAFRO syndrome. We suggest that hypercytokinemia in TAFRO syndrome inhibits ADAMTS13 activity, thereby inducing thrombotic microangiopathy.

Summary Background Patients with adult T-cell leukaemia-lymphoma have few treatment options after relapse and poor survival outcomes with current therapies. We aimed to determine the maximum tolerated dose of lenalidomide, an oral immunomodulator, in Japanese patients with relapsed adult T-cell leukaemia-lymphoma and other peripheral T-cell lymphomas. Methods In this phase 1 study, we enrolled patients aged 20 years or older with Eastern Cooperative Oncology Group performance status 0–2, documented diagnosis of aggressive adult T-cell leukaemia-lymphoma or other peripheral T-cell lymphoma subtypes, and at least one previous antilymphoma therapy. Patients were sequentially assigned to lenalidomide 25 mg/day, days 1–21 of a 28-day cycle (cohort 1), 25 mg/day continuously (cohort 2), and 35 mg/day continuously (cohort 3) in a 3 + 3 design. The primary study endpoint was to identify the maximum tolerated dose of lenalidomide. Analyses were performed per protocol for efficacy and in the intent-to-treat patient population for safety. This completed trial is registered with ClinicalTrials.gov, number NCT01169298. Findings We enrolled 14 patients from six centres in Japan. Of 13 assessable patients (nine with adult T-cell leukaemia-lymphoma, four with other peripheral T-cell lymphomas) receiving lenalidomide, dose-limiting toxic effects were reported in three patients during cycle 1 (one grade 4 thrombocytopenia [cohort 2], one grade 3 QT prolongation on electrocardiogram [cohort 3], and one grade 3 fatigue and grade 4 thrombocytopenia [cohort 3]). The maximum tolerated dose was identified as lenalidomide 25 mg/day given continuously. The most common grade 3 or worse adverse events were neutropenia (eight [62%] patients), lymphopenia (seven [54%] patients), and thrombocytopenia (four [31%] patients); myelosuppression was similar in each cohort. Serious adverse events occurred in eight (62%) patients; thrombocytopenia, which occurred in three (23%) patients, was the only serious adverse event reported in more than one patient. Interpretation We were able to determine the dose and schedule for lenalidomide treatment in previously treated patients with aggressive, adult T-cell leukaemia-lymphoma. This dose will be used in a subsequent phase 2 study. Funding Celgene Corporation.

Quantitative PCR (qPCR) of human T-cell leukemia virus type 1 (HTLV-1) provirus is used for HTLV-1 testing and for assessment of risk of HTLV-1-related diseases. In this study, a reference material was developed for standardizing HTLV-1 qPCR. Freeze-dried TL-Om1 cells diluted with Jurkat cells were prepared and an assigned value for proviral load (PVL) of 2.71 copies/100 cells was determined by digital PCR. Nine Japanese laboratories using their own methods evaluated the PVLs of this reference material as 1.08-3.49 copies/100 cells. The maximum difference between laboratories was 3.2-fold. Correcting measured PVLs by using a formula incorporating the assigned value of this reference material should minimize such discrepancies.

BACKGROUND: Initial results from the ongoing GALLIUM trial have shown that patients with follicular lymphoma have a longer progression-free survival after first-line immunochemotherapy with obinutuzumab than with rituximab. The aim of this secondary analysis was to evaluate the prognostic value of PET-CT responses after first-line immunochemotherapy in the GALLIUM study.METHODS: GALLIUM is an open-label, parallel-group randomised, phase 3 trial, which recruited previously untreated patients with CD20-positive follicular lymphoma (grades 1-3a; disease stage III/IV, or stage II with largest tumour diameter ≥7 cm) who were aged 18 years or older and met the criteria for needing treatment. Eligible patients were randomly assigned in a 1:1 ratio to receive intravenous administration of obinutuzumab (1000 mg on days 1, 8, and 15 of cycle 1, then day 1 of subsequent cycles) or rituximab (375 mg/m2 on day 1 of each cycle), in six 21-day cycles with cyclophosphamide, doxorubicin, vincristine, and prednisone (known as CHOP; oral administration) followed by two 21-day cycles of antibody alone, or eight 21-day cycles cyclophosphamide, vincristine, and prednisone (known as CVP; oral administration), or six 28-day cycles with bendamustine, followed by maintenance antibody every 2 months for up to 2 years. The primary endpoint of the trial, investigator-assessed progression-free survival, has been reported previously. This secondary analysis reports PET and CT-based responses at end-of-induction therapy and explains their relation with progression-free and overall survival outcomes in patients with available scans. As per protocol, during the trial, PET scans (mandatory in the first 170 patients enrolled at sites with available PET facilities, and optional thereafter), acquired at baseline and end of induction (PET population), were assessed prospectively by investigators and an independent review committee (IRC) applying International Harmonisation Project (IHP) 2007 response criteria, and retrospectively by the IRC only applying current Lugano 2014 response criteria. IRC members (but not study investigators) were masked to treatment and clinical outcome when assessing response. The landmark analyses excluded patients who died or progressed (contrast enhanced CT-based assessment of progressive disease, or started next anti-lymphoma treatment) before or at end of induction. GALLIUM is registered at ClinicalTrials.gov, number NCT01332968.FINDINGS: 1202 patients were enrolled in GALLIUM between July 6, 2011, and Feb 4, 2014, of whom 595 were included in the PET population; 533 (IHP 2007; prospective analysis), and 508 (Lugano 2014; retrospective analysis) were analysed for progression-free survival (landmark analysis). At end of induction, 390 of 595 patients (65·5% [95% CI 61·6-69·4]) achieved PET complete response according to IHP 2007 criteria, and 450 (75·6% [95% CI 72·0-79·0]) obtained PET complete metabolic response according to Lugano 2014 criteria. With a median of 43·3 months of observation (IQR 36·2-51·8), 2·5-year progression-free survival from end of induction was 87·8% (95% CI 83·9-90·8) in PET complete responders and 72·0% (63·1-79·0) in non-complete responders according to IRC-assessed IHP 2007 criteria (hazard ratio [HR] 0·4, 95% CI 0·3-0·6, pINTERPRETATION: Our results suggest that PET is a better imaging modality than contrast-enhanced CT for response assessment after first-line immunochemotherapy in patients with follicular lymphoma. PET assessment according to Lugano 2014 response criteria provides a platform for investigation of response-adapted therapeutic approaches. Additional supportive data are welcomed.FUNDING: F Hoffmann-La Roche.