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A 76-year-old man presented with skin plaque and splenic nodules, and diffuse large B-cell lymphoma (DLBCL) with infiltration of T-cells was suspected based on the skin lesions. The disease showed indolent clinical behavior for three months, when systemic lymphadenopathy rapidly evolved. An inguinal lymph node biopsy revealed DLBCL with abundant infiltration of T follicular helper (TFH) cells. A polymerase chain reaction-based analysis of immunoglobulin variable heavy chain showed that the skin, splenic nodules, and inguinal lymph node shared the same clone. This case indicates that the dysregulated infiltration of TFH cells in the tumor microenvironment accelerates the lymphomagenesis and progression of DLBCL.

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.

Background The International Myeloma Working Group response criteria require two consecutive assessments of paraprotein levels. We conducted an exploratory analysis to evaluate whether a single response assessment could be a substitute for the International Myeloma Working Group criteria using data from JCOG1105, a randomized phase II study on melphalan, prednisolone and bortezomib. Methods Of 91 patients with transplant-ineligible newly diagnosed multiple myeloma, 79 patients were included. We calculated the kappa coefficient to evaluate the degree of agreement between the International Myeloma Working Group criteria and the single response assessment. Results Based on the International Myeloma Working Group criteria, 11 (13.9%), 20 (25.3%), 36 (45.6%) and 12 (15.2%) patients had stringent complete response/complete response, very good partial response, partial response and stable disease, respectively. Based on the single response assessment, 17 (21.5%), 19 (24.1%), 35 (44.3%) and 8 (10.1%) patients had stringent complete response/complete response, very good partial response, partial response and stable disease, respectively. The kappa coefficient was 0.76 (95% confidence interval, 0.65–0.88), demonstrating good agreement. The single response assessment was not inferior to the International Myeloma Working Group criteria in the median progression-free survival (3.8 and 2.9 years) in stringent complete response/complete response patients, suggesting that the single response assessment was not an overestimation. Conclusions The single response assessment could be a substitute for the current International Myeloma Working Group criteria for transplant-ineligible newly diagnosed multiple myeloma., The single response assessment could be a substitute for the current International Myeloma Working Group criteria with two consecutive assessments in patients with transplant-ineligible newly diagnosed multiple myeloma.

Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph + ALL) is an aggressive leukemia that occurs in 20-40% of adult patients. Ph + ALL is caused by the Philadelphia chromosome (Ph), which consists of a t(9;22)(q34;q11) reciprocal translocation leading to the formation of a BCR-ABL1 fusion gene. The disease is treated with targeted therapy comprising ABL1 tyrosine kinase inhibitors (TKIs). Ponatinib is a third generation TKI that demonstrates higher binding affinity for ABL1 than first/second generation TKIs. Although intensive combined immunotherapy with ponatinib greatly improves the prognosis of Ph + ALL, the safety and efficacy profiles of ponatinib in Japanese patients are unclear. This retrospective study investigated five cases of Ph + ALL at a single institute to evaluate safety and efficacy profiles. Three patients achieved a deep molecular response (DMR) following combined intensive treatment with ponatinib as induction chemotherapy. Four patients received consolidative allogenic stem cell transplantation (allo-SCT) during their first complete response. Three of the four experienced early relapse within 100 days; they subsequently received ponatinib, and one of the three achieved a DMR. No patient experienced severe cardiovascular events. This case series suggests that ponatinib at a concentration of least 30 mg exhibits anti-leukemia effects in Japanese patients with Ph + ALL.

Recently, allogeneic peripheral blood stem cell transplantation from human leukocyte antigen (HLA)-haploidentical donors using post-transplantation cyclophosphamide (PTCY-haploPBSCT) has become available in clinical practice. However, the efficacy of PTCY in adult T-cell leukemia (ATL) is not fully established yet. In this study, we retrospectively examined data of seven patients who underwent PTCY-haploPBSCT. The overall survival rate at 100 days after transplantation was 85.7%, and the 1-year overall survival rate was 68.6%. The cumulative incidence of relapse at 1 year was 31.4%, whereas the 1-year nonrelapse mortality was 17.1%. The cumulative incidence of grade III-IV acute graft-versus-host disease (GVHD) on day 100 was 14.3%, and the incidence of chronic GVHD at 1 year was 33.3%. These results suggest that PTCY-haploPBSCT can be a viable option even in patients with ATL. Further accumulation of knowledge and improvement of transplantation outcomes are warranted in the future.

Patients with FMS-like tyrosine kinase 3 internal tandem duplication (FLT3-ITD) acute myeloid leukemia (AML) respond to conventional induction chemotherapy, with remission rates similar to those seen in other subtypes; however, they are much more likely to relapse and relapse is rapid. For this reason, eligible patients receive consolidation therapy with early allogenic transplantation, but the recurrence rate remains high, even after transplantation. Moreover, the optimal therapy for patients with FLT3-ITD AML who relapse after allogeneic hematopoietic stem cell transplantation remains unclear. Here, we report a case in which graft-versus-leukemia (GVL) effects were induced by gilteritinib administration after a second transplant from the same donor, resulting in sustained remission of early FLT3-ITD AML relapse after allogeneic transplantation. Several studies suggest that the benefits of FLT3 tyrosine kinase inhibitors (FLT3-TKI) after allogeneic transplantation are attributable to GVL induction, as well as direct effects on FLT3 mutation-positive leukemia cells. With this in mind, we induced lymphodepletion using L-PAM to further enhance GVL induction by donor lymphocytes and FLT3-TKI. We believe that enhancement of GVL induction by lymphodepletion should be considered before FLT3-TKI use, if the prognosis is very poor, such as in patients with recurrence following allogeneic transplantation.

Background: Cancer genome profiling using next-generation sequencing (NGS) has become widespread. Multiple genetic abnormalities including variant of unknown significance (VUS) have been detected in various cancer types. However, there is a lack of an integrated analysis system capable of identifying relationships among multiple genetic abnormalities and weighting them appropriately. Here, we report heat map analysis, a new integrated pathway scoring system for cancer genome profiling. Methods: In heat map analysis, approximately 180 cancer-related genes among 324 genes evaluated by FoundationOne CDxTM are scored based on gene annotation and variant allele fraction (VAF), and classified into 16 pathways. This system provides an overall picture of genetic abnormalities and easy recognition of abnormal pathways. To examine the usefulness of the heat map analysis, a retrospective observational study was conducted on 50 patients with solid tumors who underwent cancer genome profiling test at Saga University Hospital from June 2019 to February 2022. The primary end point was the presentation rate of pathways with significantly increased scores. Results: A total of 749 genetic abnormalities including VUS were detected in 50 patients with 15 cancer types: 571 single nucleotide variants (SNVs), 156 copy number variants (CNVs), and 22 fusions. The median number of abnormalities detected was 11 (2-20) SNVs, 2 (0-23) CNVs, and 0 (0-4) fusions, respectively. Heat map analysis presented active pathways with significant score elevation in 42 cases (84%). The TP53 pathway was the most common, followed by the Receptor Tyrosine Kinase pathway, PIK3-AKT, RAS, and DNA repair-related pathways. Conclusion: Heat map analysis could be a promising new method for integrated analysis using cancer genome profiling tests. Citation Format: Chiho Nakashima, Yukimasa Shiotsu, Yohei Harada, Hiroo Katsuya, Emi Ookuma, Masanori Nishi, Akemi Sato, Hideaki Nakamura, Naoko Sueoka-Aragane. Heat Map Analysis, a new integrated pathway scoring system for cancer genome profiling [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 262.

A 54-year-old woman was diagnosed with acute adult T-cell leukemia (ATL) in November 2015 and underwent allogeneic hematopoietic stem cell transplantation in March 2016. Cognitive impairment appeared suddenly around May 2019, and MRI of the brain showed cerebral white matter lesions. Cerebrospinal fluid examination showed no significant findings other than elevated protein. Brain biopsy showed inflammatory cells, (mainly CD8-positive T lymphocytes), infiltrating the white matter. Based on the pathological findings and the history of chronic graft versus host disease (GVHD) in the lungs and intestines, we diagnosed central nervous system involvement of GVHD (CNS-GVHD). Immunotherapy with steroids and mycophenolate mofetil resulted in improvement of the cognitive dysfunction and inflammatory findings in the spinal fluid. This case is the first report of CNS-GVHD in ATL, suggesting the importance of diagnosis by brain biopsy and the efficacy of immunotherapy.

The mainstream first-line chemotherapy for advanced/recurrent gastric cancer (ARGC) is combination therapy including platinum-based agents. With the progressive aging of the society, the incidence of gastric cancer in elderly patients is increasing. However, elderly patients cannot tolerate these agents because of renal dysfunction or low quality of life. The KSCC1701 study explored the efficacy and safety of S-1 + ramucirumab in elderly patients with ARGC.Chemotherapy-naive patients aged ≥70 years with ARGC were eligible. Patients received S-1 (40-60 mg twice daily for 4 weeks in 6-week cycles) and ramucirumab (8 mg/kg every 2 weeks) until disease progression. The primary end-point was the 1-year overall survival (OS) rate. The anticipated lower threshold of 1-year survival was set at 40% in light of previous S-1-based regimens. The secondary end-points included progression-free survival (PFS), OS, the overall response rate (ORR) and safety.Between September 2017 and November 2019, 48 patients (34 men and 14 women) were enrolled in this study. The median patient age was 77.5 years, and all patients had a performance status of 0 (n = 20) or 1 (n = 28). The 1-year OS rate was 65.2%, which met the primary end-point. The median survival time and median PFS were 16.4 and 5.8 months, respectively. The ORR was 41.9%. The most frequent grade 3/4 (≥15%) adverse events were neutropenia, anorexia and anaemia.Considering these findings, S-1 + ramucirumab appears to be an excellent treatment option for elderly patients with ARGC. (250 words). This trial has been registered with the Japan Registry of Clinical Trials Registry under the number jRCTs071180066.

Human T-cell leukemia virus type 1 (HTLV-1) mainly infects CD4+T-cells and induces chronic, persistent infection in infected individuals with some progressing to develop adult T-cell leukemia/lymphoma (ATL). Whilst HTLV-1 alters cellular differentiation, activation and survival, it is unknown whether and how these changes contribute to malignant transformation of infected T-cells. In this study, we used single-cell RNA-Seq and TCR-Seq to investigate T-cell differentiation and HTLV-1-mediated transformation processes. We analyzed 87,742 single cells from peripheral blood of 12 infected and 3 uninfected individuals. Using multiple independent bioinformatic methods, we demonstrated that naïve T-cells dynamically change into activated T-cells including infected cells, which seamlessly transitioned into ATL cells characterized by clonally expanded, highly-activated T-cells. Notably, the more activated ATL cells are, the more they acquire Treg signatures. Intriguingly, HLA class II genes were uniquely induced in infected cells, further upregulated in ATL cells and was induced by viral protein Tax. Functional assays revealed that by upregulating HLA class II, HTLV-1-infected cells can act as tolerogenic antigen presenting cells (APCs) to induce anergy of antigen specific T-cells. In conclusion, our study revealed the in vivo mechanisms of HTLV-1-mediated transformation and immune escape at single-cell level.Graphical Abstract

Discontinuation of tyrosine kinase inhibitors (TKIs) is now a feasible therapeutic goal for patients with chronic phase chronic myeloid leukemia (CML-CP). Whereas approximately half of patients experience molecular relapse, after resuming with any TKI; the majority re-achieve a deep molecular response (DMR). It is unclear whether such patients who re-achieve a durable DMR can discontinue TKI safely again. Here, we retrospectively assessed first, second, and third attempts to stop TKIs in patients with CML-CP. At the first attempt, 28 out of a total of 53 patients achieved sustained treatment-free remission (TFR; 53.4%; 95% confidence interval [CI], 39.0%-65.9%). Subsequently, 10 of 25 patients attempted a second TKI discontinuation, and in all cases, this was after receiving second-generation TKIs. Four of 10 patients successfully achieved TFR (37.5%; 95% CI, 9.9%-65.9%). All patients who relapsed at the second TKI discontinuation attempt were re-administered TKIs, and soon achieved at least a major molecular remission. All six second relapse patients had a loss of MR4.5 at 3 months after TKI discontinuation. These findings suggest that second and third attempts to successfully stop TKI treatment are feasible in patients with CML-CP.

Cronkhite-Canada syndrome (CCS) is a rare polyposis disorder accompanied by alopecia and onychodystrophy. A 63-year-old man with a history of CCS and repeated embolism developed progressive thrombocytopenia and mild anemia. Laboratory testing, a bone marrow examination, and magnetic resonance imaging of the spine resulted in a diagnosis of concurrent aplastic anemia (AA). Paroxysmal nocturnal hemoglobinuria (PNH)-type cells were detected in a peripheral blood specimen. In addition, human leukocyte antigen (HLA) included DRB1*15:01 and DRB1*15:02. Mesalazine was discontinued in consideration of possible drug-induced pancytopenia. Immunosuppressive therapy ameliorated both the gastrointestinal symptoms of CCS and pancytopenia. A common autoimmune abnormality might underlie both CCS and AA.

Human T cell leukemia virus type 1 (HTLV-1) mainly infects CD4(+) T cells and induces chronic, persistent infection in infected individuals, with some developing adult T cell leukemia/lymphoma (ATL). HTLV-1 alters cellular differentiation, activation, and survival; however, it is unknown whether and how these changes contribute to the malignant transformation of infected cells. In this study, we used single-cell RNA-sequencing and T cell receptor–sequencing to investigate the differentiation and HTLV-1–mediated transformation of T cells. We analyzed 87,742 PBMCs from 12 infected and 3 uninfected individuals. Using multiple independent bioinformatics methods, we demonstrated the seamless transition of naive T cells into activated T cells, whereby HTLV-1–infected cells in an activated state further transformed into ATL cells, which are characterized as clonally expanded, highly activated T cells. Notably, the greater the activation state of ATL cells, the more they acquire Treg signatures. Intriguingly, the expression of HLA class II genes in HTLV-1–infected cells was uniquely induced by the viral protein Tax and further upregulated in ATL cells. Functional assays revealed that HTLV-1–infected cells upregulated HLA class II molecules and acted as tolerogenic antigen-presenting cells to induce anergy of antigen-specific T cells. In conclusion, our study revealed the in vivo mechanisms of HTLV-1–mediated transformation and immune escape at the single-cell level.

Background Coinfection with human immunodeficiency virus type 1 (HIV-1) and human T-cell leukemia virus type 1 (HTLV-1) diminishes the value of the CD4+ T-cell count in diagnosing AIDS, and increases the rate of HTLV-1–associated myelopathy. It remains elusive how HIV-1/HTLV-1 coinfection is related to such characteristics. We investigated the mutual effect of HIV-1/HTLV-1 coinfection on their integration sites (ISs) and clonal expansion. Methods We extracted DNA from longitudinal peripheral blood samples from 7 HIV-1/HTLV-1 coinfected, and 12 HIV-1 and 13 HTLV-1 monoinfected individuals. Proviral loads (PVL) were quantified using real-time polymerase chain reaction (PCR). Viral ISs and clonality were quantified by ligation-mediated PCR followed by high-throughput sequencing. Results PVL of both HIV-1 and HTLV-1 in coinfected individuals was significantly higher than that of the respective virus in monoinfected individuals. The degree of oligoclonality of both HIV-1– and HTLV-1–infected cells in coinfected individuals was also greater than in monoinfected subjects. ISs of HIV-1 in cases of coinfection were more frequently located in intergenic regions and transcriptionally silent regions, compared with HIV-1 monoinfected individuals. Conclusions HIV-1/HTLV-1 coinfection makes an impact on the distribution of viral ISs and clonality of virus-infected cells and thus may alter the risks of both HTLV-1– and HIV-1–associated disease.

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.

Background The UK Myeloma Research Alliance Risk Profile (MRP) (Lancet Haematol 2019) was developed as a prognostic score for transplant-ineligible, newly diagnosed multiple myeloma (NDMM) patients. MRP consists of widely available clinical parameters, such as WHO performance status (PS), International Staging System (ISS), age, and C-reactive protein (CRP) level. However, as MRP was developed in clinical trials in which immunomodulatory drugs were used as induction regimens, its applicability to patients who were treated with bortezomib (BOR)-based regimens remains elusive. We conducted an exploratory analysis to assess the utility of MRP using data from JCOG1105, a randomized phase II trial in which two modified MPBs (melphalan, prednisolone, and BOR) were compared (Br J Haematol 2021). Furthermore, the clinical factors associated with poor outcomes among patients included in JCOG1105 were evaluated. Methods The data of 88 transplant-ineligible patients with NDMM enrolled in JCOG1105 between July 2013 and April 2016 were analyzed. Progression-free survival (PFS) and overall survival (OS) in each MRP risk were estimated using the Kaplan-Meier method and compared using the log-rank test. Clinical parameters associated with poor prognosis were evaluated in univariable and multivariable Cox regression analyses. Results The baseline characteristics of the 88 patients were as follows: a median age of 72 (range, 65–79) years, 20 (23%) had PS ≥2, 13 (15%) with LDH > upper normal limit (UNL), and median CRP level of 1 mg/L (range, 0–140). Forty-six (52%) and 16 (18%) patients had ISS II and III disease, respectively. MRP was evaluated in 87 patients (excluding one patient with missing data on CRP levels) and was classified as low (n=51), medium (n=16), and high risk (n=20). With a median follow-up of 47.3 (range, 10.4-71.1) months, the 3-year PFS and OS of all 88 patients were 20.5% (95% confidence interval [CI]: 13–29%) and 81.8% (95% CI: 72–88%), respectively. In patients with MRP low, medium, and high risk, the outcomes were as follows: a 3-year PFS of 26%, 19%, and 10% and a 3-year OS of 84%, 69%, and 85%, respectively. A higher MRP risk was not significantly associated with a poorer PFS and OS. In multivariable analysis, LDH > UNL (Hazard Ratio [HR]: 4.73, 95% CI: 1.71–13.13) and β2MG ≥ 3.5 mg/dL (HR: 2.86, 95% CI: 1.20–6.81) were significantly associated with poor OS. PS ≥2 was not associated with poor OS (HR: 0.85, 95% CI: 0.33–2.23). Conclusion Higher MRP risk scores were not significantly associated with poor outcomes in patients who received MPB in this exploratory analysis. Large-scale studies aimed at evaluating the applicability of MRP in NDMM patients treated with BOR-based regimens are needed.

Persistence of HIV-1 latent reservoir cells during antiretroviral therapy is a major obstacle for curing HIV-1. Latency-reversing agents (LRAs) are under development to reactivate and eradicate latently infected cells; however, there are few useful models for evaluating LRA activity in vitro . Here we established a long-term cell culture system harboring thousands of different HIV-1-infected cell clones with a wide distribution of HIV-1 provirus similar to that observed in vivo . A combination of an LRA and antiretroviral therapy (ART) significantly reduced viral rebound upon treatment interruption. Experimental results and mathematical modeling demonstrated that addition of LRA to ART showed latency-reversing effect and contributed to the eradication of replication competent HIV-1. The widely distributed intact provirus elimination (WIPE) assay can be used to optimize therapeutic against HIV-1 latency and investigate mechanistic insights into the clonal selection of heterogeneous HIV-1-infected cells.

Membranous nephropathy (MN) is a common glomerular disease that is characterized by diffuse thickening of the glomerular basement membrane, and a common cause of nephrotic syndrome (NS). MN is often accompanied with malignant disease; The solid tumors are commonly associated with MN, whereas hematological malignancies are rarely found in patients with MN. A 68-year-old man with a history of diabetes mellitus visited a hospital with a chief complaint of general fatigue. He was previously not diagnosed with any complications of diabetes. Computed tomography revealed a pancreatic tumor, and the pathological findings of the biopsied tumor revealed the tumor was diffuse large B-cell lymphoma (DLBCL). Concurrently, he developed severe proteinuria, hypoalbuminemia, systemic edema and hyperlipidemia, consistent with the diagnosis of NS. The biopsied renal specimen revealed minute spike lesions of glomerular basement membrane, and abnormal lymphocytes infiltrated in the kidney interstitially. Anti-glomerular basement membrane antibody, proteinase-3-/myeloperoxidase antineutrophil cytoplasmic antibody and hepatitis B antigenemia, are absent in the patient. Serum anti-phospholipase A2 receptor (PLA2R) antibody (marker for primary MN) was not detected. A diagnosis of secondary MN induced by DLBCL was made. He received rituximab containing chemotherapy for DLBCL, resulting in amelioration of both DLBCL and MN. We report the rare case of a patient co-existing NS and DLBCL. DLBCL might be pathogenesis of NS; the findings are supported by the presence of MN, an underlying malignancy (DLBCL), and the lack of anti-PLA2R antibodies. Although further investigation is warranted, our case suggests that DLBCL is a possible cause of secondary MN.

306 Background: The combination of paclitaxel (PTX) plus ramucirumab (RAM) has been the standard regimen for advanced gastric cancer (GC) or gastro-esophageal junction cancer (GJC) patients (pts) who were treated with fluoropyrimidine-containing regimen. In a phase 2 trial, it was showen that nab-PTX plus RAM has promising activity (objective response rate [ORR], 55 %; median progression free survival [PFS], 7.6 months) [Bando H, et al. Eur J Cancer 2018] and is, therefore, a treatment option. However, high incidence of myelosuppression led to discontinuation of the nab-PTX. Therefore, we conducted this study to investigate whether schedule modification to biweekly nab-PTX plus RAM therapy is safe and effective. Methods: Pts with GC or GJC treated with fluoropyrimidine-containing regimen were enrolled and received nab-PTX (100 mg/m2) on days 1, 8, and 15 and RAM (8 mg/kg) on days 1 and 15 of a 28-day cycle. The treatment schedule of pts with severe myelosuppression during the first cycle was modified to biweekly therapy from the second cycle. The primary endpoint was PFS in modified pts. Secondary endpoints included ORR, disease control rate (DCR), overall survival (OS), and safety. The exploratory analysis evaluated PFS and OS in pts who continued standard-schedule therapy. Based on the hypothesis that biweekly nab-PTX plus RAM therapy would improve PFS from 4.5 months to 7.0 months, 40 pts were required for a power of 0.8 with a one-sided α of 0.05. Results: Of the 81 pts who were enrolled, 76 pts received standard nab-PTX plus RAM in the first cycle and 47 pts (58%) were modified to the bi-weekly therapy. Pts characteristics in the modified pts were as follows: median age, 70 years; male, 72%; ECOG PS 0, 81%; and poorly differentiated adenocarcinoma or signet ring cell carcinoma, 45%. The median relative dose intensities of the entire period and after modification were 66% and 60%, respectively. In the modified pts, median PFS was 4.7 months (95% Confidence Interval [CI]: 3.7–5.6), median OS was 13.9 months (95% CI: 9.1–16.9), ORR was 25% (95% CI: 11–39), and DCR was 75% (95% CI: 61–89). Tumor shrinkage was observed in 61% of the pts (n = 36) with measurable lesion. In pts who could continue standard-schedule therapy, median PFS was 2.7 months (95% CI: 1.8–4.0) and median OS was 8.0 months (95% CI: 5.6–14.7). Severe (Grade >3) adverse events after modification were neutropenia (55%), anemia (13%), hypertension (17%), and peripheral sensory neuropathy (13%). Conclusions: Our study could not meet the primary endpoint for PFS. However, PFS in pts with standard-schedule therapy was numerically lower than that in the modified pts. The modification to biweekly schedule might be considered to be a treatment option for GC/GJC pts with severe myelosuppression in second-line nab-PTX plus RAM therapy. Clinical trial information: jRCTs031180061.

280 Background: Combination of ramucirumab (RAM) + weekly paclitaxel (PTX) is recommended as a standard second-line therapy for unresectable or recurrent gastric cancer (GC). A recent phase II trial evaluating nab-PTX and RAM combination showed that nab-PTX+RAM is promising efficacy and tolerability as well as PTX+RAM. In subgroup analysis of another phase III trial (ABSOLUTE) comparing different nab-PTX scheduling with PTX, weekly nab-PTX was especially effective for the patients with peritoneal dissemination compared to PTX without RAM combination. Therefore, we hypothesized that nab-PTX+RAM would be more effective than PTX+RAM for patients with peritoneal dissemination. Methods: The P-SELECT trial (WJOG10617G) is an open-label randomized phase II study evaluating the safety and efficacy of PTX+RAM and nab-PTX+RAM in GC patients with peritoneal metastasis. Key eligibility criteria were: 1) histologically proven adenocarcinoma, 2) unresectable or recurrent gastric cancer, 3) peritoneal dissemination, 4) intolerance or refractory to first-line therapy including fluoropyrimidines, 5) PS 0–2. Peritoneal dissemination was confirmed by either contrast enema/enterography, CT scan, clinical signs, or operative findings (including exploratory laparoscopy). The primary endpoint was overall survival (OS), and the secondary endpoints were progression-free survival (PFS), objective response rate (ORR), disease control rate (DCR), ascites control rate, safety, and neuropathy-specific quality of life. 105 subjects were required to maintain the power of ≥70% expecting the hazard ratio (HR) of 0.90 in OS. The study was conducted in 58 centers of the West Japan Oncology Group. Results: A total of 105 patients (median age 67; M:F 66:39) were randomized (53 patients in PTX+RAM and 52 in nab-PTX+RAM). Moderate and massive amount of ascites was observed in 39.0% of patients. Median OS was 8.1 months in PTX+RAM and 7.2 months in nab-PTX+RAM (HR 1.04, 95% confidence interval [CI] 0.67–1.61, P = 0.63). Median PFS was 5.1 months in PTX+RAM and 3.9 months in nab-PTX+RAM (HR 1.04, 95% CI 0.69–1.56, P = 0.89). The ORR and DCR for PTX+RAM and nab-PTX+RAM were 20.7% vs. 20.0% (P = 0.99) and 77.4% vs. 63.5% (P = 0.15), respectively. The ascites control rate was 86.1% in PTX+RAM and 70.3% in nab-PTX+RAM (P = 0.07). The incidence of grade 3/4 neuropathy was higher in nab-PTX+RAM (7.5% vs 17.6%, P = 0.14), whereas there was no difference in neuropathy-specific quality of life between the two groups. The incidence of febrile neutropenia was higher in PTX+RAM (11.3% vs 5.9%, P = 0.49). Conclusions: The potential difference in efficacies between nab-PTX+RAM and PTX+RAM was not shown in advanced gastric cancer with peritoneal dissemination. The results of the pre-planned translational research will be available soon. Clinical trial information: jRCTs031180022.

256 Background: KSCC1701 trial showed the efficacy and safety of S-1 plus ramucirumab as a first-line treatment for elderly patients with advanced/recurrent gastric cancer. However, some frail patients may not benefit from S-1 plus ramucirumab. We aimed to clarify the usefulness of G8 screening tool for stratifying the efficacy and safety of S-1 plus ramucirumab therapy to elderly patients with advanced/recurrent gastric cancer. Methods: Patients aged 70 and older with previously untreated unresectable or recurrent gastric cancer were included from 23 institutes in Japan. They received S-1 (40-60 mg twice daily for 28 days, every 6 weeks) plus ramucirumab (8 mg/kg, every 2 weeks) until disease progression. The primary endpoint was the one-year survival rate. The secondary endpoints included progression-free survival (PFS), overall survival (OS), response rate (RR), and safety. The exploratory endpoint was detection of differences in treatment response by G8 screening tool. Results: Between September 2017 and November 2019, 48 patients were enrolled in this study. The cut-off value of G8 was determined as 11 by time-dependent ROC curve analysis for OS. Patients of G8 high (> = 11) and low (< 11) were 31 and 15, respectively. The characteristics of patients with G8 high/low were male: 21 (65.6%)/13 (81.3%), median age: 77/78 years, and PS (0): 16 (50.0%)/4 (25.0%). The one-year survival rate (total/G8-high/G8-low) was 65.2%/82.6%/26.7%. The median OS and PFS (total/G8-high/G8-low) were 16.4/20.7/6.9 months and 5.8/7.2/3.9 months, respectively. On Cox proportional hazards regression analysis for OS and PFS, the hazard ratio of G8-high was 0.156 [95%CI:0.066-0.367 (p < 0.0001)] and 0.391 [95%CI:0.202-0.755 (p = 0.0038)], respectively. The best RR (total/G8-high/G8-low) was 41.9%/55.6%/23.1%. The frequent grade 3 adverse events (total/G8-high/G8-low) was 78.7%/77.4%/81.3%. The frequent grade 4 adverse events (total/G8-high/G8-low) was 14.9%/16.1%/12.5%. Conclusions: Based on the results, G8 screening tool is useful for selecting elderly patients with advanced/recurrent gastric cancer in whom S-1 plus ramucirumab treatment shows a longer survival and a higher RR. Further examination including adverse events is therefore warranted. Clinical trial information: UMIN000028309.

Summary Persistence of HIV-1 latent reservoir cells during antiretroviral therapy (ART) is a major obstacle for curing HIV-1. Even though latency-reversing agents (LRAs) are under development to reactivate and eradicate latently infected cells, there are few useful models for evaluating LRA activity in vitro. Here, we establish a long-term cell culture system called the "widely distributed intact provirus elimination" (WIPE) assay. It harbors thousands of different HIV-1-infected cell clones with a wide distribution of HIV-1 provirus similar to that observed in vivo. Mathematical modeling and experimental results from this in vitro infection model demonstrates that the addition of an LRA to ART shows a latency-reversing effect and contributes to the eradication of replication-competent HIV-1. The WIPE assay can be used to optimize therapeutics against HIV-1 latency and investigate mechanistic insights into the clonal selection of heterogeneous HIV-1-infected cells.

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.

Adult T-cell leukemia-lymphoma (ATL) has been divided into 4 clinical subtypes: acute, lymphoma, chronic, and smoldering. The aim of this study is to develop a novel prognostic index (PI) for chronic and smoldering ATL. We conducted a nationwide retrospective survey on ATL patients, and 248 fully eligible individuals were used in this analysis. In the univariate analysis, sex, performance status, log10 (soluble interleukin-2 receptor [sIL-2R]), neutrophils count, and lymphadenopathy showed values of P < .05 in training samples. A multivariate analysis was performed on these factors, and only log10 (sIL-2R) was identified as an independent prognostic factor in training samples. Using a regression coefficient of this variable, a prognostic model was formulated to identify different levels of risk: indolent ATL-PI (iATL-PI) = 1.51 × log10 (sIL-2R [U/mL]). The values calculated by iATL-PI were divided into 3 groups using a quartile point. In the validation sample, median survival times (MSTs) were 1.6 years, 5.5 years, and not reached for patients in the high-, intermediate-, and low-risk groups, respectively (P < .0001). To make the scoring system clinically practicable, we simplified iATL-PI according to trichotomizing sIL-2R at 1000 and 6000 U/mL, using a quartile point. Patients with more than 6000 U/mL sIL-2R were categorized into the high-risk group, less than and equal to 1000 U/mL into the low-risk group, and the others into the intermediate-risk group, and MSTs were 1.6 years, not reached, and 5.5 years, respectively (P < .0001). iATL-PI has potential as a novel tool for a risk-adapted therapeutic approach.

Persistence of HIV-1 latent reservoir cells during antiretroviral therapy is a major obstacle for curing HIV-1. Latency-reversing agents (LRAs) are under development to reactivate and eradicate latently infected cells; however, there are few useful models for evaluating LRA activity in vitro. Here, we established a long-term cell culture system harboring thousands of different HIV-1-infected cell clones with a wide distribution of HIV-1 provirus similar to that observed in vivo. A combination of an LRA and antiretroviral therapy (ART) significantly reduced viral rebound upon treatment interruption. Experimental investigation and mathematical modeling demonstrated that addition of LRA to ART induced latency-reversing effect and contributed to the eradication of replication competent HIV-1. The widely distributed intact provirus elimination (WIPE) assay will be useful for optimizing therapeutics against HIV-1 latency and investigating mechanistic insights into the clonal selection of heterogeneous HIV-1-infected cells.