Ilseung Choi

Expression of programmed cell death ligand 1 is associated with poor overall survival in patients with diffuse large B-cell lymphoma

Programmed cell death ligand 1 (PD-L1) is expressed on both select diffuse large B-cell lymphoma (DLBCL) tumor cells and on tumor-infiltrating nonmalignant cells. The programmed cell death 1 (PD-1)/PD-L1 pathway inhibits host antitumor responses; however, little is known about how this pathway functions in the tumor microenvironment. The aim of this study was to determine the clinicopathological impact of PD-L1(+) DLBCL. We performed PD-L1/PAX5 double immunostaining in 1253 DLBCL biopsy samples and established a new definition of PD-L1(+) DLBCL. We also defined the criteria for microenvironmental PD-L1(+) (mPD-L1(+)) DLBCL (ie, PD-L1(-) DLBCL in which PD-L1(+) nonmalignant cells are abundant in the tumor microenvironment). Of the 273 patients whose clinical information was available, quantitative analysis of PD-1(+) tumor-infiltrating lymphocytes (TILs) was performed. The prevalence rates of PD-L1(+) and mPD-L1(+) DLBCL were 11% and 15.3%, respectively. Both PD-L1(+) and mPD-L1(+) DLBCL were significantly associated with non-germinal center B-cell (GCB) type and Epstein-Barr virus positivity. The number of PD-1(+) TILs was significantly higher in GCB-type tumors and lower in mPD-L1(-) and PD-L1(+) DLBCL. Patients with PD-L1(+) DLBCL had inferior overall survival (OS) compared with that in patients with PD-L1(-) DLBCL (P = .0009). In contrast, there was no significant difference in OS between mPD-L1(+) and mPD-L1(-) DLBCL (P = .31). The expression of PD-L1 maintained prognostic value for OS in multivariate analysis (P = .0323). This is the first report describing the clinicopathological features and outcomes of PD-L1(+) DLBCL. Immunotherapy targeting the PD-1/PD-L1 pathway should be considered in this distinct DLBCL subgroup.

Multicenter phase II study of bendamustine for relapsed or refractory indolent B‐cell non‐Hodgkin lymphoma and mantle cell lymphoma

Bendamustine is a unique cytotoxic agent that has demonstrated efficacy in the treatment of indolent B‐cell non‐Hodgkin lymphomas (B‐NHLs). In this multicenter phase II trial, the efficacy and safety of bendamustine were evaluated in Japanese patients with relapsed or refractory indolent B‐NHL or mantle‐cell lymphoma (MCL). Patients received bendamustine (120 mg/m2) on days 1–2 of a 21‐day cycle, for up to six cycles. The primary endpoint was the overall response rate (ORR) as assessed by an extramural committee according to International Workshop Response Criteria (IWRC). Secondary endpoints included complete response (CR) rate, ORR according to Revised Response Criteria (revised RC), progression‐free survival (PFS), and safety. Fifty‐eight patients with indolent B‐NHL and 11 with MCL were enrolled. By IWRC, bendamustine produced an ORR of 91% (95% confidence interval [CI], 82–97%; 90% and 100% in patients with indolent B‐NHL and MCL, respectively), with a CR rate of 67% (95% CI, 54–78%). ORR and CR rates according to revised RC were 93% (95% CI, 84–98%) and 57% (95% CI, 44–68%), respectively. After a median follow‐up of 12.6 months, median PFS had not been reached. Estimated PFS rates at 1 year were 70% and 90% among indolent B‐NHL and MCL patients, respectively. Bendamustine was generally well tolerated. Reversible myelosuppression, including grade 3/4 leukopenia (65%) and neutropenia (72%), was the most clinically significant toxicity observed. Common non‐hematologic toxicities included mild gastrointestinal events and fatigue. These results demonstrate the high efficacy and tolerability of single‐agent bendamustine in relapsed patients with indolent B‐NHL or MCL histologies. (ClinicalTrials.gov ID: NCT00612183). (Cancer Sci 2010;)

Expression of a tumor-associated antigen RCAS1 in hepatocellular carcinoma.

RCAS1 has been reported as a tumor-associated antigen in uterine and ovarian carcinomas. In vitro studies on RCAS1 indicated that it might function as an apoptosis-inducing factor since binding between RCAS1 and its receptor induced apoptosis in receptor-expressing cells. In this study, 68 surgically resected samples of hepatocellular carcinoma (HCC) were prepared and RCAS1 expression was examined immunohistochemically, because RCAS1 was also positive in all HCC cell lines tested. Clinical and pathological parameters were then compared between RCAS1-positive and -negative HCC cases. As a result, RCAS1 is expressed in 26.5% of HCC cases and vascular invasion is observed at a much higher rate in the RCAS1-positive cases (72.2%) than in RCAS1-negative cases (24.0%). RCAS1 is not an antigen specific for gynecological cancers. In HCC cases, the RCAS1-positive percentage is not high, however, RCAS1-positive HCCs exhibited a trend towards invasive character.

Monitoring of Hepatitis B Virus (HBV) DNA and Risk of HBV Reactivation in B-Cell Lymphoma: A Prospective Observational Study

BACKGROUND There is no standard management of reactivation of hepatitis B virus (HBV) infection in HBV-resolved patients without hepatitis B surface antigen (HBsAg), but with antibodies against hepatitis B core antigen and/or antibodies against HBsAg (anti-HBs). METHODS We conducted a prospective observational study to evaluate the occurrence of HBV reactivation by serial monthly monitoring of HBV DNA and to establish preemptive therapy guided by this monitoring in B-cell non-Hodgkin lymphoma (B-NHL) treated with rituximab plus corticosteroid-containing chemotherapy (R-steroid-chemo). The primary endpoint was the incidence of HBV reactivation defined as quantifiable HBV DNA levels of ≥ 11 IU/mL. RESULTS With a median HBV DNA follow-up of 562 days, HBV reactivation was observed in 21 of the 269 analyzed patients. The incidence of HBV reactivation at 1.5 years was 8.3% (95% confidence interval, 5.5-12.4). No hepatitis due to HBV reactivation was observed in patients who received antiviral treatment when HBV DNA levels were between 11 and 432 IU/mL. An anti-HBs titer of <10 mIU/mL and detectable HBV DNA remaining below the level of quantification at baseline were independent risk factors for HBV reactivation (hazard ratio, 20.6 and 56.2, respectively; P < .001). Even in 6 patients with a rapid increase of HBV due to mutations, the monthly HBV DNA monitoring was effective at preventing HBV-related hepatitis. CONCLUSIONS Monthly monitoring of HBV DNA is useful for preventing HBV reactivation-related hepatitis among B-NHL patients with resolved HBV infection following R-steroid-chemo (UMIN000001299).

Long-term outcomes after hematopoietic SCT for adult T-cell leukemia/lymphoma: results of prospective trials

We have previously conducted clinical trials of allogeneic hematopoietic SCT with reduced-intensity conditioning regimen (RIC) for adult T-cell leukemia/lymphoma (ATLL)—a disease caused by human T-lymphotropic virus type 1 (HTLV-1) infection and having a dismal prognosis. Long-term follow-up studies of these trials revealed that 10 of the 29 patients have survived for a median of 82 months (range, 54–100 months) after RIC, indicating a possible curability of the disease by RIC. However, we have also observed that the patterns of post-RIC changes in HTLV-1 proviral load over time among the 10 survivors were classified into three patterns. This is the first report to clarify the long-term outcomes after RIC for ATLL patients.

Allogeneic Hematopoietic Stem Cell Transplantation Using Reduced-Intensity Conditioning for Adult T Cell Leukemia/Lymphoma: Impact of Antithymocyte Globulin on Clinical Outcome

Allogeneic hematopoietic stem cell transplantation (HSCT) is an effective treatment for adult T cell leukemia/lymphoma (ATLL), but shows high mortality. We evaluated the feasibility of reduced-intensity transplantation using fludarabine and busulfan, with particular focus on the clinical impact of antithymocyte globulin (ATG) in the conditioning regimen. Fourteen elderly patients with aggressive ATLL were enrolled in the current study without ATG, and were compared to those in 15 patients who were treated similarly, but with ATG, in our previous study. Engraftment was prompt, and treatment was tolerable. Overall (OS) and progression-free survival (PFS) at 3 years were 36% and 31%, respectively. HTVL-1 proviral load became undetectable by the polymerase chain reaction in 62% of patients. Compared to the previous study with ATG, complete donor chimera was significantly delayed. Although early relapse tended to be decreased, OS or PFS was not improved significantly. Analysis of combined data from both our current and previous studies disclosed that grade I-II acute GVHD was the only factor that favorably affected OS and PFS. These data suggested the presence of a graft-versus-ATLL effect and the feasibility of a transplant procedure without ATG in elderly ATLL patients, but could not demonstrate the clinical benefit of incorporating ATG.

Pretransplantation anti-CCR4 antibody mogamulizumab against adult T-cell leukemia/lymphoma is associated with significantly increased risks of severe and corticosteroid-refractory graft-versus-host disease, nonrelapse mortality, and overall mortality

PURPOSE Allogeneic hematopoietic stem-cell transplantation (allo-HSCT) is one important treatment option for patients with aggressive adult T-cell leukemia/lymphoma (ATLL). Mogamulizumab (anti-CCR4 monoclonal antibody; Mog) was recently approved as a treatment for ATLL in Japan. Major concerns exist about the possible adverse effects of pretransplantation Mog because Mog depletes regulatory T cells for several months. We assessed the impact of pretransplantation Mog on clinical outcomes after allo-HSCT. PATIENTS AND METHODS We included 996 allo-HSCT recipients age 70 years or younger with aggressive ATLL who were given the diagnosis between 2000 and 2013 and who received intensive chemotherapy by multiple chemotherapeutic drugs as first-line therapy. Before allo-HSCT, 82 patients received Mog with a median interval of 45 days from the last Mog to allo-HSCT. RESULTS Pretransplantation Mog was associated with an increased risk of grade 3 to 4 acute graft-versus-host disease (GVHD; relative risk, 1.80; P < .01) and refractoriness to systemic corticosteroid for acute GVHD (relative risk, 2.09; P < .01). One-year cumulative incidence of nonrelapse mortality was significantly higher in patients with pretransplantation Mog compared with those without (43.7% v 25.1%; P < .01). The probability of 1-year overall survival was also significantly inferior in patients with pretransplantation Mog compared with those without (32.3% v 49.4%; P < .01). In particular, use of Mog with intervals < 50 days to allo-HSCT was associated with a dismal clinical outcome. CONCLUSION Pretransplantation Mog was significantly associated with an increased risk of GVHD-related mortality, which supports the relevance of CCR4-expressing Tregs after allo-HSCT in humans. In clinical practice, Mog should be cautiously used for patients with ATLL who are eligible for allo-HSCT.

Recent advances in the treatment of adult T‐cell leukemia‐lymphomas

Recent advances in treatment for adult T‐cell leukemia‐lymphoma (ATL) are reviewed herein. It is currently possible to select a therapeutic strategy for ATL and predict prognosis by classification of patients by clinical subtypes and clinicopathological factors. Although the overall survival (OS) of patients with ATL has increased marginally because of advances in chemotherapy, further prolongation of survival might be difficult with conventional chemotherapy alone. Promising results have been reported for antiviral therapy using zidovudine and interferon‐α, and, indeed, antiviral therapy is currently the standard treatment for patients with ATL in western countries. Remarkably, the 5‐year OS rates are 100% for both the smoldering‐type and chronic‐type ATL. Recently, treatments for ATL have included allogeneic hematopoietic stem cell transplantation and molecular targeted therapies. Furthermore, the anti‐CCR4 monoclonal antibody mogamulizumab has been shown to have marked cytotoxic effects on ATL cells, especially in the leukemic type of ATL. In the lymphoma type of ATL, the response rate may be improved by combining mogamulizumab with chemotherapy. It should be recognized that prevention of infection from carriers of human T‐cell leukemia virus type‐I and transfer of the virus from mother to infant are crucial issues for the eradication of ATL.

The tumor-associated antigen, RCAS1, can be expressed in immune-mediated diseases as well as in carcinomas of biliary tract

BACKGROUND/AIMS RCAS1, which is recognized by the specific antibody 22-1-1, was first identified as a tumor-associated antigen in gynecological carcinomas. RCAS1 is the ligand of a putative receptor present on lymphocytes, the expression of which is enhanced by lymphocyte activation. RCAS1 inhibits the growth of receptor-bearing cells and induces apoptotic death. Here we examined RCAS1 expression in biliary diseases. METHODS RCAS1 expression was immunohistochemically examined on tissue samples. Apoptotic death was analyzed by DNA fragmentation detection method. RCAS1 production by cell lines was investigated by flow cytometry, enzyme-linked immunosorbent assay, and reverse transcription-polymerase chain reaction. RESULTS All cholangiocarcinoma cell lines examined clearly expressed RCAS1 at both the protein and RNA level. Immunohistochemically, RCAS1 was expressed in a high percentage of biliary adenocarcinomas (85.9% of intrahepatic cholangiocarcinomas, 96.4% of extrahepatic cholangiocarcinomas and gallbladder carcinomas). Apoptotic tumor-infiltrating lymphocytes could be found in these specimens. RCAS1 expression was frequently detected also in biliary epithelial cells in cases of immune-mediated cholangitis (74.2% in primary biliary cirrhosis, 66.6% in graft-versus-host disease), although the staining pattern for RCAS1 was different compared with cancer cells. CONCLUSIONS RCAS1 is highly expressed not only in cancer cells but also in non-tumor bile duct cells subjected to immune attack.

Clinical outcomes of a novel therapeutic vaccine with Tax peptide-pulsed dendritic cells for adult T cell leukaemia/lymphoma in a pilot study

Adult T cell leukaemia/lymphoma (ATL) is a human T cell leukaemia virus type‐I (HTLV‐I)‐infected T cell malignancy with poor prognosis. We herein developed a novel therapeutic vaccine designed to augment an HTLV‐I Tax‐specific cytotoxic T lymphocyte (CTL) response that has been implicated in anti‐ATL effects, and conducted a pilot study to investigate its safety and efficacy. Three previously treated ATL patients, classified as intermediate‐ to high‐risk, were subcutaneously administered with the vaccine, consisting of autologous dendritic cells (DCs) pulsed with Tax peptides corresponding to the CTL epitopes. In all patients, the performance status improved after vaccination without severe adverse events, and Tax‐specific CTL responses were observed with peaks at 16–20 weeks. Two patients achieved partial remission in the first 8 weeks, one of whom later achieved complete remission, maintaining their remission status without any additional chemotherapy 24 and 19 months after vaccination, respectively. The third patient, whose tumour cells lacked the ability to express Tax at biopsy, obtained stable disease in the first 8 weeks and later developed slowly progressive disease although additional therapy was not required for 14 months. The clinical outcomes of this pilot study indicate that the Tax peptide‐pulsed DC vaccine is a safe and promising immunotherapy for ATL.