Refractory Adult T-cell Leukemia-lymphoma Research Articles

Clinical activity of 9-ING-41, a small molecule selective glycogen synthase kinase-3 beta (GSK-3β) inhibitor, in refractory adult T-Cell leukemia/lymphoma

ABSTRACT GSK-3β is a serine/threonine kinase implicated in tumorigenesis and chemotherapy resistance. GSK-3β blockade downregulates the NF-κB pathway, modulates immune cell PD-1 and tumor cell PD-L1 expression, and increases CD8 + T cell and NK cell function. We report a case of adult T-cell leukemia/lymphoma (ATLL) treated with 9-ING-41, a selective GSK-3β inhibitor in clinical development, who achieved a durable response. A 43-year-old male developed diffuse lymphadenopathy, and biopsy of axillary lymph node showed acute-type ATLL. Peripheral blood flow cytometry revealed a circulating clonal T cell population, and CSF was positive for ATLL involvement. After disease progression on the 3rd line of treatment, he started treatment with 9-ING-41 monotherapy in a clinical trial (NCT03678883). CT imaging after seven months showed a partial response. Sustained reduction of peripheral blood ATLL cells lasted 15 months. Treatment of patient-derived CD8 + T cells with 9-ING-41 increased the secretion of IFN-γ, granzyme B, and tumor necrosis factor-related apoptosis-inducing ligand (TRAIL). In conclusion, treatment of a patient with refractory ATLL with the GSK-3β inhibitor 9-ING-41 resulted in a prolonged response. Ongoing experiments are investigating the hypothesis that 9-ING-41-induced T cell activation and immunomodulation contributes to its clinical activity. Further clinical investigation of 9-ING-41 for treatment of ATLL is warranted.

Safety and effectiveness of mogamulizumab in relapsed or refractory adult T-cell leukemia-lymphoma.

ObjectiveThis prospective, observational, postmarketing surveillance was conducted to evaluate the safety and effectiveness of mogamulizumab, an anti‐CC chemokine receptor 4 (CCR4) monoclonal antibody, in patients with CCR4‐positive, relapsed or refractory (r/r) adult T‐cell leukemia‐lymphoma (ATL) in Japan.MethodAll patients were scheduled to receive intravenous infusions of mogamulizumab 1.0 mg/kg once weekly for 8 weeks, alone or in combination with other modalities.ResultsIn the safety analysis population comprising 572 patients, mogamulizumab therapy was started between May 29, 2012, and April 30, 2013, and adverse drug reactions (ADRs) were reported in 73.4% (38.6% serious cases) of patients. The most common ADRs were skin disorders (33.2% [10.8% serious cases]), infusion‐related reactions (30.1% [4.7% serious cases]), and infections (22.0% [14.7% serious cases]). In the effectiveness analysis population comprising 523 patients, the best overall response rate and the response rate at the end of therapy were 57.9% and 42.0%, respectively. The median overall survival was 5.5 months. Safety and effectiveness results were similar between patients aged ≥70 and <70 years.ConclusionThis postmarketing surveillance confirmed the safety and effectiveness of mogamulizumab for the treatment of patients with r/r ATL, including elderly patients, in clinical practice.

Impact of pretransplant anti-CCR4 antibody administration on clinical outcomes in allogeneic hematopoietic stem cell transplantation

Adult T-cell leukemia-lymphoma (ATL) is a peripheral T-cell lymphoma caused by human T-cell lymphotropic virus type I. Patients with aggressive ATL exhibit poor outcomes, even with dose-dense intensive chemotherapy. Thus, allogeneic hematopoietic stem cell transplantation (allo-HSCT) is considered in all patients eligible for transplant. However, patients with aggressive ATL often have chemo-refractoriness or experience early relapse during chemotherapy. Allo-HSCT is often ineffective in patients with active disease status. Mogamulizumab (Moga) was approved in 2012 in Japan as a potent treatment option for patients with relapsed or refractory ATL. However, there is a major concern that the use of Moga before allo-HSCT could increase the risk of post-transplant complications, such as graft-versus-host disease (GVHD), because Moga depletes regulatory T cells. Here, we would like to describe the possible effects of pre-transplant Moga on post-transplant complications, such as acute GVHD, and to discuss how Moga could be efficiently incorporated in the treatment regimen of patients with aggressive ATL to maximize the expected clinical benefit.

Role of anti-CCR4 antibody in the treatment of transplant-eligible patients with aggressive adult T-cell leukemia/lymphoma

Adult T-cell leukemia/lymphoma (ATL) is a peripheral T-cell lymphoma caused by the human T-cell lymphotropic virus type I. Patients with aggressive ATL show dismal prognoses, even with intensive dose-dense chemotherapy. Such patients often show chemo-refractoriness. Mogamulizumab (Moga) is a potent treatment option for patients with relapsed or refractory ATL. However, use of Moga before allo-HSCT could theoretically increase the risk of post-transplant complications like graft-versus-host disease (GVHD) as Moga depletes regulatory T-cells (Tregs). We retrospectively assessed the impact of Moga on post-transplant outcomes using data from a nationwide survey. Pre-transplant administration of Moga was associated with an increased risk of grade 3 to 4 acute GVHD and refractoriness to systemic corticosteroid for acute GVHD. The one-year cumulative incidence of non-relapse mortality was significantly higher in patients who were treated with Moga pre-transplant compared with those who were not (43.7% vs. 25.1%, P<0.01). The probability of one-year overall survival was also significantly lower in patients with pre-transplant Moga use compared to those without (32.3% vs. 49.4%, P<0.01). In summary, pre-transplant Moga was significantly associated with an increased risk of GVHD-related mortality, which supports the relevance of CCR4-expressing Tregs after allo-HSCT in humans.

Mogamulizumab for the treatment of relapsed or refractory adult T-cell leukemia-lymphoma

ABSTRACTIntroduction: Adult T-cell leukemia-lymphoma (ATL) is an aggressive variant of peripheral T-cell lymphoma of CD4+ T-malignant cells caused by human T-lymphotropic virus type-1. Despite aggressive treatment with multidrug combination chemotherapies, ATL confers a poor prognosis and commonly develops resistance to conventional treatments.Areas covered: Mogamulizumab is a humanized, defucosylated monoclonal antibody that acts by targeting the CC chemokine receptor 4 (CCR4) on malignant cells of ATL. In phase I and II clinical trials, it has achieved overall response rates of 31–50% in CCR4+ malignancies. The most commonly observed hematologic and non-hematologic adverse events included lymphocytopenia, neutropenia, leukocytopenia, infusion reaction, rash, and pyrexia.Expert commentary: Mogamulizumab has shown significant efficacy in treating ATL with moderately high response rates and has been approved in Japan for use in ATL. It may serve as a bridge therapy to achieve disease control prior to allogeneic hematopoietic stem cell transplantation. It also offers potential for use in combination with conventional chemotherapy. Determining the optimal combination of mogamulizumab with conventional and novel therapies remains an important strategy to improve the prognosis of patients with ATL.

SAFETY AND EFFICACY OF MOGAMULIZUMAB IN PATIENTS WITH ADULT T‐CELL LEUKEMIA‐LYMPHOMA IN JAPAN: INTERIM RESULTS OF POSTMARKETING ALL‐CASE SURVEILLANCE

We present the interim results of a postmarketing all-case surveillance study in patients with C–C chemokine receptor 4 (CCR4)-positive, relapsed or refractory adult T-cell leukemia–lymphoma (ATL) treated with the anti-CCR4 monoclonal antibody mogamulizumab since its 2012 launch in Japan. The safety and efficacy analysis populations comprised 484 and 442 patients, respectively. The ATL subtype was acute in 58.9% and lymphoma in 34.2% of patients. All patients were scheduled to receive intravenous infusions of mogamulizumab (1.0 mg/kg) once weekly for eight weeks, alone or in combination with other modalities. Adverse drug reactions (ADRs) were reported in 74.0% of patients, of which 35.7% were serious and 6.2% were fatal. The priority survey items of infusion-related reaction, skin disorder, infection, immune disorder, and tumor lysis syndrome were reported in 29.3, 34.3, 22.1, 3.5, and 2.5% of patients, respectively. Graft-versus-host disease was reported in 25/42 patients who received mogamulizumab before allogeneic hematopoietic stem cell transplantation. The best overall response rate was 57.7% overall, 57.5% in patients treated with mogamulizumab alone, and 58.2% in patients treated with combination therapy. This surveillance indicates that mogamulizumab shows acceptable tolerability in practice; however, because of the risk of serious/fatal ADRs, patients administered mogamulizumab should be carefully monitored.

The Impact of a Humanized CCR4 Antibody (Mogamulizumab) on Patients with Aggressive-Type Adult T-Cell Leukemia-Lymphoma Treated with Allogeneic Hematopoietic Stem Cell Transplantation.

Although a humanized CCR4 antibody (mogamulizumab) was reported to be effective for refractory adult T-cell leukemia-lymphoma (ATL), several reports regarding the use of mogamulizumab before allo-hematopoietic stem cell transplantation (HSCT) strongly indicated a high incidence of severe acute graft-versus-host-disease (GVHD) and treatment-related mortality (TRM). We retrospectively analyzed nine aggressive-type ATL patients who underwent allo-HSCT at a single institution in Miyazaki from 2006.1.1 to 2015.7.31. Among nine ATL patients, three had used mogamulizumab before treatment with allo-HSCT because of the poor control of refractory ATL. All three patients were treated with four to eight cycles of mogamulizumab. The interval from last administration of mogamulizumab to allo-HSCT was two to five months. All three patients with prior mogamulizumab treatment developed mild-moderate acute GVHD (grade 2) 28, 34, or 40 days after allo-HSCT. Acute GVHD was controlled by prednisolone treatment. Two patients in complete remission before allo-HSCT exhibited relatively prolonged survival (survival rate, 66%). Moreover, one patient developed human T-cell leukemia virus type 1-associated myelopathy-mimicking myelitis at five months after allo-HSCT. In contrast, two of six ATL patients without a history of mogamulizumab use survived (survival rate 33%). Thus, in cases of mogamulizumab use before treatment with allo-HSCT for refractory ATL, an appropriately long interval from the last administration of mogamulizumab to allo-HSCT may be one of factors to reduce TRM by acute GVHD, and to subsequently enhance graft-versus-tumor effects in ATL cases. Furthermore, caution is needed when administering mogamulizumab before allo-HSCT for severe GVHD and TRM.

Clinical Impact of a Humanized CCR4 Antibody (Mogamulizumab) in 14 Patients with Aggressive Adult T-cell Leukemia-lymphoma Treated at a Single Institution During a Three-year Period (2012-2014).

Objective We elucidated the effectiveness of a humanized CCR4 antibody (mogamulizumab) on adult T-cell leukemia-lymphoma (ATL), which typically has a poor outcome. Methods We retrospectively analyzed 14 patients with aggressive ATL who had been treated at our institution with weekly cycles of mogamulizumab for eight weeks from 2012-2014. Results The patients (median age: 63 years old) were classified as having acute- (n=10) or lymphoma-type (n=4) ATL. The prior treatment regimens consisted of CHOP, VCAP-AMP-VECP, DeVIC and CHASE, with an average of two courses (range: 1-4). The prior disease responses were partial remission (n=3) and progressive disease (n=11). The treatment was administered in the primary refractory setting (n=8), for relapse (n=2), or as bridging therapy before hematopoietic stem cell transplantation (n=4). The overall response rates were 64% and 43% after four and eight cycles (or after the final cycles), respectively. The median overall survival (OS), OS rate at six months and OS rate at 12 months were 66 days, 41.7% and 20.8%, respectively. All of the patients with acute-type ATL who showed a response to treatment had an early response. Notably, six of the 14 ATL patients showed somewhat prolonged survival (>100 days). However, relapse or disease progression in the peripheral blood, central nervous system, lymph nodes, skin, and/or bone occurred within a relatively short period after treatment. The adverse effects were tolerable, and included lymphopenia, cytomegalovirus infection and skin rash. Conclusion Mogamulizumab therapy resulted in an early and high remission rate and somewhat prolonged survival in patients with refractory ATL. However, the duration of remission was short, and there was early relapse and disease progression. This study may show the current impact of mogamulizumab in clinical practice.

Mogamulizumab Therapy for Adult T-Cell Leukemia-Lymphoma: A Retrospective Multicenter Study

Introduction: Adult T-cell leukemia-lymphoma (ATL) is a peripheral T-cell malignancy, which is caused by human T-cell leukemia virus type I (HTLV-1) and is considered to be derived from regulatory T cells (Treg). ATL is usually resistant to conventional chemotherapies and the patients with ATL have very poor prognosis. Mogamulizumab (Moga) is a humanized monoclonal antibody against CC chemokine receptor 4 (CCR4) which is expressed on T-helper type 2, Treg and tumor cells from most patients with ATL. It was reported that Moga used to treat ATL with 50% efficacy in a phase II study and frequently developed cutaneous adverse reactions (CAR). In that study, development of CAR was reported to be closely associated with the response to Moga therapy. To confirm efficacy and safety of Moga therapy for ATL, we retrospectively analyzed relapsed or refractory ATL patients who were treated by Moga at 4 institutes in Kagoshima, one of the endemic areas of HTLV-1 infection, Southwestern Japan.Patients and methods: There were 77 patients, who were received Moga therapy between March, 2007 (phase I study) and December, 2014. We studied about backgrounds (age, sex, subtypes of ATL, ECOG performance status (PS) at diagnosis and clinical stage) of the patients, contents of prior therapy and the response, prognostic index for acute and lymphoma type ATL (ATL-PI), PS and disease status at Moga therapy, response and adverse events (AE) of Moga therapy, and the survival.Results: Enrolled patients were 44 men and 33 women, and median age at Moga therapy was 65.6 years (range: 44-83 years). They consisted 54 acute, 18 lymphoma, and 5 chronic type ATL, and ATL-PI was low in 18, intermediate in 43 and high in 16 patients. Initial induction chemotherapies were mainly VCAP-AMP-VECP regimen in 41, CHOP like regimen in 19 patients. Median duration between diagnosis and Moga therapy was 8.1 months (range: 0.5-94.9 months). They were administered Moga median 5 cycles (range: 1-10 cycles). Disease status at Moga therapy were 23 relapsed and 54 refractory [partial response (PR): 8, stable disease (SD): 15, progressive disease (PD): 31] disease. Myelosuppression associated with Moga, development of cytomegalovirus antigenemia (19.5%) and other AE were tolerable. Best objective response rate was 42.9% including 18 complete remission (CR) and 15 PR. Fifty-four patients died after Moga therapy (50 from ATL, 4 from infection and so on). Median overall survival (OS) time from Moga therapy was 7.7 months (95%CI: 5.1-11.2 months) and 3-year OS rate was 18.2%. The cohort included 27 patients over 70 years, but their survival was no worse than younger. Twelve patients received allogeneic hematopoietic stem cell transplantation after Moga therapy, but had no survival advantage. Twenty-four patients suffered from CAR, which were developed median 7 cycles (range: 2-8 cycles). The severity of CAR according to CTCAE v3.0 was grade 1 in three, 2 in eight, 3 in eleven and 4 in two patients, respectively. In patients (n = 51) received Moga more than 4 cycles, 22 patients suffered from CAR and their OS (3-year OS: 43.6%) was significantly better than patients without CAR (median OS: 23.4 vs 7.9 months, p = 0.0003).Discussion: Moga therapy is effective and safe for ATL patients and the onset of moderate CAR is a favorable sign of the efficacy. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Anti-CCR4 monoclonal antibody KW-0761 (mogamulizumab) or investigator's choice in subjects with relapsed or refractory adult T-cell leukemia-lymphoma (ATL)

The receptor for macrophage derived chemokine (MDC) and thymus- and activation-regulated chemokine (TARC) CC chemokine receptor 4 (CCR4) is over expressed in several T-cell malignancies including HTLV-1 related ATL where approximately 90% of malignant cells have been shown to over express this chemokine receptor. The HTLV-1 transactivator gene (Tax) does not directly induce CCR4 expression. Rather, expression of CCR4 is controlled by the constitutive activation of several transcription factors in HTLV-1 infected cells. Inhibiting the expression of these transcription factors with small-interfering RNAs has been shown to block CCR4 expression and also reduce proliferation of the affected cells. Patients with CCR4 positive ATL are more likely to have skin involvement and shorter overall survival (OS; median 9.5 months) compared with CCR4-negative (20.6 months) patients. Mogamulizumab is a defucosylated, humanized, monoclonal antibody with enhanced antibody-dependent cellular cytotoxicity (Potelligent®) against primary ATL cells that bind to CCR4.

Lenalidomide in patients with Relapsed or Refractory HTLV-1 Related Adult T cell Leukemia/Lymphoma (ATLL)

Adult T-cell Leukemia/Lymphoma (ATLL) is resistant to chemotherapy and the acute and lymphomatous subtypes of disease have a dismal prognosis. There is no standard therapy for relapsed or refractory disease in Western countries and new agents are being explored. Lenalidomide is an immunomodulatory agent with promising activity in hematologic malignancies, including non-Hodgkin's lymphoma and represents a novel therapeutic option. We investigated the safety and efficacy of lenalidomide (25 mg once daily) on Days 1 to 21 of every 28-day cycle in a phase two study of patients with relapsed or refractory ATLL. The study was closed early due to limited patient accrual. Of 4 patients enrolled, no response was observed in two patients evaluable for response. No grade 3 or 4 toxicity was noted. In this small single institution experience, lenalidomide showed no clinical activity and manageable toxicity in two evaluable patients with relapsed or refractory ATLL. This experience highlights the need for collaborative studies of this rare disease and enrolling patients on clinical trials promptly.

Cytotoxic T-Lymphocyte Analysis of Aggressive Types of Adult T-Cell Leukemia/Lymphoma Patients with Complete Remission after Intensive Combination Chemotherapy

Introduction: Adult T-cell leukemia/lymphoma (ATLL) is a peripheral T-cell malignancy caused by human T-lymphotropic virus type I (HTLV-I). Most ATLL cells are CD4 and CCR4 positive, and CD8 negative. ATLL is classified into 4 clinical subtypes: smoldering, chronic, acute, and lymphoma. Acute and lymphoma type ATLLs, which are aggressive types, have a very poor prognosis. In Japan, aggressive ATLLs are commonly treated by intensive chemotherapies, such as VCAP-AMP-VECP, modified LSG15 therapy, and biweekly CHOP therapy. Recently, an anti-CCR4 monoclonal antibody (mogamulizumab) was approved for relapse and refractory ATLL in Japan. Mogamulizumab induces a highly potent antibody dependent cellular cytotoxicity, suggesting the importance of immuno-cell therapy for treatment of ATLL. We report here the extremely interesting results of aggressive ATLL patients with long-term survival and complete remission (CR) after activation of cellular immunity against ATLL cells following intensive chemotherapies.Patients and Methods: We retrospectively evaluated 46 cases of aggressive ATLLs diagnosed at the Nagasaki Genbaku Hospital between January 2001 and August 2011. Of these, 7 patients had long-term survival greater than 3 years with CR after intensive chemotherapies. Four of these 7 patients had human leukocyte antigen (HLA)-A02:01 or HLA-A24:02, and were investigated using anti-HTLV-I specific cytotoxic T-lymphocyte (CTL) analysis. The HTLV-I provirus load in peripheral blood was also analyzed.Results: Table 1 summarizes the characteristics of 7 aggressive type ATLL patients with long-term survival. Four patients were male and 3 were female. Six patients were classified as lymphoma type and 1 as acute type ATLL. The median age was 68 (range, 60–78) years. The median survival period from the onset of the disease was 111 (range, 36–165) months. In all 7 patients, the CD4/CD8 ratio reversed during, or shortly after, chemotherapy and CD8 predominance continued for more than 1 year (range, 13–165 months, median 24 months). Three patients had herpes virus infection during chemotherapy and reversal of the CD4/CD8 ratio appeared just after herpes virus infection in 2 of these patients. These observations suggested that HTLV-I specific CTLs were induced and contributed to the treatment of ATLL in these patients. An HTLV-I specific CTL analysis currently is available in patients with HLA-A02:01 and HLA-A24:02. Three of 7 aggressive ATLL patients with long-term survival and CR had HLA-A02:01 and 1 had HLA-A24:02. Therefore, HTLV-I specific CTL analysis and HTLV-I provirus load in the peripheral blood were performed in all 4 patients. Each patient was examined twice, once in 2012 and once in 2014. HTLV-I specific CTLs were detected in all patients (Table 2 and Figure 1). Although all patients maintained CR for, HTLV-I proviruses were detected in the peripheral blood in all patients (Table 2). This phenomenon was observed both in 2012 and in 2014 (Table 2 and Figure 1).Conclusions: The findings from this study suggest that HTLV-I specific CTLs can be induced in patients with aggressive types of ATLL. In patients having long survival with CR, these CTLs can contribute to treatment and may play a roll inhibiting the relapse of ATLL. The development of efficacious methods to induce HTLV-I specific CTLs in individual ATLL patients may lead to improved outcomes for aggressive types of ATLL.Table 1Summary of aggressive type ATLL patients with long-term survival and complete remissionPatientNo.GenderAge(year)Survival fromthe onset of ATLL (months)Duration ofCD4/CD8 reversal(months)Herpes virus infection1Male69165165+2Male6814096+3Female717165-4Male6012413+5Female6111118-6Male783613-7Female655624-Table 2A Summary of HTLV-I specific CTL analysis and HTLV-I provirus load in the peripheral bloodPatient No.HLA20122014CTLHTLV-I provirusCTLHTLV-I provirus(%)(copies/1000 cells)(%)(copies/1000 cells)1A02:010.1135.40.1361.92A02:010.7824.41.5614.75A02:011.067.11.3113.37A24:022.0726.43.6427.9 [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Mogamulizumab for the treatment of adult T-cell leukemia/lymphoma

Mogamulizumab for the treatment of adult T-cell leukemia/lymphoma Makoto Yoshimitsu, Naomichi Arima Division of Hematology and Immunology, Center for Chronic Viral Diseases, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan Abstract: Adult T-cell leukemia/lymphoma (ATLL) is a peripheral T-cell lymphoma caused by latent infection of human T-cell lymphotropic virus type 1. The outcome for ATLL is very poor, with a 3-year overall survival of approximately 24% with conventional chemotherapy; thus, there is an unmet need for developing new treatment options. Defucosylated humanized anti-CC chemokine receptor 4 (CCR4) antibody (KW-0761, mogamulizumab) has been clinically available for the treatment of relapsed or refractory ATLL in Japan since 2012, and a Phase II study of mogamulizumab for patients with relapsed CCR4+ ATLL demonstrated a 50% objective response, a 30.8% complete response, and an acceptable safety profile. Allogeneic hematopoietic stem cell transplantation has been used to treat patients with ATLL, and mogamulizumab in combination with allogeneic hematopoietic stem cell transplantation has been used successfully in a limited number of patients to treat refractory or relapsed ATLL. The efficacy of combining mogamulizumab with standard chemotherapy (mLSG15) for patients with ATLL has also been examined, and the results have shown higher rates of complete response with the combined therapy (52%) compared with for chemotherapy alone (33%). Mogamulizumab also has potential application in the treatment of human T-cell lymphotropic virus type 1-associated myelopathy/tropical paraparesis, Epstein&ndash;Barr virus-associated T-cell and natural killer-cell lymphoproliferative diseases, and peripheral and cutaneous T-cell lymphomas. Possible adverse events of mogamulizumab have been reported, such as cutaneous adverse reactions (including Stevens&ndash;Johnson syndrome), diffuse panbronchiolitis, reactivation of hepatitis B, and opportunistic infections. The treatment outcome of patients with ATLL might be improved by further optimizing the use of mogamulizumab and managing severe adverse events. In this review, we provide an overview of the current treatment options for patients with ATLL and a focused review on the use, application, and adverse events associated with mogamulizumab. Keywords: ATLL, anti-CCR4 antibody, defucosylated antibody, cutaneous adverse reaction

Anti-CCR4 monoclonal antibody KW-0761 (mogamulizumab) or investigator’s choice of chemotherapy in subjects with relapsed or refractory adult T-cell leukemia-lymphoma (ATL).

TPS8622 Background: The receptor for macrophage derived chemokine (MDC) and thymus- and activation-regulated chemokine (TARC) CC chemokine receptor 4 (CCR4) is over expressed in several T-cell mali...

Diffuse panbronchiolitis after humanized anti-CCR4 monoclonal antibody therapy for relapsed adult T-cell leukemia/lymphoma

We present the case of a 62-year-old Japanese woman with relapsed adult T-cell leukemia/lymphoma (ATLL) who was treated with humanized anti-CCR4 monoclonal antibody (KW-0761). Although this antibody was highly effective against refractory ATLL, 6 months after the final KW-0761 infusion, the patient complained of hypoxia due to diffuse panbronchiolitis. Physicians should remain vigilant to the possibility of such previously unreported late-onset adverse effects associated with KW-0761 therapy.

Phase I Study of KW-0761, a Humanized Anti-CCR4 Antibody, in Patients (Pts) with Relapsed or Refractory Adult T-Cell Leukemia-Lymphoma (ATLL) and Peripheral T-Cell Lymphoma (PTCL): Preliminary Results.

Introduction: KW-0761 is a defucosylated humanized IgG1 monoclonal antibody against CC chemokine receptor 4 (CCR4). Previous studies revealed that CCR4 was over-expressed on tumor cells from 88% of pts with ATLL and 38% of pts with PTCL. CCR4 expression was associated with unfavorable prognosis in both diseases. These evidences suggest that CCR4 could be a reasonable molecular target for treatment of CCR4-positive ATLL and PTCL. KW-0761 exerted very potent ADCC but not CDC against cultured ATLL cell lines using normal effecter cells. KW-0761 also exhibited potent ADCC against freshly isolated ATLL cells using the auto-effecter cells.Methods: KW-0761 is being investigated in a Phase I, single-agent, dose-escalation, multicenter study for relapsed or refractory pts with ATLL or PTCL after undergoing the initial chemotherapy. Eligible pts were required to express CCR4 on their tumor cells by FCM and/or IHC. This phase I trial was designed to evaluate toxicity, pharmacokinetics (PK), immunogenicity and anti-tumor activity. Toxicity was evaluated by NCI CTCAE (v3.0). Pts were planned to receive four weekly intravenous injections of KW-0761 at the doses of 0.01, 0.1, 0.5 and 1.0 mg/kg.Results: As of August 10, 2007, 6 pts (1 PTCL and 5 ATLL) have been treated with KW-0761 at the dose of 0.01 (N=3) and 0.1 mg/kg (N=3). Three pts were evaluable for toxicity, PK, immunogenicity and 4 pts were evaluable for anti-tumor activity. KW-0761 was well tolerated with no dose-limiting toxicities. Reversible grade (G) 3 toxicities were lymphocytopenia and herpes zoster. G1-2 adverse events were; rash, constipation, nausea, EF decrease, neutropenia, thrombocytopenia, eosinophilia, lymphocytopenia, ALP increase and QT prolongation. In one leukemic ATLL pt with swollen lymph nodes (LNs) treated at 0.01 mg/kg, peripheral ATLL cells disappeared and the LNs were decreased in size, attaining PR. In another leukemic ATLL pt with skin involvement treated at 0.1 mg/kg, peripheral ATLL cells disappeared and the skin achieved PR by Physicians Global Assessment of Clinical Conditions (PGA). One ATLL pt with skin and bone involvement at 0.01 mg/kg showed SD. Preliminary PK analysis at 0.01 mg/kg showed that Cmax and T1/2 after the 4th dosing was 323.7 56.7 ng/ml and 244 117 hrs, respectively. KW-0761 did not exhibit immunogenicity at 0.01 mg/kg.Conclusions: Preliminary phase I data warrant further investigations of KW-0761, a first-in-class humanized anti-CCR4 antibody, against CCR4-positive peripheral T-cell malignancies including ATLL. Patient accrual is ongoing and the updated results will be presented at the meeting.