Clinical trials for malignant lymphoma in Japan

Clinical characteristics of patients with B-cell lymphoma enrolled in clinical trials for aggressive lymphoma in Japan: Japan Clinical Oncology Group - Lymphoma Study Group study - JCOG0108A

The clinical characteristics of B-cell lymphoma (BCL) were studied through the combined analysis of six clinical trials conducted by the Japan Clinical Oncology Group - Lymphoma Study Group (JCOG-LSG) for aggressive lymphoma in the 1990s, before the introduction of rituximab. Through a central pathological review, 829 patients were diagnosed with BCL according to the World Health Organization classification and treated with doxorubicin-containing combination chemotherapies. Of these patients, 642, 104, 30, and 24 patients were diagnosed with diffuse large B-cell lymphoma (DLBCL), follicular lymphoma (FL), mantle cell lymphoma (MCL), and marginal zone lymphoma (MZL), respectively. The overall survival (OS) of FL and MZL patients was higher than that of patients with DLBCL and MCL. The OS of the MCL patients was higher than that of DLBCL patients in the first 5 years, but MCL had the lowest survival after 5 years. The OS of DLBCL patients was clearly stratified by the international prognostic index and showed data compatible with that of aggressive lymphoma in the pre-rituximab era. These results established the clinical aspects of BCL in a large number of patients treated in prospective studies during the pre-rituximab era in Japan.

Antitumor effects with apoptotic death in human promyelocytic leukemia HL-60 cells and suppression of leukemia xenograft tumor growth by irinotecan HCl

Irinotecan HCl (CPT-11) is an anticancer prodrug, but there is no available information addressing CPT-11-inhibited leukemia cells in in vitro and in vivo studies. Therefore, we investigated the cytotoxic effects of CPT-11 in promyelocytic leukemia HL-60 cells and in vivo and tumor growth in a leukemia xenograft model. Effects of CPT-11 on HL-60 cells were determined using flow cytometry, immunofluorescence staining, comet assay, real-time PCR, and Western blotting. CPT-11 demonstrated a dose- and time-dependent inhibition of cell growth, induction of apoptosis, and cell-cycle arrest at G0/G1 phase in HL-60 cells. CPT-11 promoted the release of AIF from mitochondria and its translocation to the nucleus. Bid, Bax, Apaf-1, caspase-9, AIF, Endo G, caspase-12, ATF-6b, Grp78, CDK2, Chk2, and cyclin D were all significantly upregulated and Bcl-2 was down-regulated by CPT-11 in HL-60 cells. Induction of cell-cycle arrest by CPT-11 was associated with changes in expression of key cell-cycle regulators such as CDK2, Chk2, and cyclin D in HL-60 cells. To test whether CPT-11 could augment antitumor activity in vivo, athymic BALB/c(nu/nu) nude mice were inoculated with HL-60 cells, followed by treatment with either CPT-11. The treatments significantly inhibited tumor growth and reduced tumor weight and volume in the HL-60 xenograft mice. The present study demonstrates the schedule-dependent antileukemia effect of CPT-11 using both in vitro and in vivo models. CPT-11 could potentially be a promising agent for the treatment of promyelocytic leukemia and requires further investigation.

Demethylation restores SN38 sensitivity in cells with acquired resistance to SN38 derived from human cervical squamous cancer cells

Using seven monoclonal SN38-resistant subclones established from ME180 human cervical squamous cell carcinoma cells, we examined the demethylation effects of 5-aza-2′-deoxycytidine (5-aza-CdR) on the SN38-sensitivity of the cells as well as the expression of death-associated protein kinase (DAPK) in the SN38-resistant cells. The DAPK expression levels were evaluated among parent ME180 cells, SN38-resistant ME180 cells and cisplatin-resistant ME180 cells by methylation-specific DAPK-PCR, quantitative RT-PCR and western blot analysis. The SN38-resistant cells co-treated with SN38 and 5-aza-CdR strongly exhibited enhanced SN38-sensitivities resembling those found in the parent cells. In the SN38-resistant subclones, no relationships were found between the restored SN38 sensitivity and hypermethylation of the DAPK promoter, DAPK mRNA expression, DAPK protein expression and induction of DAPK protein after 5-aza-CdR treatment, unlike the strong suppression of 5-aza-CdR-induced DAPK protein expression in the cisplatin-resistant subclones. These findings indicate that reversibly methylated molecules, but not DAPK, may regulate SN38 resistance, and that demethylating agents can be strong sensitizing anticancer chemotherapeutic drugs for SN38-resistant cancers.

CP-690,550, a therapeutic agent, inhibits cytokine-mediated Jak3 activation and proliferation of T cells from patients with ATL and HAM/TSP

The retrovirus, human T-cell-lymphotrophic virus-1 (HTLV-I) is the etiologic agent of adult T-cell leukemia (ATL) and the neurological disorder HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP). The HTLV-I-encoded protein tax constitutively activates interleukin-2 (IL-2), IL-9, and IL-15 autocrine/paracrine systems that in turn activate the Jak3 (Janus kinase 3)/STAT5 (signal transducers and activators of transcription 5) pathway, suggesting a therapeutic strategy that involves targeting Jak3. We evaluated the action of the Jak3 inhibitor CP-690,550 on cytokine dependent ex vivo proliferation that is characteristic of peripheral blood mononuclear cells (PBMCs) from select patients with smoldering or chronic subtypes of ATL, or from those with HAM/TSP whose PBMCs are associated with autocrine/paracrine pathways that involve the production of IL-2, IL-9, IL-15, and their receptors. CP-690,550 at 50 nM inhibited the 6-day ex vivo spontaneous proliferation of PBMCs from ATL and HAM/TSP patients by 67.1% and 86.4%, respectively. Furthermore, CP-690,550 inhibited STAT5 phosphorylation in isolated ATL T cells ex vivo. Finally, in an in vivo test of biological activity, CP-690,550 treatment of mice with a CD8 T-cell IL-15-transgenic leukemia that manifests an autocrine IL-15/IL-15Rα pathway prolonged the survival duration of these tumor-bearing mice. These studies support further evaluation of the Jak3 inhibitor CP-690,550 in the treatment of select patients with HTLV-I-associated ATL and HAM/TSP.

Importance of maintaining the relative dose intensity of CHOP-like regimens combined with rituximab in patients with diffuse large B-cell lymphoma

CHOP-like regimen combined with rituximab is a standard chemotherapy for diffuse large B-cell lymphoma (DLBCL). The relative dose intensity (RDI) was proposed as an index of the dose and administration interval of agents. Previous studies reported that the maintenance of the RDI during CHOP therapy improved the treatment results. However, few studies regarding RDI have reviewed patients receiving combination therapy with CHOP and rituximab. We investigated the influence of RDI maintenance, involving combination therapy with rituximab, on therapeutic effects in patients with DLBCL. We retrospectively examined 152 DLBCL patients who were treated with CHOP-like regimen combined with rituximab in whom the RDI could be followed up. Multivariate analysis revealed that international prognosis index (IPI) high intermediate-high (HI-H) (p = 0.005) and RDI of less than 70% (p = 0.007) were independent prognostic factors for low progression free survival. Concerning overall survival, IPI HI-H (p = 0.027) and an RDI of less than 70% (p = 0.002) were involved in an unfavorable prognosis. In addition, age over 60 years (p = 0.003), R-THPCOP (p = 0.034), or the presence of febrile neutropenia (p = 0.004) made RDI maintenance difficult, and prophylactic G-CSF therapy (p = 0.026) was useful for maintaining the RDI. Maintaining the RDI is important even in the era of rituximab-combined chemotherapy for DLBCL.

4. Antibody therapy for malignant lymphoma

Rituximab, a genetically engineered, chimeric anti-CD20 monoclonal antibody, induces the apoptosis of B-lymphoma cells, in addition to the lyses by complement-dependent cytotoxicity (CDC) and antibody-dependent cell-mediated cytotoxicity (ADCC), as shown in Fig. 1. A Japanese phase I study of rituximab in relapsed or refractory patients with B-cell non-Hodgkin's lymphoma (B-NHL) showed an overall response rate (ORR) of 64% (7/11) with minimal toxicities. Elimination half-life (T(1/2)) of serum rituximab was 445+/-361 hours, and the serum rituximab was detectable at three months. In the subsequent phase II study, 90 relapsed or refractory patients with indolent B-NHL or mantle cell lymphoma (MCL) were treated with rituximab at 375 mg/m2x4 weekly infusions. ORRs in indolent B-NHL and MCL were 61% (37/61) and 46% (6/13), respectively. In this presentation, the results of clinical trials of antibody therapy of malignant lymphoma are summarized, focusing on the two recent Japanese multicenter trials of rituximab and a Japanese feasibility study of anti-CD20 radioimmunotherapy with yttrium-90-lableled ibritumomab tiuxetan.

Clinical significance of a blood eosinophilia in adult T-cell leukemia/lymphoma: a blood eosinophilia is a significant unfavorable prognostic factor

We investigated the clinical significance of a blood eosinophilia in a cohort of 158 consecutive patients with adult T-cell leukemia/lymphoma (ATLL), and multivariate analysis revealed that a blood eosinophilia was an independent and a significant unfavorable prognostic factor. Interestingly, a blood eosinophilia was independent of serum LDH level, which might reflect the tumor burden. The present study shows that measurement of the blood eosinophil count is useful for predicting the prognosis and for determining a suitable treatment strategy for ATLL patients.

Clinical significance of serum Th1-, Th2- and regulatory T cells-associated cytokines in adult T-cell leukemia/lymphoma: high interleukin-5 and -10 levels are significant unfavorable prognostic factors

Patients with adult T-cell leukemia/lymphoma (ATLL) are in a severely immunocompromised state. Therefore, it is assumed that ATLL cells either express particular cytokines or induce their expression in host immune cells, disrupting the balanced production of cytokines and causing the host's immune system to break down. We examined the levels of serum cytokines including T helper type 1- (Th1-) associated cytokines [IFN-gamma, TNF-alpha, and interleukin (IL)-2], Th2-associated cytokines (IL-4, -5 and -6) and regulatory T cell-associated cytokines (IL-10 and TGF-beta1) in 94 ATLL patients, 39 asymptomatic human T-cell lymphotropic virus type-1 (HTLV-1) carriers and 50 healthy adult volunteers, to clarify whether elevated levels of particular cytokines are associated with the prognosis of ATLL patients. On multivariate analysis, high IL-5 and IL-10 levels were independent and significant unfavorable prognostic factors among the ATLL patients. The IL-10 level significantly increased with disease progression at each step from asymptomatic HTLV-1 carrier to ATLL of the indolent variant (chronic and smoldering subtypes) to ATLL of the aggressive variant (acute and lymphoma subtypes). Furthermore, high IL-10 was significantly associated with high lactate dehydrogenase (LDH), indicating that the IL-10 level reflects the tumor burden. The IL-5 level was not associated with disease progression nor LDH. Among ATLL patients with the aggressive variant, high IL-5, but not high IL-10, was an independent and significant unfavorable prognostic factor on multivariate analysis. Measurement of serum IL-5 and IL-10 levels is useful for predicting the prognosis and for determining a suitable treatment strategy for ATLL patients.

Case of a patient with progressive adult T-cell leukemia/lymphoma treated successfully by reduced-intensity conditioning stem cell transplantation from an HLA-incompatible related donor

A 61-year-old man with progressive adult T-cell leukemia/lymphoma (ATLL) successfully received reduced-intensity conditioning stem cell transplantation (RIST) without T-cell depletion (TCD) from his HLA-incompatible son, who had negative results for human T-lymphotropic virus type 1 (HTLV-1) (1-locus, 1-allele mismatch in the graft-versus-host [GVH] direction; 2-loci, 1-allele mismatch in the host-versus-graft direction). The preparatory regimen consisted of fludarabine, busulfan, and rabbit antithymocyte globulin. GVH disease (GVHD) prophylaxis consisted of short-term administration of methotrexate, tacrolimus, and methylprednisolone. The patient achieved complete donor chimerism on day 30 after transplantation. On approximately day 50 the patient started to experience steroid-refractory skin GVHD (grade IV), which was successfully managed with basiliximab (anti-CD25 monoclonal antibody) and mycophenolate mofetil (MMF). Serial analysis of HTLV-1 proviral load by quantitative polymerase chain reaction analysis using whole peripheral blood demonstrated undetectable levels from day 90. At the time of this writing the patient had been in complete remission for more than 16 months. The results in this case suggest the potential of non-TCD RIST from an HLA-incompatible relative donor as an alternative source of hematopoietic stem cells even for an elderly patient with advanced ATLL. In addition, basiliximab combined with MMF may be effective for the treatment of steroid-refractory skin GVHD without deteriorating the graft-versus-ATL effect.