Combination therapy with dendritic cell vaccine and IL-2 encapsulating polymeric micelles enhances intra-tumoral accumulation of antigen-specific CTLs.

Dendritic cell (DC) vaccine is a promising immunotherapy for cancer due to its ability to induce antigen-specific CTLs efficiently. However, a number of clinical studies have implied insufficient therapeutic benefits with the use of MHC class 1 restricted peptide-pulsed DC vaccine. To enhance the clinical efficacy, we examined combination therapy of DC vaccine pulsed with OVA peptide and intravenous low dose unmodified IL-2 (IL-2 solution) administration against EG7 tumor-bearing mice. Unexpectedly, no additional effects of IL-2 solution were observed on CTL induction and the therapeutic effects of DC vaccine, possibly because of the short half-life of IL-2 in plasma. Therefore, we generated IL-2-encapsulating polymeric micelles (IL-2 micelle), which showed prolonged IL-2 retention in the circulation after intravenous administration compared with IL-2 solution. When mice were treated with OVA peptide-pulsed DCs in combination with IL-2 micelle, OVA-specific CTLs were efficiently induced in the spleen in comparison with DC vaccine combined with IL-2 solution or DC vaccine alone. In addition, combination therapy of DC vaccine and IL-2 micelle against EG7 tumor-bearing mice induced the efficient accumulation of antigen-specific CTLs into the tumor and marked anti-tumor effects. Thus, the administration of IL-2 micelle can significantly enhance DC vaccine efficacy against tumors.

Effect of combined treatment with the epirubicin-incorporating micelles (NC-6300) and 1,2-diaminocyclohexane platinum (II)-incorporating micelles (NC-4016) on a human gastric cancer model.

Anticancer agent-incorporating polymeric micelles accumulate effectively in tumors via the enhanced permeability and retention effect to exert potent antitumor effects. However, combined use of such micelles has not been elucidated. We compared the effect of combining the epirubicin-incorporating micelle NC-6300 and 1,2-diaminocyclohexane platinum (II) (oxaliplatin parent complex)-incorporating micelle NC-4016 (NCs) with that of epirubicin and oxaliplatin (E/O) in 44As3Luc cells using the combination index method. The in vivo antitumor activities of NCs and E/O were evaluated in mice bearing 44As3Luc xenografts. Pharmacokinetic analysis was performed by high-performance liquid chromatography and mass spectrometry. Cardiotoxicity of NC-6300 and epirubicin was assessed by echocardiography. Neurotoxicity of NC-4016 and oxaliplatin was evaluated by examining the paw withdrawal response to noxious mechanical stimuli. NCs showed a highly synergistic activity equivalent to E/O. In vivo, NCs exhibited higher antitumor activity in the subcutaneous tumor model and longer overall survival in the orthotopic tumor model than E/O (p < 0.001, p = 0.015, respectively). The intratumor concentrations of epirubicin and platinum were significantly higher following NCs than following E/O administration. Moreover, the micelles showed lower cardiotoxicity and neurotoxicity than the corresponding conventional drugs. The combined use of the micelles was associated with remarkable efficacy and favorable toxicities in the human gastric cancer model, and warrants the conduct of clinical trials.

NC-6300, an epirubicin-incorporating micelle, extends the antitumor effect and reduces the cardiotoxicity of epirubicin.

Epirubicin is widely used to treat various human tumors. However, it is difficult to achieve a sufficient antitumor effect because of dosage limitation to prevent cardiotoxicity. We hypothesized that epirubicin-incorporating micelle would reduce cardiotoxicity and improve the antitumor effect. NC-6300 comprises epirubicin covalently bound to PEG polyaspartate block copolymer through an acid-labile hydrazone bond. The conjugate forms a micellar structure of 40-80 nm in diameter in an aqueous milieu. NC-6300 (10, 15 mg/kg) and epirubicin (10 mg/kg) were given i.v. three times to mice bearing s.c. or liver xenograft of human hepatocellular carcinoma Hep3B cells. Cardiotoxicity was evaluated by echocardiography in C57BL/6 mice that were given NC-6300 (10 mg/kg) or epirubicin (10 mg/kg) in nine doses over 12 weeks. NC-6300 showed a significantly potent antitumor effect against Hep3B s.c. tumors compared with epirubicin. Moreover, NC-6300 also produced a significantly longer survival rate than epirubicin against the liver orthotopic tumor of Hep3B. With respect to cardiotoxicity, epirubicin-treated mice showed significant deteriorations in fractional shortening and ejection fraction. In contrast, cardiac functions of NC-6300 treated mice were no less well maintained than in control mice. This study warrants a clinical evaluation of NC-6300 in patients with hepatocellular carcinoma or other cancers.

Treatment strategy for reducing the risk of rituximab-induced cytokine release syndrome in patients with intravascular large B-cell lymphoma: a case report and review of the literature.

INTRODUCTION: Intravascular large B-cell lymphoma is a rare aggressive disseminated disease characterized by the presence of lymphoma cells in small vessels without lymphadenopathy. Rituximab, a novel monoclonal antibody against the CD20 B-cell antigen, has been reported to be effective in treating intravascular large B-cell lymphoma. However, adverse events have been reported in association with rituximab infusion. CASE PRESENTATION: We report the case of a 54-year-old Japanese man diagnosed with Asian variant intravascular large B-cell lymphoma who died within five hours of the initiation of a first course of chemotherapy including rituximab. Autopsy results suggested that the patient died of severe systemic inflammatory response syndrome. A literature review revealed that rituximab administered during the second course of chemotherapy (instead of during the first course) appears to reduce the incidence of infusion reactions (from 48% to 15%) without altering the frequency of complete remission outcomes. CONCLUSIONS: Our data indicate that the incidence of adverse reactions to rituximab can be markedly decreased if the tumor load is first reduced with an initial course of chemotherapy excluding rituximab. Future prospective studies of the timing of rituximab administration are warranted.

NC-6301, a polymeric micelle rationally optimized for effective release of docetaxel, is potent but is less toxic than native docetaxel in vivo.

Drug release rate is an important factor in determining efficacy and toxicity of nanoscale drug delivery systems. However, optimization of the release rate in polymeric micellar nanoscale drug delivery systems has not been fully investigated. In this study NC-6301, a poly(ethylene glycol)-poly(aspartate) block copolymer with docetaxel (DTX) covalently bound via ester link, was synthesized with various numbers of DTX molecules bound to the polymer backbone. The number of DTX molecules was determined up to 14 to achieve an optimal release rate, based upon the authors' own pharmacokinetic model using known patient data. Efficacy and toxicity of the formulation was then tested in animals. When administered three times at 4-day intervals, the maximum tolerated doses of NC-6301 and native DTX were 50 and 10 mg/kg, respectively, in nude mice. Tissue distribution studies of NC-6301 in mice at 50 mg/kg revealed prolonged release of free DTX in the tumor for at least 120 hours, thus supporting its effectiveness. Furthermore, in cynomolgus monkeys, NC-6301 at 6 mg/kg three times at 2-week intervals showed marginal toxicity, whereas native DTX, at 3 mg/kg with the same schedule, induced significant decrease of food consumption and neutrophil count. NC-6301 at 50 mg/kg in mice also regressed a xenografted tumor of MDA-MB-231 human breast cancer. Native DTX, on the other hand, produced only transient and slight regression of the same tumor xenograft. NC-6301 also significantly inhibited growth of OCUM-2MLN human scirrhous gastric carcinoma in an orthotopic mouse model. Total weight of metastatic lymph nodes was also reduced. In conclusion, NC-6301 with an optimized release rate improved the potency of DTX while reducing its toxicity.

Prolonged circulation and in vivo efficacy of recombinant human granulocyte colony-stimulating factor encapsulated in polymeric micelles.

To improve the pharmacokinetics of granulocyte colony-stimulating factor (G-CSF) and decrease dosing frequency, polyethylene glycol polyglutamate block copolymers were used as delivery carriers. The block copolymers are partially substituted with hydrophobic octyl or benzyl groups to form a micellar structure in aqueous media and encapsulate the protein. G-CSF is encapsulated in the polymeric micelles with a diameter of 60-70nm. The present study was designed to evaluate the plasma pharmacokinetics, G-CSF release and in vivo efficacy of G-CSF-encapsulating micelles. Pharmacokinetic studies in rats showed highly enhanced plasma retention of the micelles compared with native G-CSF. The AUC (area under the curve) of the octyl-based polymer formulation showed a 5-fold increase, compared with native G-CSF. Size-exclusion chromatography of the blood from rats injected with the micelles demonstrated the release of G-CSF from the micelles in the blood circulation. The pharmacokinetic behavior supports the in vivo studies showing that the micelles display a comparable efficacy to PEGylated G-CSF. Simultaneous pharmacokinetic analysis of released and encapsulated G-CSF plasma levels showed that the G-CSF release occurs with the first-order kinetics and the half-life is 4.8h. In conclusion, G-CSF is endowed by the polymeric micelles with prolonged half-life and increased efficacy without any chemical modification.

Improved anti-tumor activity of stabilized anthracycline polymeric micelle formulation, NC-6300.

Anthracyclines have long been considered to be among the most active agents clinically available for the treatment of breast cancer despite their toxicity. To improve their pharmacological profiles, a new macromolecular prodrug, denoted NC-6300, was synthesized. NC-6300 comprises epirubicin covalently bound to polyethylene-glycol polyaspartate block copolymer through an acid-labile hydrazone bond. The conjugate forms a micellar structure spontaneously in aqueous media with a diameter of 60-70 nm. The block copolymers are partially substituted with hydrophobic benzyl groups to stabilize the micellar structure. The present study was designed to confirm that polymeric micelles incorporating epirubicin through an acid-labile linker improve the therapeutic index and achieve a broad range of therapeutic doses. Pharmacokinetic studies in rats showed highly enhanced plasma retention of NC-6300 compared with native epirubicin. The maximal tolerated doses in mice of NC-6300 and native epirubicin were 25 and 9 mg/kg, respectively, when administered three times with a 4-day interval between each dose. NC-6300 at 15 and 20 mg/kg with the same administration schedule regressed a Hep3B human hepatic tumor with slight and transient bodyweight loss. Remarkably, NC-6300 also inhibited growth of an MDA-MB-231 human breast tumor at the same dosage. In contrast, native epirubicin at 7 mg/kg administered three times with a 4-day interval was only able to slow tumor growth. Tissue distribution studies of NC-6300 showed efficient free epirubicin released in the tumor at 74% by area under the concentration-time curve (AUC) evaluation, supporting the effectiveness of NC-6300. In conclusion, NC-6300 improved the potency of epirubicin, demonstrating the advantage of NC-6300 attributable to the efficient drug release in the tumor.

Early immune reaction after reduced-intensity cord-blood transplantation for adult patients.

BACKGROUND: To investigate immune reactions after reduced-intensity cord-blood transplantation (RI-CBT). MATERIALS AND METHODS: We reviewed medical records of 57 adult RI-CBT recipients. Preparative regimen comprised fludarabine, total-body irradiation, and either melphalan (n=51) or busulfan (n=6). Graft-versus-host disease (GvHD) prophylaxis was cyclosporine. PostRI-CBT immune reactions were classified according to time course: pre-engraftment immune reactions (PIR), engraftment syndrome (ES), and GvHD. RESULTS: Forty-five patients achieved engraftment at a median of day 19. PIR was characterized by high-grade fever and weight gain and developed on a median of day 9 in 35 of the 45 evaluable patients, including 3 who did not achieve engraftment. PIR subsided spontaneously in 12 patients, whereas corticosteroids were required in the other 23. ES and grade I to IV acute GvHD developed in 36 and 29 patients, respectively. GvHD could not be distinguished from preceding PIR or ES in 10 patients. Causes of the 32 nonrelapse mortalities included GvHD (n=5) and PIR (n=1). There were no significant differences in relapse and nonrelapse deaths between patients with PIR and those without it (18% vs. 5%, and 60% vs. 65%, respectively). CONCLUSIONS: Immune reactions after RI-CBT can be categorized into three distinct subtypes.

[Fungal prophylaxis following reduced-intensity stem cell transplantation (RIST)].

Hematopoietic stem cell transplantation has been established as a curative treatment for advanced hematologic malignancies. Transplantation with a reduced-intensity conditioning regimen has been developed. The minimal toxicity of reduced-intensity stem cell transplantation (RIST) has made transplantation available for patients of advanced age or with organ dysfunction. The response of malignant lymphoma and some solid tumors to RIST has been observed. RIST with unrelated donors and umbilical cord blood has been studied. Fungal infection is an important complication of RIST. Since the prognosis of fungal infection is poor, the management has been focused on its prophylaxis. Given recent progression in RIST management, the strategy of infectious prophylaxis has also changed. Equipment in the hospital is important for fungal infection; however, the median day of the development of fungal infection is day 100, when most patients are followed as outpatients. The focus of fungal management after RIST is oral antifungal agents rather than in-hospital equipment. Various antifungal agents have recently been developed and applied for clinical use. Many antifungals have been developed simultaneously for the first time. A major change in antifungal management will probably occur in the next several years.

Heparin-induced thrombocytopenia and thrombosis in a patient with polycythemia vera.

A 75-year-old Japanese woman with polycythemia vera was admitted to our hospital in January 2003 with suspected pulmonary thromboembolism. After administration of heparin, platelet count decreased from 1,694 x 10(9)/l on admission to 60 x 10(9)/l on hospital day 14. The patient developed acute limb embolism and transient cerebral ischemic attack on days 17 and 25, respectively. Signs and symptoms mimicked those of disseminated intravascular coagulation. Antibodies against heparin and platelet factor 4 complexes were detected in serum, and a diagnosis of heparin-induced thrombocytopenia and thrombosis was made. Argatroban treatment improved thrombocytopenia and hypercoagulable state.

Early central nervous system complications after reduced-intensity stem cell transplantation.

To investigate clinical characteristics of early central nervous system (CNS) complications after reduced-intensity stem cell transplantation (RIST), we reviewed the medical records of 232 patients who had undergone RIST for hematologic diseases at our institutions between September 1999 and June 2003. All patients had received purine analog-based preparative regimens. Stem cell sources comprised granulocyte colony-stimulating factor-mobilized blood from HLA-identical or 1 locus-mismatched related donors (n = 151), unrelated bone marrow (n = 44), or unrelated cord blood (n = 37). Graft-versus-host disease prophylaxis incorporated cyclosporine with or without methotrexate. Diagnosis of CNS complications was based on clinical, radiologic, and microbiological findings. CNS complications occurred in 18 patients (7.8%), with a median onset of 22 days, and were infectious (n = 1), metabolic (n = 15), or cerebrovascular (n = 2). Symptoms included seizures (n = 7), visual disturbance (n = 2), headache (n = 8), nausea (n = 8), vomiting (n = 6), impaired consciousness (n = 16), and hemiparesis (n = 3). Complications improved promptly in 10 patients, and 8 patients died without improvement within 30 days. Multivariate analysis with logistic regression identified umbilical cord blood transplantation as a significant risk factor for early CNS complications (odds ratio, 14.5; 95% confidence interval, 3.7-56.9; P <.0001). CNS complications are a significant problem after RIST, particularly with umbilical cord blood. Limbic encephalopathy is an unrecognized subtype of neurotoxicity after umbilical cord blood transplantation.

Successful engraftment after reduced-intensity umbilical cord blood transplantation for adult patients with advanced hematological diseases.

PURPOSE: The purpose of this research was to evaluate the feasibility of reduced-intensity unrelated cord-blood transplantation (RI-UCBT) in adult patients with advanced hematological diseases. EXPERIMENTAL DESIGN: Thirty patients (median age, 58.5 years; range, 20-70 years) with advanced hematological diseases underwent RI-UCBT at Toranomon Hospital between September 2002 and August 2003. Preparative regimen composed of fludarabine 25 mg/m(2) on days -7 to -3, melphalan 80 mg/m(2) on day -2, and 4 Gy total body irradiation on day -1. Graft-versus-host disease prophylaxis was composed of cyclosporin alone. RESULTS: Twenty-six patients achieved primary neutrophil engraftment after a median of 17.5 days. Median infused total cell dose was 3.1 x 10(7)/kg (range, 2.0-4.3 x 10(7)/kg). Two transplant-related mortalities occurred within 28 days of transplant, and another 2 patients displayed primary graft failure. Cumulative incidence of complete donor chimerism at day 60 was 93%. Grade II-IV acute graft-versus-host disease occurred in 27% of patients, with median onset 36 days. Primary disease recurred in 3 patients, and transplant-related mortality within 100 days was 27%. Estimated 1-year overall survival was 32.7%. Excluding 7 patients with documented infection, 19 patients displayed noninfectious fever before engraftment (median onset, day 9). Manifestations included high-grade fever, eruption, and diarrhea. The symptoms responded well to corticosteroid treatments in 7 of 13 treated patients. CONCLUSION: This study demonstrated the feasibility of RI-UCBT in adults.

Thalidomide treatment for immunoglobulin D multiple myeloma in a patient on chronic hemodialysis.

A 64-year-old Japanese man suffering from IgD lambda myeloma and renal failure requiring chronic hemodialysis was treated with thalidomide. Serum IgD concentration was 4,050 mg/dl and myeloma cells constituted 95.6% of nucleated cells in bone marrow at the start of treatment. These parameters improved markedly to 1,590 mg/dl and 22.0%, respectively, in the 4 months immediately prior to his death due to pneumonia. Thalidomide caused peripheral neuropathy and constipation at a dose of 100 mg daily in the first week of treatment, but adverse effects resolved upon dose reduction. Thalidomide represents a valid therapeutic option for some myeloma patients receiving hemodialysis.

Pyomyositis as a focus of infection in hematological disorders: a report of 3 cases.

The cases of 3 patients with pyomyositis associated with hematological disorders are reported. A 40-year-old man in the blastic phase of chronic myelogenous leukemia and 2 men aged 46 and 71 years with neutropenia due to myelodysplastic syndromes all reported high fever and severe local myalgia and had marked elevation of C-reactive protein. Magnetic resonance imaging revealed muscle abscesses or fasciitis, and the findings led to the diagnosis of pyomyositis. Methicillin-resistant Staphylococcus aureus was isolated from the abscesses of 2 patients, and surgical drainage proved more effective than did antimicrobial agents. It should be recognized that pyomyositis is a possible source of infection in patients with hematological disorders.

Clinical significance of phenotypic features of blasts in patients with myelodysplastic syndrome.

Knowledge of the blast phenotype in myelodysplastic syndrome (MDS) would be valuable, as in other malignancies, but remains sparse. This is mainly because MDS blasts are a minor population in clinical samples, making analysis difficult. Thus, for this blast phenotype study, we prepared blast-rich specimens (using a new density centrifugation reagent for harvesting blasts) from blood and marrow samples of 95 patients with various MDS subtypes and 21 patients with acute leukemia transformed from MDS (AL-MDS). Flow cytometry revealed that a high proportion of the enriched blast cells (EBCs) from almost all patients showed an immunophenotype of committed myeloid precursors (CD34(+)CD38(+)HLA-DR(+)CD13(+)CD33(+)), regardless of the disease subtype. The cytochemical reaction for myeloperoxidase was negative in 58% of the cases. Thus, the EBC phenotype is more immature in MDS than in de novo acute myeloid leukemia. MDS EBCs often coexpressed stem cell antigens and late-stage myeloid antigens asynchronously, but rarely expressed T- and B-lymphoid cell-specific antigens. Markers for myeloid cell maturation (CD10 and CD15) were more prevalent on EBCs from low-risk MDS (refractory anemia [RA] and RA with ringed sideroblasts), whereas markers for myeloid cell immaturity (CD7 and CD117) were more prevalent on EBCs from high-risk MDS (chronic myelomonocytic leukemia, RA with excess blasts [RAEB], and RAEB in transformation) and AL-MDS. A shift to a more immature phenotype of EBCs, accompanying disease progression, was also documented by sequential phenotyping of the same patients. Further, CD7 positivity of EBCs was an independent variable for a poor prognosis in MDS. These data represent new, valuable information regarding MDS.