Clinical phase II and III studies of an AS03-adjuvanted H5N1 influenza vaccine produced in an EB66® cell culture platform.

BACKGROUND: We have developed an AS03-adjuvanted H5N1 influenza vaccine produced in an EB66® cell culture platform (KD-295). OBJECTIVES: In accordance with Japanese guidelines for development of pandemic prototype vaccines, the phase II study was conducted in a double-blind, randomized, parallel-group comparison study and the phase III study was conducted in an open-label, non-randomized, uncontrolled study. METHODS: Healthy adult volunteers aged 20 - 64 years enrolled in the phase II and III studies (N = 248 and N = 369) received KD-295 intramuscularly twice with a 21-day interval. After administration, immune response and adverse events were evaluated. In the phase II study, four different vaccine formulations were compared: MA (3.75 µg hemagglutinin [HA] antigen + AS03 adjuvant system), MB (3.75 µg HA + 1/2AS03), HA (7.5 µg HA + AS03), and HB (7.5 µg HA + 1/2AS03). In the phase III study, the MA formulation was further evaluated. RESULTS: In the phase II study, all four vaccine formulations were well-tolerated and no SAE related to vaccination were observed. The MA formulation was slightly more immunogenic and less reactogenic among the vaccine formulations. Therefore, the MA formulation was selected for the phase III study, and it was well-tolerated and no serious adverse drug reactions were observed. The vaccine fulfilled the three immunogenicity criteria described in the Japanese guidelines. CONCLUSIONS: These data indicate that the MA formulation of KD-295 was well-tolerated and highly immunogenic and it can be considered a useful pandemic and pre-pandemic influenza vaccine.

A clinical phase I study of an EB66 cell-derived H5N1 pandemic vaccine adjuvanted with AS03.

BACKGROUND: We conducted a phase I clinical trial of a cell culture-derived AS03-adjuvanted influenza vaccine containing HA antigen (A/Indonesia/05/2005(H5N1)/PR8-IBCDC-RG2) derived from EB66 cells (KD-295). METHODS: Healthy male adult volunteers (20-40 years old, N=60) enrolled in the study were divided into 3 groups, the MA group (3.8 µg of HA+AS03), HA group (7.5 µg of HA+AS03), and 1/2 MA group (half the volume of the MA group), and received KD-295 intramuscularly twice with a 21-day interval. After administration of KD-295, adverse events, clinical laboratory parameters, and immune response to the vaccine strain and heterologous virus strains were evaluated. RESULTS: No severe adverse events leading to discontinuation of vaccine administration occurred. The vaccine was well-tolerated. There was no dose dependency in the rate, timing, or duration of the adverse events. Immunogenicity of the vaccines was evaluated by HI (hemagglutination inhibition) assay, which confirmed that the antibody response to the vaccine strain and heterologous strain in all groups met the three criteria for immunogenicity described in the Japanese guidelines for development of a pandemic prototype vaccine. We also measured the neutralizing antibody titers against several virus strains, and confirmed a significant rise in antibody levels to both the vaccine strain and heterologous strains. CONCLUSION: The EB66-derived H5N1 influenza vaccine adjuvanted with AS03 elicited a broad cross-reactive antibody response among H5N1 strains with acceptable reactogenicity. Therefore, KD-295 can be considered a useful pandemic and pre-pandemic influenza vaccine candidate.

The protective effect of selenoprotein P on injury in rat liver transplantation.

BACKGROUND/AIMS: Selenoprotein P (SeP), a plasma protein, is considered to have a protective effect against various organ damages. We investigated whether addition of SeP to storage solution could attenuate cold ischemia/reperfusion injury (IRI) in rat liver transplantation. METHODOLOGY: After 24 hrs cold preservation in either University of Wisconsin (UW) solution with or without SeP (1 micromol/L or 10 micromol/L), the liver was flushed with warm lactated Ringer's solution. Alanine aminotransferase (ALT) level in the venous effluent was measured. Orthotopic liver transplantation (OLTx) was then performed after the same preservation as above. Blood biochemical features and tissue lipid peroxide levels were measured after OLTx, and morphometric changes analyzed by hematoxylin and eosin, and terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end-labeling (TUNEL) staining. RESULTS: ALT levels in effluent in the SeP 10 group were significantly lower than those in other groups. Serum aspartate aminotransferase (AST) and lactate dehydrogenase (LDH) were significantly decreased in the SeP 10 group. Histological examinations showed amelioration of sinusoidal damage in the SeP 10 group at 1 hr after OLTx. Percentages of necrotic areas and apoptotic sinusoidal endothelial cells were decreased in the SeP 10 group. CONCLUSIONS: The addition of SeP to UW solution attenuates injury in OLTx.

Successful treatment of collagen-induced arthritis in non-human primates by chimeric anti-osteopontin antibody.

The presence of thrombin-cleaved form of osteopontin well correlated with various inflammatory disease activities in not only rodents, but also humans. We previously demonstrated that the blocking of the interaction of a cryptic epitope within osteopontin, which is exposed by thrombin cleavage, with its integrins by specific antibody recognizing cryptic epitope of mouse osteopontin, could significantly inhibits the development of arthritis in mice. We generated a murine monoclonal antibody, 2K1, specifically recognizing a cryptic epitope of human osteopontin, SVVYGLR. We constructed a chimeric antibody, C2K1 in which variable region of 2K1 was fused with human IgG1 constant region. In the present study, we investigated whether the therapeutic administration of C2K1 could ameliorate the established collagen-induced arthritis in cynomolgus monkey. Thus, C2K1 was injected after the onset of arthritis. The inhibition of joint swelling by C2K1 became evident at 4 to 5 weeks after initiation of arthritis, when blood level of C2K1 was peaked. Joint swelling reappeared along with the sharp decline of C2K1 blood levels at 6 weeks. Importantly, destruction of bone and cartilage in joints was still significantly prevented at 10 weeks when blood level of C2K1 was quite low if any and anti-C2K1 antibody emerged. These results demonstrate that neutralizing antibody against the cryptic epitope of osteopontin can be a future therapeutic choice for patients with rheumatoid arthritis.

Identification of selenoprotein P fragments as a cell-death inhibitory factor.

Megakaryoblastoma (Dami cells) cultured in a serum-free medium containing albumin, proliferated for three days but died on the fourth day. This cell death was not observed when human plasma was added, suggesting that human plasma contains a cell-death inhibitory factor. In order to identify this factor, we purified it from human plasma. N-terminal amino acid sequence analysis revealed that this factor is a mixture of C-terminal fragments of selenoprotein P, a major selenocysteine-containing protein in plasma. The specific activity (unit per pmol of selenium) of selenoprotein P fragments protein was 15-fold and 1900-fold higher than that of the full-length SeP and sodium selenite, respectively.

Expression and function of NJ-1 surface antigen in megakaryopoiesis.

Immunostaining with NJ-1 monoclonal antibody (MoAb) revealed that NJ-1 is expressed on megakaryocytes (MKs). NJ-1-positive and lineage-negative progenitor cells have a higher potency to proliferate and differentiate into MKs. MKs were divided into NJ-1(+)MKs and NJ-1(-)MKs. NJ-1(+)MKs are immature MKs because of their low potential to generate pro-platelets. When cultured CD41-positive MK cells were analyzed with RT-PCR, we found that the expression of NJ-1 is down-regulated. NJ-1(+)MKs have a high adherent potential to endothelial cells comparing with NJ-1(-)MKs, and this binding ability could be inhibited by the NJ-1-Fc fusion protein. We hypothesize that NJ-1(+)MKs are immature MKs and the NJ-1 molecule is involved in MK adhesion to endothelial cells.