The JMU-SalVac-System: A Novel, Versatile Approach to Oral Live Vaccine Development.

Salmonella enterica Serovar Typhi Ty21a (Ty21a) is the only licensed oral vaccine against typhoid fever. Due to its excellent safety profile, it has been used as a promising vector strain for the expression of heterologous antigens for mucosal immunization. As the efficacy of any bacterial live vector vaccine correlates with its ability to express and present sufficient antigen, the genes for antigen expression are traditionally located on plasmids with antibiotic resistance genes for stabilization. However, for use in humans, antibiotic selection of plasmids is not applicable, leading to segregational loss of the antigen-producing plasmid. Therefore, we developed an oral Ty21a-based vaccine platform technology, the JMU-SalVac-system (Julius-Maximilians-Universität Würzburg) in which the antigen delivery plasmids (pSalVac-plasmid-series) are stabilized by a ΔtyrS/tyrS+-based balanced-lethal system (BLS). The system is made up of the chromosomal knockout of the essential tyrosyl-tRNA-synthetase gene (tyrS) and the in trans complementation of tyrS on the pSalVac-plasmid. Further novel functional features of the pSalVac-plasmids are the presence of two different expression cassettes for the expression of protein antigens. In this study, we present the construction of vaccine strains with BLS plasmids for antigen expression. The expression of cytosolic and secreted mRFP and cholera toxin subunit B (CTB) proteins as model antigens is used to demonstrate the versatility of the approach. As proof of concept, we show the induction of previously described in vivo inducible promoters cloned into pSalVac-plasmids during infection of primary macrophages and demonstrate the expression of model vaccine antigens in these relevant human target cells. Therefore, antigen delivery strains developed with the JMU-SalVac technology are promising, safe and stable vaccine strains to be used against mucosal infections in humans.

Three-year safety observation of subcutaneous administration of epoetin-zeta in patients with chronic renal anemia: Results from PASCO II study.

Epoetin has been used to treat patients with renal anemia since 1988. -Anti-erythropoietin antibody-mediated pure red cell aplasia (PRCA) has been associated with epoetin usage, and a PRCA incidence of 4.5 per 10,000 patient-years was observed for epoetin-α (Eprex) in 2002. The PASCO II study (post-authorization safety cohort observation of Retacrit and Silapo (epoetin-ζ) administered subcutaneously for the treatment of renal anemia) followed 6,346 patients (4,501 Retacrit (group R); 1,845 Silapo (group S)) for up to 3 years of subcutaneous treatment with the biosimilar epoetin-ζ. One PRCA in 1 (0.02%) patient in group R who tested positive for neutralizing antibodies was reported. Overall, 527 adverse events of special interest (AESI) including PRCA occurred in 418 (6.60%) patients, lack of efficacy occurred in 34 (0.54%), and thromboembolic events in 389 (6.14%) patients. 41 adverse drug reactions other than AESIs were reported in 28 (0.44%) patients. The exposure-adjusted incident rate of PRCA was 0.84 per 10,000 patient-years. This real-world study showed that among patients with renal anemia receiving subcutaneous administration of the biosimilar product epoetin-ζ, the incidence rate of PRCA was substantially below the risk observed in 2002 for Eprex and that there was no immunogenicity concern or other new safety concern.

Results from a safety cohort of patients with renal anemia receiving the biosimilar epoetinzeta: The PASCO I study.

BACKGROUND: Epoetin-zeta (epoetin-ζ) (sold as Retacrit™/Silapo™) is a biologic product that was approved by the European Medicines Agency in 2007 after demonstrating biosimilarity to its reference product epoetin-α (Eprex™), based on a comprehensive comparability exercise including extensive biophysical characterization and three double-blind randomized controlled trials. Since 2008, epoetin-ζ has been prescribed by physicians across Europe to treat anemia of renal disease in many thousands of patients. METHODS: Provided here are results of the PASCO I study (post-authorization safety cohort observation of silapo/retacrit (epoetin-ζ) administered intravenously for the treatment of renal anemia). The primary study endpoint was the frequency of adverse events of special interest (AESI) occurring in patients receiving epoetin-ζ over a 1-year study observation period. RESULTS: The safety set included 1,634 patients who received at least 1 dose of epoetin-ζ during the study period. These patients experienced AESI at these frequencies: clotting of artificial kidney 9.8%, lack of efficacy 2.3%, cerebrovascular events (including cerebrovascular accident, cerebral infarction, cerebral hemorrhage, and transient ischemic attack) 1.8%, myocardial infarction 1.7%, acute myocardial infarction 1.2%, clinically relevant hyperkalemia 0.4%, deep vein thrombosis 0.2%, convulsion 0.2%, hypertensive encephalopathy 0.1%, and pulmonary embolism 0.1%. No patients were reported as having anaphylactoid reactions, angioedema, erythropoietinneutralizing antibodies, or pure red cell aplasia. The median weekly follow-up dose of epoetin-ζ was 158.6 IU/kg. Mean hemoglobin concentration ranged between 11.3 and 11.7 g/dL. From the safety set, 228 patients died (14.0%), while 1,135 patients (74.9%; excluding 119 with data missing) continued treatment with epoetin-ζ following the 12-month observation. CONCLUSION: The PASCO I study contributes significantly to current knowledge about the frequency of adverse events associated with the use of epoetin-ζ for the treatment of renal anemia and demonstrates a pattern of adverse events comparable with data for other existing epoetin products in Europe.