Synthetic virus seeds for improved vaccine safety: Genetic reconstruction of poliovirus seeds for a PER.C6 cell based inactivated poliovirus vaccine.

Safety of vaccines can be compromised by contamination with adventitious agents. One potential source of adventitious agents is a vaccine seed, typically derived from historic clinical isolates with poorly defined origins. Here we generated synthetic poliovirus seeds derived from chemically synthesized DNA plasmids encoding the sequence of wild-type poliovirus strains used in marketed inactivated poliovirus vaccines. The synthetic strains were phenotypically identical to wild-type polioviruses as shown by equivalent infectious titers in culture supernatant and antigenic content, even when infection cultures are scaled up to 10-25L bioreactors. Moreover, the synthetic seeds were genetically stable upon extended passaging on the PER.C6 cell culture platform. Use of synthetic seeds produced on the serum-free PER.C6 cell platform ensures a perfectly documented seed history and maximum control over starting materials. It provides an opportunity to maximize vaccine safety which increases the prospect of a vaccine end product that is free from adventitious agents.

Scale-down of the inactivated polio vaccine production process.

The anticipated increase in the demand for inactivated polio vaccines resulting from the success in the polio eradication program requires an increase in production capacity and cost price reduction of the current inactivated polio vaccine production processes. Improvement of existing production processes is necessary as the initial process development has been done decades ago. An up-to-date lab-scale version encompassing the legacy inactivated polio vaccine production process was set-up. This lab-scale version should be representative of the large scale, meaning a scale-down model, to allow experiments for process optimization that can be readily applied. Initially the separate unit operations were scaled-down at setpoint. Subsequently, the unit operations were applied successively in a comparative manner to large-scale manufacturing. This allows the assessment of the effects of changes in one unit operation to the consecutive units at small-scale. Challenges in translating large-scale operations to lab-scale are discussed, and the concessions that needed to be made are described. The current scale-down model for cell and virus culture (2.3-L) presents a feasible model with its production scale counterpart (750-L) when operated at setpoint. Also, the current scale-down models for the DSP unit operations clarification, concentration, size exclusion chromatography, ion exchange chromatography, and inactivation are in agreement with the manufacturing scale. The small-scale units can be used separately, as well as sequentially, to study variations and critical product quality attributes in the production process. Finally, it is shown that the scale-down unit operations can be used consecutively to prepare trivalent vaccine at lab-scale with comparable characteristics to the product produced at manufacturing scale.

Biotechnology and genetic engineering in the new drug development. Part II. Monoclonal antibodies, modern vaccines and gene therapy.

Monoclonal antibodies, modern vaccines and gene therapy have become a major field in modern biotechnology, especially in the area of human health and fascinating developments achieved in the past decades are impressive examples of an interdisciplinary interplay between medicine, biology and engineering. Among the classical products from cells one can find viral vaccines, monoclonal antibodies, and interferons, as well as recombinant therapeutic proteins. Gene therapy opens up challenging new areas. In this review, a definitions of these processes are given and fields of application and products, as well as the future prospects, are discussed.

Multivariate data analysis on historical IPV production data for better process understanding and future improvements.

Historical manufacturing data can potentially harbor a wealth of information for process optimization and enhancement of efficiency and robustness. To extract useful data multivariate data analysis (MVDA) using projection methods is often applied. In this contribution, the results obtained from applying MVDA on data from inactivated polio vaccine (IPV) production runs are described. Data from over 50 batches at two different production scales (700-L and 1,500-L) were available. The explorative analysis performed on single unit operations indicated consistent manufacturing. Known outliers (e.g., rejected batches) were identified using principal component analysis (PCA). The source of operational variation was pinpointed to variation of input such as media. Other relevant process parameters were in control and, using this manufacturing data, could not be correlated to product quality attributes. The gained knowledge of the IPV production process, not only from the MVDA, but also from digitalizing the available historical data, has proven to be useful for troubleshooting, understanding limitations of available data and seeing the opportunity for improvements.

Production, testing and perspectives of IPV and IPV combination vaccines: GSK biologicals' view.

GSK Biologicals has been involved in the production of Polio vaccine since the early start of Polio vaccination, beginning with the first generation of Inactivated Polio Vaccine (IPV). Over time, the company has developed solid industrial experience and knowledge that significantly contributes today to the quality of our Polio vaccines. GSK Biologicals' current IPV is now routinely produced according to the process defined by Van Wezel (RIVM) in the late seventies, using Vero cells and micro-carrier technology in bioreactors. In addition to compliance with current requirements (World Health Organization, European Pharmacopoeia, Code of Federal Regulations USA), the quality of the routine vaccine is guaranteed by numerous additional data related to the characterization, to the consistency, and to the validation of the process and the testing. This supplementary data package will allow, for instance, for the application of the in vitro potency testing for routine release instead of the in vivo testing. The present views on the Polio vaccine strategy for the post eradication era have portrayed a very limited role for the current IPV. The main reasons relate to post-eradication bio-containment needs and to production capacity and costs. A reevaluation of the classic approach taken to the use of the current IPV produced from wild type polio strains positions this vaccine as a real alternative to other strategies, allowing us to take advantage of the excellent performance of IPV over many years.

Development of inactivated poliovirus vaccine derived from Sabin strains.

In the course of Sabin-inactivated poliovirus vaccine (S-IPV) development, we have established high-yield virus production techniques based on Vero cell micro-carrier cultures. Development of specific ELISA tests to quantify the antigen content of S-IPV has been achieved. To adjust the immunogenicity of S-IPV so as to be comparable with the conventional-IPV, a new formulation was determined using a potency test using rats. The reformulated S-IPV was shown to be efficacious for the immunization of monkeys.

Establishment of European Pharmacopoeia BRP batch 2 for inactivated poliomyelitis vaccine for in vitro D antigen assay.

A collaborative study was initiated by the European Directorate for the Quality of Medicines (EDQM) to assign a potency value for the candidate Ph Eur BRP batch 2 against the 2nd International Standard (IS) in order to replace the dwindling stocks of Ph Eur BRP batch 1. The candidate material is a concentrated trivalent bulk (Type 1 (Mahoney), Type 2 (MEF1) and Type 3 (SAUKETT)) from a commercially available IPV vaccine. Nine laboratories participated in the collaborative study. Eight laboratories reported results. Participants performed in-house ELISA assays on the candidate BRP, the 2nd International Standard (IS) and the current BRP (BRP batch 1). An additional sample was included to acquire information on the correlation between the in vitro and in vivo assays based on comparison with a previous study. Results of that comparison are included as an annex. Potency estimates were satisfactory in terms of repeatability and reproducibility, however the estimates for the 2nd IS were significantly lower than those for Ph Eur BRP batch 1. These two reference standards are derived from the same material and were originally assigned the same potency value after a joint study run by EDQM and the WHO in 1994. A reconciliation study was therefore designed to determine if the IS stored at NIBSC and the IS which had been sent from NIBSC to EDQM for use in the initial study were equivalent. 3 of the laboratories from the initial study participated. Results revealed no significant difference between the 2nd IS stocks stored in the two different locations at NIBSC nor between BRP batch 1 and the standards stored at NIBSC for types 1 and 2. For type 3 the 2nd IS standards stored at NIBSC are 13 % less potent than the Ph Eur BRP batch 1. The 2nd IS which had been shipped from NIBSC to EDQM was significantly less potent than BRP batch 1 and the 2nd ISs stored at NIBSC for all three types, confirming the observation of the initial study. Possible explanations for this apparent loss of potency of the 2nd IS used in the study are under investigation. Since Ph Eur BRP batch 1 and the 2nd IS in stock at NIBSC appear no more different than when their original potency assignment was made at their establishment, and since the 2nd IS standard used in the initial part of this study was compromised, a consensus potency value for the candidate BRP was determined using Ph Eur BRP batch 1 as the reference standard. The candidate material was therefore assigned a potency of 320-67-282 D Antigen units/ml (IU) for types 1, 2 and 3 respectively. A stability monitoring program will be initiated. The candidate material was adopted by the European Pharmacopoeia Commission at its session in March 2003 as European Pharmacopoeia IPV vaccine BRP batch 2 for D Ag in vitro assay.