Development of an animal component free production process for Sabin inactivated polio vaccine.

Inactivated polio vaccine production using attenuated Sabin strains (sIPV) instead of wild type polio viruses (cIPV) is an initiative encouraged by the World Health Organization. This use of attenuated viruses is preferred as it reduces risks related to potential outbreaks during IPV production. Previously, an sIPV production process was set up based on the cIPV production process. Optimizing this process while using only animal component free (ACF) substances allows reduction of operational costs and mitigates risks of adverse effects related with animal derived compounds. Here, development of a process for production of sIPV using only ACF compounds, is described. The upstream process required a change in cell growth medium from serum-containing medium to ACF medium, while virus production media remained the same as the already used M199 medium was free of animal components. In the downstream process multiple modifications in existing unit operations were made including addition of a diafiltration step prior to inactivation. After optimizing each unit operation, robustness of the whole process was demonstrated using design of experiments (DoE) methodology. By using DoE we were able to vary different process parameters across unit operations to assess the impact on our quality attributes. The developed process was robust as the observed variation for quality attributes due to differences in process parameters remained within specification. The resulting pilot process showed not only to be robust, but also to have a considerable higher product yield when compared to the serum containing sIPV process. Product yields are now comparable to the cIPV process based on using wild type polio viruses. Moreover, the potency of the produced vaccine was comparable that of cIPV vaccine. The developed ACF sIPV process can be transferred to vaccine manufacturers at the end-of pre-clinical development phase, at lab- or pilot scale, before production of clinical trial material.

Next generation inactivated polio vaccine manufacturing to support post polio-eradication biosafety goals.

Worldwide efforts to eradicate polio caused a tipping point in polio vaccination strategies. A switch from the oral polio vaccine, which can cause circulating and virulent vaccine derived polioviruses, to inactivated polio vaccines (IPV) is scheduled. Moreover, a manufacturing process, using attenuated virus strains instead of wild-type polioviruses, is demanded to enhance worldwide production of IPV, especially in low- and middle income countries. Therefore, development of an IPV from attenuated (Sabin) poliovirus strains (sIPV) was pursued. Starting from the current IPV production process based on wild type Salk strains, adaptations, such as lower virus cultivation temperature, were implemented. sIPV was produced at industrial scale followed by formulation of both plain and aluminium adjuvanted sIPV. The final products met the quality criteria, were immunogenic in rats, showed no toxicity in rabbits and could be released for testing in the clinic. Concluding, sIPV was developed to manufacturing scale. The technology can be transferred worldwide to support post polio-eradication biosafety goals.

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.

Inactivated polio vaccine development for technology transfer using attenuated Sabin poliovirus strains to shift from Salk-IPV to Sabin-IPV.

Industrial-scale inactivated polio vaccine (IPV) production dates back to the 1960s when at the Rijks Instituut voor de Volksgezondheid (RIV) in Bilthoven a process was developed based on micro-carrier technology and primary monkey kidney cells. This technology was freely shared with several pharmaceutical companies and institutes worldwide. In this contribution, the history of one of the first cell-culture based large-scale biological production processes is summarized. Also, recent developments and the anticipated upcoming shift from regular IPV to Sabin-IPV are presented. Responding to a call by the World Health Organization (WHO) for new polio vaccines, the development of Sabin-IPV was continued, after demonstrating proof of principle in the 1990s, at the Netherlands Vaccine Institute (NVI). Development of Sabin-IPV plays an important role in the WHO polio eradication strategy as biocontainment will be critical in the post-OPV cessation period. The use of attenuated Sabin strains instead of wild-type Salk polio strains will provide additional safety during vaccine production. Initially, the Sabin-IPV production process will be based on the scale-down model of the current, and well-established, Salk-IPV process. In parallel to clinical trial material production, process development, optimization and formulation research is being carried out to further optimize the process and reduce cost per dose. Also, results will be shown from large-scale (to prepare for future technology transfer) generation of Master- and Working virus seedlots, and clinical trial material (for phase I studies) production. Finally, the planned technology transfer to vaccine manufacturers in low and middle-income countries is discussed.

Characterization and standardization of Sabin based inactivated polio vaccine: proposal for a new antigen unit for inactivated polio vaccines.

GMP-batches of Sabin-IPV were characterized for their antigenic and immunogenic properties. Antigenic fingerprints of Sabin-IPV reveal that the D-antigen unit is not a fixed amount of antigen but depends on antibody and assay type. Instead of the D-antigen unit we propose standardization of IPV based on a combination of protein amount for dose and D-antigenicity for quality of the vaccine. Although Sabin-IPV type 2 is less immunogenic than regular wild type IPV type 2, the immunogenicity (virus neutralizing titers) per microgram antigen for Sabin-IPV type 2 is in the same order as for wild type serotypes 1 and 3. The latter observations are in line with data from human trials. This suggests that a higher dose of Sabin-IPV type 2 to compensate for the lower rat immunogenicity may not be necessary.