Process development of a New Haemophilus influenzae type b conjugate vaccine and the use of mathematical modeling to identify process optimization possibilities.

Vaccination is one of the most successful public health interventions being a cost-effective tool in preventing deaths among young children. The earliest vaccines were developed following empirical methods, creating vaccines by trial and error. New process development tools, for example mathematical modeling, as well as new regulatory initiatives requiring better understanding of both the product and the process are being applied to well-characterized biopharmaceuticals (for example recombinant proteins). The vaccine industry is still running behind in comparison to these industries. A production process for a new Haemophilus influenzae type b (Hib) conjugate vaccine, including related quality control (QC) tests, was developed and transferred to a number of emerging vaccine manufacturers. This contributed to a sustainable global supply of affordable Hib conjugate vaccines, as illustrated by the market launch of the first Hib vaccine based on this technology in 2007 and concomitant price reduction of Hib vaccines. This paper describes the development approach followed for this Hib conjugate vaccine as well as the mathematical modeling tool applied recently in order to indicate options for further improvements of the initial Hib process. The strategy followed during the process development of this Hib conjugate vaccine was a targeted and integrated approach based on prior knowledge and experience with similar products using multi-disciplinary expertise. Mathematical modeling was used to develop a predictive model for the initial Hib process (the 'baseline' model) as well as an 'optimized' model, by proposing a number of process changes which could lead to further reduction in price. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:568-580, 2016.

Use of immuno assays during the development of a Hemophilus influenzae type b vaccine for technology transfer to emerging vaccine manufacturers.

Quality control of Hemophilus Influenzae type b (Hib) conjugate vaccines is mainly dependent on physicochemical methods. Overcoming sample matrix interference when using physicochemical tests is very challenging, these tests are therefore only used to test purified samples of polysaccharide, protein, bulk conjugate, and final product. For successful development of a Hib conjugate vaccine, several ELISA (enzyme-linked immunosorbent assay) methods were needed as an additional tool to enable testing of in process (IP) samples. In this paper, three of the ELISA's that have been very valuable during the process development, implementation and scaling up are highlighted. The PRP-ELISA, was a very efficient tool in testing in process (IP) samples generated during the development of the cultivation and purification process of the Hib-polysaccharide. The antigenicity ELISA, was used to confirm the covalent linkage of PRP and TTd in the conjugate. The anti-PRP IgG ELISA was developed as part of the immunogenicity test, used to demonstrate the ability of the Hib conjugate vaccine to elicit a T-cell dependent immune response in mice. ELISA methods are relatively cheap and easy to implement and therefore very useful during the development of polysaccharide conjugate vaccines.

Preclinical evaluation of a Haemophilus influenzae type b conjugate vaccine process intended for technology transfer.

Introduction of Haemophilus influenzae type b (Hib) vaccine in low- and middle-income countries has been limited by cost and availability of Hib conjugate vaccines for a long time. It was previously recognized by the Institute for Translational Vaccinology (Intravacc, originating from the former Vaccinology Unit of the National Institute of Public Health [RIVM] and the Netherlands Vaccine Institute [NVI]) that local production of a Hib conjugate vaccine would increase the affordability and sustainability of the vaccine and thereby help to speed up Hib introduction in these countries. A new affordable and a non-infringing production process for a Hib conjugate vaccine was developed, including relevant quality control tests, and the technology was transferred to a number of vaccine manufacturers in India, Indonesia, and China. As part of the Hib technology transfer project managed by Intravacc, a preclinical toxicity study was conducted in the Netherlands to test the safety and immunogenicity of this new Hib conjugate vaccine. The data generated by this study were used by the technology transfer partners to accelerate the clinical development of the new Hib conjugate vaccine. A repeated dose toxicity and local tolerance study in rats was performed to assess the reactogenicity and immunogenicity of a new Hib conjugate vaccine compared to a licensed vaccine. The results showed that the vaccine was well tolerated and immunogenic in rats, no major differences in both safety and immunogenicity in rats were found between the vaccine produced according to the production process developed by Intravacc and the licensed one. Rats may be useful to verify the immunogenicity of Hib conjugate vaccines and for preclinical evaluation. In general, nonclinical evaluation of the new Hib conjugate vaccine, including this proof of concept (safety and immunogenicity study in rats), made it possible for technology transfer partners, having implemented the original process with no changes in the manufacturing process and vaccine formulation, to start directly with phase 1 clinical trials.

Development and technology transfer of Haemophilus influenzae type b conjugate vaccines for developing countries.

This paper describes the development of a Haemophilus influenzae type b (Hib) conjugate vaccine at the National Institute for Public Health and the Environment/Netherlands Vaccine Institute (RIVM/NVI, Bilthoven, The Netherlands), and the subsequent transfer of its production process to manufacturers in developing countries. In 1998, at the outset of the project, the majority of the world's children were not immunized against Hib because of the high price and limited supply of the conjugate vaccines, due partly to the fact that local manufacturers in developing countries did not master the Hib conjugate production technology. To address this problem, the RIVM/NVI has developed a robust Hib conjugate vaccine production process based on a proven model, and transferred this technology to several partners in India, Indonesia, Korea and China. As a result, emerging manufacturers in developing countries acquired modern technologies previously unavailable to them. This has in turn facilitated their approach to producing other conjugate vaccines. As an additional spin-off from the project, a World Health Organization (WHO) Hib quality control (QC) course was designed and conducted at the RIVM/NVI, resulting in an increased regulatory capacity for conjugate vaccines in developing countries at the National Regulatory Authority (NRA) level. For the local populations, this has translated into an increased and sustainable supply of affordable Hib conjugate-containing combination vaccines. During the course of this project, developing countries have demonstrated their ability to produce large quantities of high-quality modern vaccines after a successful transfer of the technology.

The Developing Countries Vaccine Manufacturers' Network (DCVMN) is a critical constituency to ensure access to vaccines in developing countries.

Six years after its establishment, the Developing Countries Vaccine Manufacturers' Network (DCVMN) has become the main representing body for emerging vaccine manufacturers from the developing world. The Network's main strategic priority (increase access to DPT-based combination vaccines containing vaccines against Hepatitis B (HepB) and Haemophilus influenzae type b (Hib)) has now come close to fulfillment due in part to the transfer of conjugation technology from The Netherlands Vaccine Institute (NVI) to various manufacturers of the Network. It is argued that at the international level more push mechanisms for product development involving DCVM are needed, including those promoting access to technology and transfer of technology, know how and technical skills from Organization for Economic Co-operation and Development (OECD) countries to developing countries. At the national level, governments of countries in which DCVMN manufacturers operate should provide more generous funding for all aspects of vaccines and immunization including incentives to manufacturers to develop and import new technologies. These two approaches will contribute to the long-term viability of domestic or regional vaccine manufacturing, which in itself is critical to ensure global equity of access to vaccines.

The consistency approach for the quality control of vaccines.

Current lot release testing of conventional vaccines emphasizes quality control of the final product and is characterized by its extensive use of laboratory animals. This report, which is based on the outcome of an ECVAM (European Centre for Validation of Alternative Methods, Institute for Health and Consumer Protection, European Commission Joint Research Centre, Ispra, Italy) workshop, discusses the concept of consistency testing as an alternative approach for lot release testing. The consistency approach for the routine release of vaccines is based upon the principle that the quality of vaccines is a consequence of a quality system and of consistent production of lots with similar characteristics to those lots that have been shown to be safe and effective in humans or the target species. The report indicates why and under which circumstances this approach can be applied, the role of the different stakeholders, and the need for international harmonization. It also gives recommendations for its implementation.

Technology transfer of Sabin-IPV to new developing country markets.

The Netherlands Vaccine Institute (NVI) developed the micro-carrier technology for large-scale production of IPV in the late 1960s and has used this technology successfully to produce IPV as well as DTP-IPV for the national immunization program in the Netherlands. As a public sector organization, and as one of the Millennium Development Goals, NVI has supported over the years access to vaccine technology like DTP and Hib for vaccine manufacturers in developing countries. In line with this role as a resource institute, NVI has recently been approached by a number of vaccine manufacturers, predominantly from developing countries, for transfer of IPV technology to meet the anticipated increase in demand for IPV following OPV cessation. Since WHO encourages new manufacturers to use the attenuated Sabin virus instead of wild polio strains in the production of IPV, NVI decided to respond positively to this WHO policy. The existing NVI experience in large-scale production of IPV and OPV using Vero cell based micro-carrier technology and its experience with experimental Sabin-IPV is an attractive start for the development of Sabin-IPV. This paper discusses the approach followed and the experience already gained in the project, as well as factors critical to its success.