The second Geneva Consensus: Recommendations for novel live TB vaccines.

Infection with Mycobacterium tuberculosis continues to be a major public health burden in most developing parts of the world and efforts to develop effective strategies for containing the disease remain a priority. It has long been evident that effective mass vaccination programmes are a cost effective and efficient approach to controlling communicable diseases in a public health setting and tuberculosis (TB) continues to be a major target. One approach with increasing acceptance is based upon on live mycobacterial vaccines, either as recombinant BCG or rationally attenuated M. tuberculosis, thus generating a new live TB vaccine. The Geneva Consensus published in March 2005 set out the opinion on priorities and requirements for developing live mycobacterial vaccines for Phase I trials. In the intervening period much progress has been made in both preclinical and clinical development of new TB vaccines and has provided the impetus for organising the second Geneva Consensus (held at WHO headquarters, April 2009) to discuss issues, including: i. Explore the regulatory requirements for live TB vaccines to enter Phase I trials, in particular those based on attenuated M. tuberculosis. Particular attention was paid to the characterisation and safety package likely to be required, including issues of attenuation, the presence of antibiotic resistance markers in live vaccines and the nature of any attenuated vaccine phenotype. ii. To identify the general criteria for further clinical development from Phase I through to Phase III. iii. Obtain a perspective of the regulatory landscape of developing countries where Phase II and III trials are to be held. iv. Review manufacturing considerations for live TB vaccines and relevance of the WHO and European Pharmacopeia guidelines and requirements for BCG vaccine. v. Consider requirements and associated issues related to the use of these new vaccines within an existing BCG vaccination programme.

WHO working group on standardisation and control of acellular pertussis vaccines--report of a meeting held on 16-17 March 2006, St. Albans, United Kingdom.

This report reflects the discussion and conclusions of a WHO group of experts from national regulatory authorities, national control laboratories, vaccine industry and other relevant institutions involved in standardisation and control of acellular pertussis vaccines, held on 16-17 March 2006, in St. Albans, UK. Following previous discussions (Bethesda, 2000; Ferney-Voltaire, 2003; Geneva, 2005) and collection of relevant data for quality control, on the one hand, and clinical evaluation of acellular pertussis vaccines, on the other, this meeting was intended to review the scientific basis for the revision of WHO guidelines adopted in 1996 [Guidelines for the production and control of the acellular pertussis component of monovalent or combined vaccines. In: WHO Expert Committee on Biological Standardisation. Forty-seventh report. Geneva, World Health Organisation, 1998 (WHO Technical Report Series, No. 878), Annex 2]. The discussion on animal protection models, immunogenicity and toxicity testing was focused on three main aspects: value of the assay for the purpose of licensing and/or lot release; validity criteria and potential optimisation of the assays. The group agreed that establishment of JNIH-3 as a potential International Standard (IS) for modified intra-cerebral challenge assay should be under consideration. It was suggested that the inclusion of a reference vaccine, such as JNIH-3 in the intra-nasal challenge model could improve the standardisation of this assay. It was proposed that the development of stable reference vaccines for immunogenicity testing should be encouraged. Further collection of the data from the countries with established lot release of acellular pertussis vaccines will be undertaken to prepare a solid basis for recommendations on toxicity tests. In the context of recommendations for clinical assessment of new vaccines, the group emphasised the importance of comparability studies with antigens that have already undergone efficacy trials in the past. The outline for the section on clinical evaluation of acellular pertussis vaccines was presented and after the consultation further additions were made. Post-marketing surveillance was recognised as an important part of overall vaccine evaluation and a unique opportunity to understand vaccine performance in the population and to establish a link with quality control.

Establishment of European Pharmacopoeia (Ph. Eur.) Biological Reference Preparations (BRP) batch 2 for rDNA hepatitis B vaccine (method A and B).

A collaborative study was initiated by the European Directorate for the Quality of Medicines (EDQM), to assign a potency value for candidate batch 2 of European Pharmacopoeia (Ph. Eur.) Biological Reference Preparation (BRP) for Hepatitis B (rDNA) antigen in vitro assays, for both method A and method B by calibrating them against the Ph. Eur. BRPs, batch 1 for methods A and B respectively. The study was prompted by the observation that the first batch of BRP for method B appeared to have lost potency over time. BRP 1 for method A showed no loss in potency, however stocks of the material were nearing depletion. Eleven laboratories participated in the study and all reported results. Participants performed 3 independent assays using both method A and method B. Method A was used to assess BRPs for method A and method B was used to assess BRPs for method B. Since BRP 1B was suspected to have lost potency, an additional sample was included in the method B test in an attempt to clarify the situation. BRP 1B was also assayed in method A against BRP 1A in the hope of also attaining further information by comparing the results from this study to those obtained in the original study to establish the first batch of BRP [1]. Although it was not the primary aim of this study to correlate in vitro potency with the immunogenicity assay in mice, a number of interested parties also performed the mouse in vivo assay to obtain data on the behaviour of the candidate BRPs in this assay. For method A, potency estimates were satisfactory in terms of repeatability and reproducibility. The candidate material was therefore assigned a value of 16.6 micrograms/ml. For method B, it appeared that the observation of reduced in vitro potency of BRP1 was confirmed. Despite the attempt to clarify the situation with additional studies, it was not possible to assign a potency value with the results obtained. A small-scale collaborative study will be organised to determine an appropriate value for the candidate BRP for method B. The results from the in vivo study while highly variable showed no evidence of a shift in the in vivo potency for either BRP 1A or BRP 1B. It should be noted that the in vitro method for determination of hepatitis B vaccine potency is under revision due to the discontinuation of the Auszyme kit from Abbott, which is required to perform the current assays. Once an alternative assay has been established, the suitability of the reference preparations or establishment of new reference preparations will be required. The candidate material for method A BRP was adopted by the European Pharmacopoeia Commission at its session in November 2003, as the European Pharmacopoeia Hepatitis B vaccine (rDNA) method A, batch 2.

ICH guidelines and PhEur monographs on derivation and characterisation of cell substrates used for production of biotechnological/biological products. International Conference on Harmonisation.

This presentation gives an overview of the guidance which is available in the EU as it would be applicable to licensing requirements for influenza vaccines produced on banked cells. Whereas ensuring compliance of cell banks would be relatively straightforward, ensuring compliance of new virus seeds (and possibly harvests) with requirements concerning adventitious viral contamination needs further evaluation.

Sensitivity to avian sensitin of tuberculin reactors in Belgium.

It was proposed that a study should be made on the specificity of the reactions of 1068 subjects reacting "weakly to moderately" to an intradermal test with 2 units of PPD RT23; 43% were classified as "positives" (greater than or equal to 10 mm) and Palmer type IV indurations or merely erythema were seen in 81%. Three months later, the same people were retested, this time with 2 units of PPD RT23 and, simultaneously, with 0.1 mcg of avian sensitin: 23% of all reactors (13% of all "positives", but none with a Palmer type I of II induration) had completely lost their sensitivity to RT23. Of the 1068 original reactors, 87% reacted to avian sensitin and 69% did so with a reaction greater than or equal to to human RT23. According to the results of this double test, and depending on the strictness of the comparative criterion, 69% to 84% of the original reactors (65% to 78% of the "positives") would be classified as non-specifically infected. There was a high degree of agreement between an induration greater than or equal to 10 mm to PPD RT23 in the second test and classification as specific infection, based on a comparative criterion.

Molecular sizing of individual polysaccharides in polyvalent pneumococcal and meningococcal vaccines by column chromatography and immunoelectrophoresis.

We determined the molecular size of meningococcal and pneumococcal polysaccharides in final vaccines, using a combination of column chromatography and simple rocket immunoelectrophoresis. We found a good correlation between the distribution coefficients obtained with UV monitoring or ELISA and immunoelectrophoresis.

The potency of bovine PPD tuberculins in guinea-pigs and in tuberculous cattle.

Potency differences between bovine purified protein derivative tuberculin preparations produced in two different centres and also between preparations produced within these centres, were detected in tuberculous cattle and correlated with potency differences in guinea-pigs. Although assays in groups of guinea-pigs sensitized with either killed Mycobacterium bovis or live BCG identified the weak batches and listed the tuberculins in the same order of potency as the cattle assays, there were nevertheless significant differences between potency estimates according to the mode of sensitization and the preparations compared. The implications for the standardization of tuberculin preparation in general are discussed.