The Target Product Profile (TPP) is first drafted at stage A. The TPP lists key characteristics of the vaccine candidate and evolves as the project progresses. A standard TPP specifies the primary indication (for example, prevention of TB disease), the target population (for example, adolescents and adults), a description of the active drug substance (for example, a live attenuated recombinant BCG that expresses new antigens), the drug product (with additional excipients), and the general characteristics of the vaccine candidate. Additional information includes presentation (liquid, lyophilized), dose, route and schedule and manufacturing aspects (for example, number of doses per campaign, and affordability). Information related to clinical aspects will include: safety and reactogenicity, immunogenicity (immune response, mechanism of protection) and efficacy (prevention of disease, speed of onset of immunity), the number of administrations and schedule (multiple, time between doses), the route of administration, durability of protection (lifetime or time-limited), and whether co-administration with other vaccines (and potential interference) is anticipated. The safety, immunogenicity and efficacy of the vaccine candidate will be documented in animals first, then in humans.

Where possible, the targeted countries and an estimate of the market potential are included, as these might have an influence on the design of the vaccine and its geographic development.

At this initial stage of the TPP, the vaccine candidates are in construction with limited characterisation and supporting data. Still, it is recommended to set targets and specify how information will be obtained, for example, a specific type of study for safety or efficacy. Often, the TPP contains a column of minimal criteria that must be met, and another column of criteria that are desirable.

There are multiple sources for general guidance on preparation of a TPP, which include Lee and Burke, Vaccine2010, FDA Guidance and UK MRC guidance. For guidance with more specificity for TB vaccines it is suggested to review the package insert for commercial BCG (BCG SSI, BCG SII and BCG Tice) and the WHO PPC for New TB Vaccines.

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The integrated Product Development Plan (PDP) is introduced at Stage B and is used in conjunction with the TPP. The PDP is a living document that contains an overview and history of the vaccine and describes the main activities per function, and how they integrate. As such, the PDP defines the roadmap to reaching a product with the characteristics described in the TPP. The initial PDP should list activities leading up to, at least, the end of the First-in-Human (FIH) or Phase 1 clinical study. The recommendation is to organise the PDP per function (PM, product characteristion, process, pre-clinical and regulatory), and ensure that they are integrated and connected. The PDP contains a planning tool such as a Gantt chart which specifies tasks, timescales and their inter-dependencies. It also contains a budget and the required capacity (human resources, internal and external expertise). Importantly the PDP contains an assessment of risks, mitigations and a gap analysis. Once the pieces of the development plan are integrated and connected, milestones, decision points and a critical path can be established.

The TPP and PDP are updated as the project prepares the planning for clinical Phase 1. The PDP should include new information from the characterisation and process activities and data generated in pre-clinical studies. It should also include details of the preparation for the Phase 1, First-In-Human (FIH) study, with its design (population, doses, schedule etc.) or a synopsis of the protocol. It should also include other Phase 1 studies, if planned. The Gantt chart and budget are updated.

The TPP and the PDP are updated as operations for FIH are prepared. The TPP contains the description of the vaccines that will enter into Phase 1. The PDP includes new information from characterisation and process development activities, as well as data from animal studies for safety, immunogenicity and efficacy. It also contains detailed activities for Chemistry, Manufacturing and Controls (CMC), regulatory and clinical aspects and how they integrate, for preparation of Phase 1. The PDP assumes success of Phase 1, and therefore expands on a description of activities in each function up to end of Phase(s) 2, together with revised analysis of resources needed, risks and mitigations and an updated Gantt chart and budget. Moreover, the PDP now integrates activities related to market assessment and ideally a market analysis, the identification of targeted countries, and access strategy.

The TPP and PDP are updated and include data on safety and immunogenicity from Phase 1. While most Phase 1 studies are performed in a single clinical site, Phase 2 studies are multi-centric, and often involve multiple countries. As clinical development progresses, the need for additional resources in clinical and regulatory aspects increases, and coordination is more complex. The PDP further details the strategy related to the Phase 2 programme, and, if needed, a new GMP production for clinical trial material. The PDP anticipates the need for proof-of-concept efficacy study (Phase 2b) and describes its design, overall operations and resources needed, and regulatory strategy. The Gantt chart and budget are updated.

As Phase 2a studies are completed and a proof-of-concept Phase 2a is contemplated, the TPP is updated for the characteristics of the product, which should be final at this stage, for the dose, route and safety profile. The PDP now includes data from Phase 2a and is updated with details on the operations for Phase 2b. There will need to be consideration of and planning for the large costs of a Phase 2b trial, which may require the involvement of multiple funding partners. The PDP contains a revised need for resources, Gantt chart, budget and risk management plan.

Efficacy data are available from the Phase 2b and the TPP is updated accordingly for efficacy and more safety and immunogenicity data. Similarly, the updated PDP contains summaries of data collected to date, including from Phase 2b. The PDP describes and integrates the main activities in process development leading to lot consistency, and presents the design of the Phase 3 and its operations, regulatory aspects (anticipating registration) and marketing (anticipating implementation). It includes a revised Gantt chart and budget. The substantial cost of a large Phase 3 efficacy study is a particular challenge for a TB vaccine since there are limited sources and amounts of funding available. It is likely that a consortium-based approach will be needed in order to raise sufficient funds and the establishment and management of this consortium will need to be specifically resourced.

Efficacy is evaluated at this stage, leading to a major decision at Gate H to progress to registration. The PDP is focusing on the performance of Phase 3 and regulatory, anticipating that efficacy and safety data will meet TPP attributes and support the related product information in the leaflet. Potential additional indications should be sought in subsequent Phase 4 clinical studies.

The PDP is updated to include activities of each functional area to prepare the market authorisation application, obtain approval and prepare for launch.

The PDP is updated to include activities of each functional area to launch and implement vaccination programmes.