iii) Classification of product candidates into archetypes

As a starting point, we used the initial archetypes and the descriptions of each archetype from P2I.v1 ( Table 1). In order to further “operationalize” each archetype—i.e., to make it easier for the research team to make decisions about how to classify each candidate—we worked with technical experts to further define each archetype. Table 3 shows the original archetype descriptions from P2I v.1, our additional definitions, and examples of candidate classifications.

As shown in Table 3, product candidates were classified into six broad archetypes—repurposed drugs, NCEs, vaccines, biologics, diagnostics, and “other products” (which refers to vector control products). Repurposed drugs, NCEs, and biologics were further sub-classified into simple versus complex; vaccines into simple, complex, or unprecedented; and diagnostics into assay development versus simple technical platform development. For candidates in the pipeline that were contraceptives, microbicides, or MPTs, these were classified according to the constituent drug (e.g., microbicides in the pipeline were classified as repurposed drugs, NCEs, or biologics). If there was more than one active drug ingredient in the MPT, the candidate was classified according to the most complicated component. We did not consider if the polymer or technology itself was innovative in itself as this went beyond the scope of our costing framework.

The classification of candidates was made by different members of the research team, based on their expertise (repurposed drugs, NCEs, and biologics: KS, KC; diagnostics: BR; vaccines: SP, LD, TS; other products: VC). The classification was based on a combination of (a) technical expertise of the researchers, (b) academic literature, (c) relevant publicly available product databases (e.g., for classifying drugs, ChemBL and chemspider), (d) information from international clinical trials registries, including the WHO International Clinical Trials Registry Platform, (e) websites of PDPs, e.g. the Medicines for Malaria Venture website, (e) patent databases, and (f) relevant reports and news releases from bilateral and multilateral funding agencies, companies, PDPs, other product developers, and non-government organizations. In assigning each candidate product to an archetype, we documented any relevant source material that guided the classification (e.g., a published research article on the candidate’s mechanism of action).

Classification of candidate diagnostics into archetypes was conducted by a technical expert in diagnostics R&D (BR). Using the Policy Cures Research list of candidates, these were further classified into six more specific development phases, as required by P2I v.2: concept; feasibility; early development; late development; validation; and commercialization. Table 4 summarizes what these phases mean and how they compare with two other classification systems for technology readiness (the Technology Readiness Level (TRL) and Manufacturing Readiness Level (MRL), developed by the United States Department of Defense). When it came to inputting candidates into the adapted P2I cost model (as shown in Table 2), diagnostic candidates at the concept phase were placed in the category “concept and research”; those in the feasibility stage were placed in “feasibility and planning”; those in either early or late development were placed in “design and development”; those in validation were placed in “clinical validation and launch readiness”; and those in the commercialization phase were excluded from the cost modelling.

Abbreviations: TRL, Technology Readiness Level; MRL, Manufacturing Readiness Level; MRD, Market Requirements Document; PRD, Product Requirements Document; TPP, Target Product Profile