While commonly argued that there is a mismatch between drug innovation and disease burden, there is little evidence on the magnitude and direction of such disparities. In this paper we measure inequality in innovation, by comparing R&D activity with population health and GDP data across 493 therapeutic indications to globally measure: (i) drug innovation, (ii) disease burden, and (iii) market size.

We use concentration curves and indices to assess inequality at two levels: (i) broad disease groups; and (ii) disease subcategories for both 1990 and 2010.

For some of top burden disease subcategories (i.e. cardiovascular and circulatory diseases, neoplasms, and musculoskeletal disorders) innovation is disproportionately concentrated in diseases with high burden and larger market size, whereas for others (i.e. mental and behavioural disorders, neonatal disorders, and neglected tropical diseases) innovation is disproportionately concentrated in low burden diseases.

These inequalities persisted over time, suggesting inertia in pharmaceutical R&D in tackling the global health challenges.

Our results highlight the priority disease areas for R&D investment in both developed and developing countries.