Competitive diffusion of new prescription drugs: The role of pharmaceutical marketing investment

• Marketing efforts mainly affect trial rates via external and not via internal influence.
• Pharmaceutical marketing has both informative and persuasive effects on diffusion.
• Reallocating the marketing budget affects the speed of diffusion and maturity stage.

We investigate the impact of marketing interventions on the diffusion of new products in a competitive setting. We develop a family of trial–repeat diffusion models to identify the longitudinal effects of marketing efforts, and complement this with a cross-sectional analysis to identify the between-drug effects. We believe that we are the first to consider both longitudinal and cross-sectional marketing effects in a trial–repeat diffusion context. The models are calibrated on 34 drugs in three therapeutic categories using monthly data. Our longitudinal analyses demonstrate that the trial rate responds positively to increases in own marketing expenditures but is affected negatively by competitors' expenditures. We show how these within-drug analyses provide opportunities for accelerating the diffusion process by reallocating marketing expenditures over time. The cross-sectional analyses demonstrate that pharmaceutical marketing has both an informative and a persuasive influence on the diffusion of new drugs. We find that direct-to-consumer advertising does not affect the trial nor repeat rates during the first months after introduction. We illustrate the managerial relevance of our results and find that a reallocation of marketing budgets does not alter the saturation level, but can help in attaining this level faster. We show that this has a great effect on sales, market share and ROI.