Drawing on data from the World Health Organization International Clinical Trials Registry Platform and employing a difference-in-difference-in-differences estimation approach, our study builds on the existing literature and shows that the PRV does not show significant effect at generating trial activity.

The policy does not seem to have triggered an increase in R&D for the intended diseases following its implementation, not even in late-phase trials, which are generally common in the neglected diseases era when repurposing drug indications or developing new treatment regimens. Accordingly, the benefit of the voucher, whether used or sold, does not appear a sufficiently strong incentive for pharmaceutical companies to embark on risky R&D.

Three main policy recommendations arise from our study. First, the PRV should not be seen as a stand-alone solution but as a complementary solution alongside other incentivizing mechanisms when tackling diseases of the world’s poorest populations. Second, if the PRV program is to continue, the PRV should reward products that bring novelty and not reward products that are already licensed outside the US. Doing so would restrict the number of vouchers awarded and slow down their ongoing market depreciation. Lastly, the PRV should require product sponsors to submit an access plan for PRV-awarded products.