Welcome to The Nonlinear Library, where we use Text-to-Speech software to convert the best writing from the Rationalist and EA communities into audio. This is: Priority review vouchers for tropical diseases: Impact, distribution, effectiveness, and potential improvements, published by Rethink Priorities on January 5, 2024 on The Effective Altruism Forum.
Suggested citation: Gosnell, G., Hu, J., Braid, E., & Hird, T. 2023. Priority review vouchers for tropical diseases: Impact, distribution, effectiveness, and potential improvements. Rethink Priorities. https://rethinkpriorities.org/publications/priority-review-vouchers.
Funding statement: We thank Open Philanthropy for commissioning and funding this research report. The views expressed herein are not necessarily endorsed by Open Philanthropy.
Editorial note
The report evaluates the value and effectiveness of the United States' Tropical Disease Priority Review Voucher Program, which was initiated in 2007 to incentivize research and development for medical products targeting neglected tropical diseases. (While PRVs have since been legislated for purposes, we focus our attention on this application.) Specifically, we describe some of the program's history to date (e.g., past issuances, voucher sales/use dynamics, and evidence of gaming), the usage extent of PRV-awarded medical products, academic and anecdotal evidence of the program's incentive effect, and ways in which we think the program could be improved.
We have tried to flag major sources of uncertainty in the report and are open to revising our views as more information becomes available. While preparing this report for publication, we learned that Valneva was awarded a PRV for developing the first Chikungunya vaccine in November 2023 (Dunleavy, 2023), but we did not incorporate this information in the report or associated spreadsheets.
We are grateful for the invaluable input of our interviewees. Please note that our interviewees spoke with us in a personal capacity and not on behalf of their respective organizations.
Executive summary
We catalog information about the 13 issuances of Priority Review Vouchers (PRV) under the United States' Tropical Disease PRV Program and, for the seven cases with sufficient data, attempt to estimate the number of treatment courses per 1,000 relevant disease cases, or "use rate." Among the seven products with use rate estimates, we find three with high use rates (>100 courses per 1,000 cases), two have medium use rates (10-100), and two have low use rates (<10). We also find that while all high-use-rate products have been on the market for >10 years, not all products marketed for that long achieve high use rates, and find diverse outcomes in use-rate trajectories, including sharp discontinuities and both upward and downward trends.
Given that PRV recipients can either use or sell their voucher, we also explore the dynamics of how the PRVs' value is distributed among different types of players in the industry. We find that PRV sales proceeds go toward repayment for shareholders of small pharmaceutical companies or toward (promises of) further drug development for neglected tropical diseases. Large pharmaceutical companies that receive PRV awards tend to retain or use the voucher for faster FDA review of a profitable drug in their pipelines.
Additionally, we review four academic studies that attempt to quantify the effectiveness of PRVs at inducing medical innovations for neglected tropical diseases. Based on their findings and our assessment of study quality, we think it is unlikely that the TD PRV Program had a large, consistent effect on R&D for tropical diseases, but that the results are potentially consistent with a small marginal effect. Additionally, there is historic anecdotal evidence of "gaming the system" - seeking a voucher for a drug that has already been developed and marketed outside of the US - though we think it is unlikely to continue to be an issue going forward given t...

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