Have PRVs failed? Some of the recent articles about the FDA’s Office of Orphan Drug Products push for drug companies to examine existing medicines for potential benefits for rare disorders would like you to think so.

 

Guess what? They’re wrong.

 

Here are some of the hard facts. The FDA Priority Review Voucher (PRV) program was signed into law on September 27, 2007, as part of the U.S. Food and Drug Administration Amendments Act of 2007 (FDAAA). It is true that only one PRV has been issued so far, to Novartis upon FDA approval of their anti-malarial treatment Coartem. But it was awarded on April 2009, just five months after the FDA issued the Draft Guidance for Industry (October 2008) that created the program – lightening speed in the world of policy-making and implementation. The PRV program is moving forward very quickly, but long product development timelines dictate that it will take time to blossom.

 

Pipelines for neglected disease drugs and vaccines are slim, and the PRV incentive is meant to encourage companies to pick that “low-hanging fruit” and make the “go” decision to pursue a research and development (R&D) program on promising compounds and targets. Yet, as anyone who knows the drug and vaccine development process understands, it can take 6-7 years to complete the discovery process to identify a potential drug candidate, then another 8-9 years to develop and test it for human use. Grabowski, Ridley, and Moe, the Duke University professors that conceived the PRV idea, make the point of how this translates for the PRV program in their 2008 paper, “given that R&D is high-cost, high-risk, and can stretch over long time periods, there must be a credible expectation that the PRV will in fact speed drug approval. Many companies might wait to see if this is the case before initiating new R&D programs targeting neglected diseases—and the markets for vouchers could be slow to develop.”

 

Companies are interested in seeing, in practice, exactly how much time is saved when using a PRV to accelerate the review of an application. If they are able to quantify the time saved, which is estimated at 4-10 months, they can plan their manufacturing, marketing, and distribution strategies to gain earlier market entry, and therefore gain the first-mover advantage on which a bulk of the PRV value has been calculated. For this reason, awarding a PRV to Novartis early is an important test case to help establish a value around the PRV so that companies can begin to properly integrate these estimates into their business strategies, which often determine which research projects achieve priority status. It is also important that some critical changes to the FDA guidance be made that would clarify the rules around the use of the PRV and increase its value as an incentive.

 

We at BIO Ventures for Global Health support the PRV program and are working to ensure that it is implemented as it was intended. The economists that authored the original idea knew it would take several years to see the program come into full bloom, and we are still in the nascent stages. If, in 5-10 years, the monetary value of the PRV has not measured up to current estimates, and no more drugs and vaccines are in the pipelines for neglected diseases than there otherwise would be, we may call the program a failure. For now, let’s continue to encourage companies to take advantage of this incentive, and encourage the FDA to continue to support implemenation of rapid regulatory review so that the PRV may show its true colors.