Malaria drug Coartem. Credit: Novartis

The first company to deploy a priority review voucher (PRV) received a complete response letter from the US Food and Drug Administration (FDA) provoking criticisms that the scheme has failed. The scheme was established in 2008 as an incentive for developers of drugs for neglected tropical diseases. Novartis of Basel recently used the only PRV issued so far—granted for the approval of the antimalarial drug Coartem (artemether/lumefantrine) in 2009—to have a 'priority' review of their supplemental biologics license application (sBLA) to the FDA for Ilaris (canakinumab). “We decided to utilize our PRV for ACZ885 (canakinumab) in gouty arthritis because of the significant unmet need that exists despite standard treatment options,” says Eric Althoff, head of global media relations. Unfortunately, Novartis received a complete response letter from the FDA requesting additional clinical data to evaluate the benefit-risk profile for use of Ilaris in refractory patients. As Novartis used their PRV (which cost an additional fee of $5,280,000 on top of the sBLA fee) but did not achieve approval of the supplementary indication for Ilaris, industry observers have been quick to suggest that use of this first PRV has been a failure. This is because the potential value of the PRV has been predicted based on additional sales revenue that a company would theoretically receive if approval was achieved at an earlier date. “Some studies have estimated the value of the voucher to be more than $300 million, others have estimated that it would provide a company with approximately four additional months of peak sales of a product,” says Nick Cammack, head of GlaxoSmithKline's Tres Cantos Medicines Development Campus in Spain. However, as use of the first PRV has not resulted in increased sales revenues in the short term, many are questioning the voucher's value as an incentive to develop drugs for neglected tropical diseases. Nevertheless, Tim Wells, CSO of the Medicines Malaria Venture in Geneva, remains optimistic of the voucher's value. “Even if only one in ten of the vouchers were deployed successfully, it would still have a book value of tens of millions of dollars. This is enough to help drive innovative clinical development.” Cammack adds, “As only one PRV has been awarded, we believe it is too early to draw any conclusions on the effectiveness of PRVs as an incentive.”