Solving the mystery of Vifor’s new voucher

Today Vifor Pharma said it had bought a priority review voucher. What it did not say, however, is from whom it bought it, how much it paid, or the use to which the voucher is to be put. Fortunately educated guesses can be made regarding all these unknowns. The table below reveals that 21 unused vouchers are thought to be in existence, and might thus have been sold to Vifor. As to price, the vouchers that changed hands last year went for about $100m – Vifor presumably would have paid around the same amount. When it comes to the project for which Vifor’s voucher might be used, the obvious candidate is vadadustat, in US phase III trials for the treatment of anaemia due to chronic kidney disease. Notably, one of the main candidates for use of the priority review voucher Astrazeneca bought from Sobi last year is the similar project roxadustat – though when Fibrogen, Astra’s partner, announced the filing it did not mention priority review. Perhaps this is a chance for Vifor, and its US partners Akebia Therapeutics and Otsuka, to steal a march on the competition.