ZymoGenetics has a rich pipeline and, while the IL-21 mAb is an exciting molecule, we believe for our company that other development programmes have a better return on investment profile, said Douglas E. Williams, PhD, chief executive officer of ZymoGenetics. We believe that Novo Nordisk will be able to develop and create value for this asset. Furthermore, we have the option to increase our participation in commercialization of the product, retaining long-term upside potential for our shareholders.

As part of the agreement, ZymoGenetics retains the option to fund a portion of phase 3 clinical development costs in exchange for an increased royalty rate on US sales and US co-promotion rights. If ZymoGenetics exercises the option, it would pay a fixed fee of 10 million dollars together with 15% of the costs of phase 3 clinical trials, and royalties on US sales would increase from single to double digits.