Exelixis previously said that XL784 failed to meet its primary endpoint in a Phase II trial. Although the data in one subgroup were encouraging, Exelixis believes that the exciting data being generated by other compounds to which GlaxoSmithKline (GSK) has an option under its collaboration agreement with Exelixis made it unlikely that GSK would use one of its one or two remaining options to choose XL784.
As a result of GSK’s decision, Exelixis has the right to develop and commercialize XL784 either independently or in collaboration with third parties, subject to payment to GSK of a 3% royalty on sales of any products incorporating the compound.