Exelixis, Inc. said GlaxoSmithKline (GSK) has decided not to exercise its option to license XL784 for further development and commercialisation. Exelixis previously announced that XL784 failed to meet its primary endpoint in a phase II trial in patients with diabetic nephropathy.

As a result of GSK's decision, Exelixis said it has the right to develop and commercialise XL784 either independently or in collaboration with third parties, subject to payment to GSK of a 3 per cent royalty on sales of any products incorporating the compound.

XL784 is a potent inhibitor of the ADAM-10 and MMP-2 metalloprotease enzymes, targets of significant interest because of their important role in renal fibrosis and impairment. Although the phase II trial in patients with diabetic nephropathy did not meet its primary endpoint, there were encouraging data from the trial. Exelixis believes that the exciting data being generated by other compounds to which 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.

The compound was well tolerated, and the subgroup of patients who were being treated with maximal doses of ACE inhibitors or ARBs did appear to show a substantial benefit from XL784, although this difference did not reach statistical significance. Exelixis itself does not intend to invest further in the development of this drug, but will seek a partner with which to take the compound forward.

XL784 is part of Exelixis' clinical development financing arrangement with Symphony Evolution, Inc.

Exelixis is a development-stage biotechnology company dedicated to the discovery and development of novel small molecule therapeutics for the treatment of cancer and other serious diseases.