GlaxoSmithKline (GSK) has said that all rights to ispinesib and SB-743921, each novel inhibitors of kinesin spindle protein (KSP), will revert to Cytokinetics, on agreed terms. The collaboration between Cytokinetics and GSK will continue, and is expected to be focused on the development by GSK of GSK-923295, an inhibitor of centromere-associated protein-E (CENP-E).
Cytokinetics will proceed, independent of GSK, with the further development of ispinesib and SB-743921 subject to agreed terms. GSK-923295, now in a Phase I clinical trial in advanced cancers, is being developed under the strategic alliance with GSK.
Robert Blum, president and CEO of Cytokinetics, said: While we are disappointed in this outcome, we understand GSK’s business decision. We are encouraged by the safety and tolerability of each of ispinesib and SB-743921 as well as the amplified activity observed with the more dose-dense scheduling of these novel drug candidates.
We are committed to advancing these two drug candidates through to the end of Phase I and will then evaluate the next steps for ispinesib and SB-743921 in context of the results, required funding and other partnering possibilities.