SG2285 is differentiated from SG2000 in that it is a PBD dimer C11-prodrug which is activated by hydrolysis. Its active component, SG2202, is even more potent than SG2000 and the combination of these properties promises a wider therapeutic window. Additionally, the prodrug nature of SG2285 is envisaged to impact significantly on the toxicity profile of this type of molecule. In in vivo studies, SG2285 is tolerated at significantly higher doses compared to SG2000. It also yields complete tumor regression at non-toxic doses in a number of difficult-to-treat xenograft models.