There was a lot of excitement surrounding the development of small molecule PARP inhibitors as synthetic lethal agents targeting BRCA-mutant cancers, then disappointment about the results of a phase III trial that failed to show any benefit and now the finding that the first generation clinical PARP inhibitor Iniparib maybe wasn't that good at inhibiting PARP after all.  The linked article provides a terrific overview of where improvements in the process of drug development need to be made, starting with better preclinical research.