90% of all preclinical drug candidates fail to make the grade. Now novel methods that employ miniaturised organs could help overcome this healthcare hurdle. Researchers and CROs are testing a range of models – whether grown from stem cells or spit out by 3D bioprinters – to identify toxicities, simulate cancer development and identify responders to expensive therapies. The field of 3D microtissue-based screening is just a decade old, but it clearly is soon going to play a key role when it comes to improving productivity in drug development.