High attrition and failures rates in pharmaceutical and biotechnological drug development require a paradigm change towards more physiological human cell-based assays at an early time point in the process. The central idea of this proposal is to develop a versatile and reconfigurable pharmaceutical screening technology platform that relies on organotypic three-dimensional spherical microtissues. This platform will accommodate different types of human microtissues (tumor, brain, liver, heart etc.) and feature microfluidic interconnection between these tissues, thus mimicking the physiological context and conditions in a human body. Dosage of components or candidate drugs to, e.g., liver tissue will lead to the generation of metabolic products in the respective tissue compartment. These products then can be routed via the microfluidics to, e.g., connective tissue to assess the efficacy of the candidate drug and related adverse toxicological effects on the target tissue and functionally related tissues. This way, functional connectivity in a real body can be mimicked at the desired level of complexity, and the effects of drugs can be comprehensively assessed.