Delivering therapy to target: improving the odds for successful drug development.

The direct delivery of drugs and other agents into tissue (in contrast to systemic administration) has been used in clinical trials for brain cancer, neurodegenerative diseases and peripheral tumors. However, continuing evidence suggests that clinical efficacy depends on adequate delivery to a target. Inadequate delivery may have doomed otherwise effective drugs, through failure to distinguish drug inefficacy from poor distribution at the target. Conventional pretreatment clinical images of the patient fail to reveal the complexity and diversity of drug transport pathways in tissue. We discuss the richness of these pathways and argue that development and patient treatment can be sped up and improved by: using quantitative as well as 'real-time' imaging; customized simulations using data from that imaging; and device designs that optimize the drug-device combination.