Interdependency of influential parameters in therapeutic nanomedicine.

INTRODUCTION Current challenges to successful clinical translation of therapeutic nanomedicine have discouraged many stakeholders, including patients. Significant effort has been devoted to uncovering the reasons behind the less-than-expected success, beyond failures or ineffectiveness, of therapeutic nanomedicine products (e.g., cancer nanomedicine). Until we understand and address the factors that limit the safety and efficacy of NPs, both individually and in combination, successful clinical development will lag.Areas covered: This review highlights the critical roles of interdependent factors affecting the safety and therapeutic efficacy of therapeutic NPs for drug delivery applications.Expert opinion: Deep analysis of the current nanomedical literature reveals a history of unanticipated complexity by a wide range of stakeholders including researchers. In the manufacture of nanomedicines themselves, there have been persistent difficulties with reproducibility and batch-to-batch variation. The unanticipated complexity and interdependency of nano-bio parameters has delayed our recognition of important factors affecting the safety and therapeutic efficacy of nanomedicine products. These missteps have had many factors including our lack of understanding of the interdependency of various factors affecting the biological identity and fate of NPs, inappropriate use of techniques to assess/examine safety and efficacy of nanomedicine (e.g., toxicity assays not developed specifically for nanomaterials), and biased interpretation of data. All these issues could raise significant concern regarding the reproducibility - or even the validity - of past publications that in turn formed the basis of many clinical trials of therapeutic nanomedicines. Therefore, the individual and combined effects of previously overlooked factors on the safety and therapeutic efficacy of NPs need to be fully considered in nanomedicine reports and product development.