Challenges and Perspectives of Tumor-targeted Systems

Abstract

Since the first nano-drug (Doxil®, a kind of liposome formulation) was approved by the Food and Drug Administration (FDA), both the scale of clinical translation and the research depth of the basic theory of nanomedicine for tumor treatments have been greatly improved [1]. More than 800 clinical trials of nanomaterials have been undergoing evaluation [2]. Delivering cargos by nanocarriers demonstrates superior advantages over free drugs including controlled pharmacokinetics, targeted tissue distribution, limited adverse side effects, and inspiring diagnostic and therapeutic efficacy [3]. However, due to superficial knowledge of cancer, applications of clinical nanomedicines are still “in prison” due to the drug resistance, tumor relapse, and failure to elicit the enhanced anti-tumor efficacy [4]. Up to now, only about 170 nanomedicines and nano-imaging agents were approved for tumor treatments by the FDA and European Medicine Agency (EMA), most of which are organic nanomaterials such as liposomal and polymeric systems [5, 6]. Although inorganic nanocarriers and other novel nanomaterials have been developed, only a few of them were investigated in clinical trials and even fewer were approved by the FDA [7]. As the old saying goes, without a chill, there is no sweet plum blossom. For the development of nanomaterials in tumor diagnosis and therapy, more efforts are needed.