In neurodegenerative diseases (ND), misfolded protein aggregates accumulate in the brain and/or spinal cord; for example, Aβ and tau in Alzheimer’s disease (AD), α-synuclein in Parkinson’s disease (PD), and TDP-43 in amyotrophic lateral sclerosis (ALS). These aggregated proteins are believed to exert their toxicity to host cells including neuron, microglia and astrocyte. Given the hypothesis, a myriad of potential therapeutics including anti-Aβ antibody have been studied. However, most of the attempts have ended up with failure in the past. It’s commonly believed that one of the main obstacles in ND therapeutics development is the blood-brain barrier (BBB), a physiological insulation machinery of the central nervous system (CNS) vascular system.  

To overcome the difficulty, there is a need for technology that penetrates the BBB to efficiently deliver drugs to the CNS. In recent years, researchers have developed some methodologies which confer drugs the potential to penetrate the BBB, such as an antibody against the transferrin receptor 1 (TfR1). For instance, some reports suggest that the antibody shows a potential to pass through the BBB and work as a drug delivery vehicle. 

Such cutting-edge technology is thought to enable the development of novel therapeutics which were not possible due to technical difficulties in the past. As such, many players in the pharmaceutical industry have been trying to apply this technology to develop novel pharmaceutical therapies. However, these technologies are still immature and require significant improvements for clinical implementation in terms of drug delivery efficiency and pharmacokinetics.