Nanobody-drug conjugates to deliver drugs into target cells

In current medical practice, each day many patients receive drugs for a variety of diseases. However, a recurrent challenge is the non-specific nature of many drugs. This often leads to well-known adverse effects such as nausea, hair loss, compromised immune function, abdominal pain, diarrhea, vomiting, and weight loss. In this context, antibody-drug conjugates (ADCs) have been developed to target drugs specifically to target cells. Although ADCs are successfully used in the clinic, they still come with severe and dose-limiting side effects. Recently, the concept of nanobody-drug conjugates (NDCs) emerged as a promising approach to achieve targeted drug delivery. NDCs hold the potential to mediate the interaction with the target cells to direct therapeutic agents specifically to designated cells. These NDCs consist of three essential components: (1) the nanobody serving as a carrier for drug delivery specifically to the target site, (2) the drug itself, effective upon successful nanobody-mediated delivery, and (3) the linker that connects the nanobody and the drug, enabling controlled drug release upon reaching the target site. This thesis focused on the development of NDCs for intracellular drug delivery. More specifically, we investigated the effect of the nanobody format on internalization kinetics and NDC cross-reactivity, the impact of internalization kinetics on intracellular drug delivery using NDCs, and the use of different linkers and drugs that can be employed in NDCs.