Rational Design of Chemically Controlled Antibodies and Protein Therapeutics

Protein-based therapeutics, suchas monoclonal antibodiesand cytokines,are important therapies for various pathophysiological conditionssuch as oncology, autoimmune disorders, and viral infections. However,the wide application of such protein therapeutics is often hinderedby dose-limiting toxicities and adverse effects, namely, cytokinestorm syndrome, organ failure, and others. Therefore, spatiotemporalcontrol of the activities of these proteins is crucial to furtherexpand their application. Here, we report the design and applicationof small-molecule-controlled switchable protein therapeutics by takingadvantage of a previously engineered OFF-switch system. We used theRosetta modeling suite to computationally optimize the affinity betweenB-cell lymphoma 2 (Bcl-2) protein and a previously developed computationallydesigned protein partner (LD3) to obtain a fast and efficient heterodimerdisruption upon the addition of a competing drug (Venetoclax). Theincorporation of the engineered OFF-switch system into anti-CTLA4,anti-HER2 antibodies, or an Fc-fused IL-15 cytokine demonstrated anefficient disruption in vitro, as well as fast clearance in vivo uponthe addition of the competing drug Venetoclax. These results providea proof-of-concept for the rational design of controllable biologicsby introducing a drug-induced OFF-switch into existing protein-basedtherapeutics.