F(ab')2-gzk

F(ab')2-gzk is an antibody fragment derivative of the fully human anti‑cocaine monoclonal antibody GNCgzk, engineered as an F(ab')2 format that retains bivalent high‑affinity binding to cocaine while lacking the Fc region. GNCgzk and its F(ab')2 variant bind cocaine in the low‑nanomolar range and act as a peripheral cocaine “sink,” sequestering the drug in the circulation and thereby reducing its distribution to the central nervous system and mitigating cocaine‑induced toxicity, including lethality, ataxia, and seizures in animal overdose models.[1] As an F(ab')2 fragment, F(ab')2-gzk is smaller than full IgG, does not bind Fc receptors or Protein A/G, and is being explored preclinically as an immunopharmacotherapy approach for the treatment of acute cocaine overdose.[1][2][3]