h11B6

h11B6 is a humanized immunoglobulin G1 (IgG1) monoclonal antibody that specifically targets human kallikrein-2 (hK2), a serine protease highly expressed in prostate tissue and regulated by androgen receptor activity. The antibody binds to the catalytic cleft of active hK2 and internalizes into prostate cancer cells. It serves as the targeting component in radioimmunoconjugates such as actinium Ac 225-DOTA-h11B6 (JNJ-69086420), where it is conjugated with a chelator (DOTA) and labeled with alpha-emitting radioisotopes like actinium-225 for targeted alpha therapy or indium-111 for imaging. These constructs are being developed primarily for metastatic castration-resistant prostate cancer (mCRPC) and advanced prostate carcinoma. Preclinical studies have shown selective tumor uptake with minimal normal tissue accumulation, sparing organs such as salivary glands[1][3][5][8].