(3R,4S)-4-(6-Methoxypyridin-3-yl)pyrrolidine-3-carboxylic acid dihydrochloride is a chiral, heterocyclic compound featuring a pyrrolidine-3-carboxylic acid core substituted with a 6-methoxypyridin-3-yl group. It is typically supplied as a dihydrochloride salt to enhance stability and solubility. The compound contains both a carboxylic acid and a secondary amine (in the pyrrolidine ring), making it a versatile building block for medicinal chemistry. This compound is a key chiral intermediate in the synthesis of Rocatinlimab (AMG 451/KHK4083), a first-in-class, anti-OX40 monoclonal antibody being developed for the treatment of moderate-to-severe atopic dermatitis and other inflammatory diseases. While Rocatinlimab itself is a biologic, small molecule intermediates like this are crucial for constructing linker-payload components or for research into related small molecule drug candidates targeting immune pathways. Its specific stereochemistry ((3R,4S)-trans) is critical for its intended biological activity and integration into more complex molecular architectures. As a pharmaceutically relevant intermediate, it is primarily used in research and development settings. Handling requires standard laboratory precautions for fine chemicals, including the use of personal protective equipment due to its salt form and potential irritant properties.