GBR-900 is a humanized monoclonal antibody targeting Tropomyosin Receptor Kinase A (TrkA/NTRK1). TrkA is the high-affinity receptor for Nerve Growth Factor (NGF), widely expressed on sensory neurons of the dorsal root ganglia and basal forebrain cholinergic neurons in the central nervous system. The NGF/TrkA signaling pathway plays a pivotal role in pain transmission and the initiation and maintenance of chronic pain, particularly inflammatory and neuropathic pain. GBR-900 specifically binds to TrkA, blocking the interaction between NGF and its receptor, thereby inhibiting downstream pain signaling. Compared to antibodies directly targeting NGF, GBR-900 has demonstrated comparable analgesic efficacy in preclinical studies but with a superior safety profile (e.g., no dose-limiting toxicity). It is primarily investigated for the treatment of chronic pain, such as osteoarthritis pain.