TANGENT study design: a phase III, randomized study of emactuzumab for the treatment of tenosynovial giant cell tumors.

Tenosynovial giant cell tumors (TGCT) are rare, locally aggressive neoplasms causing pain, stiffness, swelling, limited range of motion, and joint degeneration, which can be debilitating. Therapeutic options include surgery or systemic therapy with colony-stimulating factor 1 receptor (CSF-1R) pathway inhibitors. However, many are not amenable to surgery or have high postsurgical recurrence rates. Available systemic therapies require long-term administration and can have burdensome side effects. Emactuzumab is a novel, potent, CSF-1R inhibiting monoclonal antibody with a unique mechanism of action targeting the receptor dimerization interface of the CSF-1R to reduce tumor-associated macrophages and inflammation within the TGCT microenvironment. It is the only short-course, intravenous therapy in development for TGCT. In a phase I study, emactuzumab resulted in robust and durable responses, and a manageable safety profile in patients with TGCT, supporting further research as a treatment option to address unmet need and improve quality of life in patients with TGCT. TANGENT is a randomized, double-blind, global, phase III study (NCT05417789) to investigate the safety and efficacy of intravenous emactuzumab versus placebo in patients with TGCT not amenable to surgery.