opamtistomig

Opamtistomig is a potential first-in-class tetravalent bispecific antibody that simultaneously targets **PD-L1** (programmed death-ligand 1) and **4-1BB** (CD137), a co-stimulatory receptor. Developed by Nanjing Leads Biolabs using their proprietary X-Body™ bispecific platform, it features a 2:2 format with two binding domains each for PD-L1 and 4-1BB, with an optimized affinity ratio. This dual mechanism blocks PD-1/PD-L1-mediated immune suppression while selectively enhancing T-cell activation through 4-1BB agonism, potentially converting immunologically "cold tumors" into "hot tumors" and overcoming resistance to immunotherapy. The drug has demonstrated promising efficacy and favorable safety in patients with extrapulmonary neuroendocrine carcinoma (EP-NEC), both as monotherapy and in combination with chemotherapy. It is the first 4-1BB-targeting bispecific antibody globally to reach the single-arm pivotal trial stage as a monotherapy and holds promise to become the first approved treatment specifically for EP-NEC. Opamtistomig received Breakthrough Therapy Designation from China's NMPA in October 2024 and Orphan Drug Designation from the U.S. FDA for neuroendocrine carcinoma in November 2024.

Brand names

Opamtistomig

Other names

anti-PD-L1/4-1BB bispecific antibody