Drug intelligence / Profile preview

STA551

Development stage
Phase 1
Lead developer
Chugai Pharmaceutical
Modality
Monoclonal Antibodies → Antibody-Based Therapeutics
Administration
Intravenous
01

Overview

STA551 is a humanized monoclonal antibody engineered to selectively activate **CD137** (also known as **4-1BB**, a member of the tumor necrosis factor receptor superfamily) only in the presence of elevated extracellular adenosine triphosphate (ATP), a distinguishing feature of the tumor microenvironment in solid tumors. This "switch" mechanism translates into tumor-selective immune activation and avoids systemic immune activation, aiming to minimize off-tumor toxicity. STA551 has demonstrated potent and broad antitumor efficacy in both murine and human tumor models, maintaining a wide therapeutic window and tolerability at high doses in preclinical studies. It is currently in phase I clinical trials as both monotherapy and in combination with atezolizumab for solid tumors. STA551 is developed using Chugai's proprietary Switch-Ig technology[1][2][3][6][8][9].

Other names
Anti-CD137 agonistic Switch antibodyAnti-CD-137 agonistic Switch antibodyAnti-CD 137 agonistic Switch antibodyCD137 agonist switch antibodyCD-137 agonist switch antibodyCD 137 agonist switch antibody
02

Targets

TNFRSF9 (CD137 extracellular domain)

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