tislelizumab — Drug Monograph

Brand names: Tevimbra

Drug class: Checkpoint Inhibitor

Mechanism of Action

Tislelizumab is a humanized IgG4 anti-PD-1 monoclonal antibody with an engineered Fc region that minimizes binding to Fcγ receptors (FcγRs) on macrophages, preventing macrophage-mediated antibody-dependent phagocytosis of T cells (known as "trogocytosis" of PD-1). This engineering preserves the functional T cells at the tumor site, potentially maintaining a more durable anti-tumor response. By blocking PD-1 interactions with PD-L1 and PD-L2, tislelizumab restores T-cell receptor signaling and reverses T-cell exhaustion. Enhanced cytotoxic T-lymphocyte activity and reduced Treg-mediated…

FDA Indications

• Unresectable or metastatic esophageal squamous cell carcinoma (ESCC) with disease progression on or after prior platinum-based chemotherapy (approved March 2024; RATIONALE-302 trial)

Common Side Effects

• Fatigue (≥10%)
• Musculoskeletal pain
• Rash
• Decreased appetite
• Hypothyroidism
• Nausea
• Constipation
• Pruritus
• Increased AST/ALT
• Anemia
• Cough

Clinical Pearl

The unique Fc engineering of tislelizumab differentiates it mechanistically from other anti-PD-1 agents by reducing macrophage-mediated T-cell clearance within the tumor microenvironment, which may translate to sustained T-cell effector function. In the RATIONALE-302 trial, tislelizumab demonstrated significantly improved OS vs. chemotherapy in previously treated ESCC (HR 0.70), with particular benefit in PD-L1-high expressors (TAP score ≥10%). PD-L1 tumor area positivity (TAP) scoring was…

Related Therapies & Mechanisms

• Atezolizumab (Tecentriq) — Checkpoint Inhibitor
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• Cemiplimab (Libtayo) — Checkpoint Inhibitor
• Cosibelimab (Unloxcyt) — Checkpoint Inhibitor