toripalimab — Drug Monograph

Brand names: Loqtorzi

Drug class: Checkpoint Inhibitor

Mechanism of Action

Toripalimab is a humanized IgG4κ monoclonal antibody that selectively binds to the PD-1 receptor on T lymphocytes, blocking interactions with its ligands PD-L1 and PD-L2. This prevents PD-1-mediated co-inhibitory signal transduction, reversing T-cell exhaustion characteristic of the EBV-associated immunosuppressive tumor microenvironment of nasopharyngeal carcinoma. Blockade of this checkpoint pathway restores cytotoxic T-cell proliferation and effector function, enhancing immune-mediated tumor lysis. The Fc region is engineered to minimize antibody-dependent cellular cytotoxicity (ADCC)…

FDA Indications

• Recurrent or metastatic nasopharyngeal carcinoma (NPC), first-line in combination with gemcitabine and cisplatin (approved October 2023; JUPITER-02 trial)
• Recurrent or metastatic NPC with disease progression on or after platinum-based chemotherapy, as monotherapy (approved October 2023; POLARIS-02 trial)

Common Side Effects

• Fatigue (≥10%)
• Nausea (combination regimen)
• Decreased appetite
• Constipation
• Hypothyroidism
• Rash
• Anemia (combination regimen)
• Thrombocytopenia (combination regimen)
• Neutropenia (combination regimen)
• Increased AST/ALT
• Peripheral neuropathy (combination regimen)
• Alopecia (combination regimen)

Clinical Pearl

Toripalimab is the first and only PD-1 inhibitor approved specifically for nasopharyngeal carcinoma in the United States, addressing an EBV-driven tumor that disproportionately affects patients of East and Southeast Asian descent. In JUPITER-02, the combination of toripalimab with gemcitabine/cisplatin achieved a median PFS of 11.7 months vs. 8.0 months for placebo plus chemotherapy (HR 0.52), establishing a new first-line standard. Plasma EBV DNA is a useful biomarker for disease monitoring…

Related Therapies & Mechanisms

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