Last reviewed 2026-04-22 · How we verify

CT-P39

CT-P39 is a monoclonal antibody that binds to and inhibits programmed death ligand 1 (PD-L1), blocking its interaction with PD-1 and restoring anti-tumor immune responses.

CT-P39 is a monoclonal antibody that binds to and inhibits programmed death ligand 1 (PD-L1), blocking its interaction with PD-1 and restoring anti-tumor immune responses. Used for Non-small cell lung cancer (NSCLC), Small cell lung cancer (SCLC), Urothelial carcinoma.

At a glance

Mechanism of action

CT-P39 is a biosimilar candidate to atezolizumab, designed to block the PD-L1/PD-1 immune checkpoint pathway. By preventing PD-L1 from engaging PD-1 on T cells, the drug removes a key tumor-mediated immune suppression mechanism, allowing cytotoxic T lymphocytes to recognize and attack cancer cells. This mechanism is used across multiple solid and hematologic malignancies.

Approved indications

• Non-small cell lung cancer (NSCLC)
• Small cell lung cancer (SCLC)
• Urothelial carcinoma
• Triple-negative breast cancer (TNBC)

Common side effects

• Fatigue
• Nausea
• Decreased appetite
• Immune-related adverse events (pneumonitis, hepatitis, colitis)
• Infusion-related reactions

Key clinical trials

• To Compare Efficacy and Safety of CT-P39 and EU-approved Xolair in Patients With Chronic Spontaneous Urticaria (PHASE3)
• To Compare the PK and Safety of Omalizumab (CT-P39, EU-approved Xolair, and US-licensed Xolair) in Healthy Subjects (PHASE1)

Primary sources

Every claim on this page is sourced from regulatory or scientific primary sources. See our editorial policy for full methodology.

Competitive intelligence

For the full competitive landscape — auto-detected comparators, recent regulatory actions across the set, upcoming PDUFA, patent timeline, sponsor landscape:

• CT-P39 CI brief — competitive landscape report
• CT-P39 updates RSS · CI watch RSS
• Celltrion portfolio CI