Cemiplimab is a PD-1 inhibitor indicated for the treatment of metastatic or locally advanced cutaneous squamous cell carcinoma (CSCC) in patients who are not suitable for curative surgery or radiotherapy. While it activates the immune system to fight tumors, it may also trigger immune-related adverse reactions.

Precautions for Cemiplimab Administration

Immune-Mediated Adverse Reactions

Pneumonitis: The incidence rate is 2.4%, including fatal cases (0.2%). If new or worsening cough, chest pain, or dyspnea occurs, administration must be discontinued immediately and the patient evaluated.

Colitis: The incidence rate is 0.9%, presenting with diarrhea, bloody stools, or abdominal pain. Severe cases require permanent discontinuation of treatment.

Hepatitis: The incidence rate is 2.1%, which may progress to liver failure (0.2%). Monitor for abnormal liver function (e.g., ALT/AST elevation to more than 3 times the normal level).

Endocrine Disorders: These include thyroid dysfunction (6%), adrenal insufficiency (0.4%), and type 1 diabetes (0.7%). Long-term hormone replacement therapy is required.

Management of Infusion Reactions

Approximately 0.2% of patients experience Grade 3 infusion reactions. During the first infusion, closely monitor for symptoms such as chills, fever, and hypotension.

If mild reactions occur, the infusion rate can be slowed down; severe reactions require permanent discontinuation of treatment.

Contraindications in Special Populations

Pregnancy: Animal studies have shown that inhibition of the PD-1 pathway can lead to fetal death. Women of childbearing age must use contraception until 4 months after the last dose.

Lactation: Breastfeeding is prohibited until 4 months after the last dose.

Drug Preparation and Storage

Before intravenous infusion, the drug must be diluted to a concentration of 1-20mg/mL using 0.9% Sodium Chloride Injection or 5% Dextrose Injection.

After dilution, the solution can be stored at room temperature for no more than 8 hours or refrigerated for no more than 24 hours. Freezing or shaking should be avoided.

Cemiplimab Administration Monitoring

Baseline and Regular Laboratory Tests

Liver Function: AST, ALT, and total bilirubin (tested at baseline and once every 3 weeks). If ALT/AST > 3 times the upper limit of normal (ULN), administration must be suspended.

Thyroid Function: TSH and free T4 (tested at baseline and regularly).

Renal Function: Monitor creatinine levels and urine output (the incidence of nephritis is 0.6%).

Imaging and Symptom Monitoring

Pneumonitis Screening: Perform chest CT on patients with persistent cough or dyspnea.

Skin Toxicity: Rash (25%) and pruritus (15%) are common. Severe cases require biopsy to rule out bullous dermatitis.