LIBTAYO (Cemiplimab)

What Is LIBTAYO and What Is It Used For?

LIBTAYO (cemiplimab) is a cancer immunotherapy medicine containing a monoclonal antibody that targets the PD-1 receptor on T cells. By blocking PD-1, LIBTAYO restores the immune system's ability to detect and destroy cancer cells. It is approved for adults with advanced skin cancer, lung cancer, and cervical cancer.

LIBTAYO belongs to a class of anticancer medicines known as immune checkpoint inhibitors. The immune system normally uses checkpoint proteins like PD-1 (programmed death-1) to prevent T cells from attacking healthy tissues. Cancer cells can exploit this mechanism by expressing PD-L1 (programmed death-ligand 1) on their surface, which binds to PD-1 on T cells and effectively switches them off. Cemiplimab is a fully human immunoglobulin G4 (IgG4) monoclonal antibody that binds to PD-1 with high affinity, blocking the interaction between PD-1 and its ligands PD-L1 and PD-L2. This releases the brake on the immune response and enables T cells to mount an effective anti-tumour immune response.

LIBTAYO is currently approved for use in adults for the following indications:

• Advanced cutaneous squamous cell carcinoma (CSCC): This is the most common form of skin cancer after basal cell carcinoma. LIBTAYO is used for patients with metastatic or locally advanced CSCC who are not candidates for curative surgery or curative radiation therapy. Clinical trials have demonstrated tumour response rates of approximately 47%, with many patients achieving durable responses lasting more than six months.
• Adjuvant treatment of CSCC after surgery: Following surgical removal of CSCC in patients at high risk of recurrence, LIBTAYO is used to reduce the likelihood of the cancer returning. The KEYNOTE-630/EMPOWER-CSCC-2 trials have demonstrated significant improvements in disease-free survival.
• Advanced basal cell carcinoma (BCC): For patients who have previously been treated with a hedgehog pathway inhibitor (HHI) such as vismodegib or sonidegib, where that treatment did not work well or was not tolerated. BCC is the most common type of cancer worldwide, and LIBTAYO provides an important second-line systemic therapy option.
• Advanced non-small cell lung cancer (NSCLC): LIBTAYO may be used either as a single agent in patients whose tumours express PD-L1 at 50% or more (as measured by an approved test), or in combination with platinum-based chemotherapy, for first-line treatment of advanced NSCLC without EGFR, ALK, or ROS1 genomic aberrations.
• Cervical cancer: For patients with recurrent or metastatic cervical cancer that has progressed on or after prior platinum-based chemotherapy.

What Should You Know Before Receiving LIBTAYO?

Before starting LIBTAYO, your doctor will review your complete medical history. LIBTAYO must not be given if you are allergic to cemiplimab. Special caution is needed if you have an autoimmune disease, have received an organ transplant, or have lung, liver, or kidney problems. Women must use effective contraception during treatment and for at least 4 months after the last dose.

Contraindications

You should not receive LIBTAYO if:

• Allergy to cemiplimab or any of the other ingredients in the medicine (L-histidine, L-histidine monohydrochloride monohydrate, L-proline, sucrose, polysorbate 80, water for injections). Allergic reactions can range from mild skin reactions to severe, life-threatening anaphylaxis.

If you are unsure whether you may be allergic or have had a previous reaction to a PD-1 or PD-L1 inhibitor, discuss this with your doctor before starting treatment.

Warnings and Precautions

Tell your doctor or nurse before receiving LIBTAYO if you have or have had any of the following conditions, as they may increase the risk or severity of immune-mediated adverse reactions:

• Autoimmune disease: Conditions where the immune system attacks the body's own cells (e.g. rheumatoid arthritis, lupus, inflammatory bowel disease, multiple sclerosis, Hashimoto's thyroiditis). LIBTAYO may worsen pre-existing autoimmune conditions or trigger flares, although these are usually mild.
• Organ transplant or allogeneic stem cell transplant: Patients who have received an organ transplant or bone marrow transplant from another person (allogeneic haematopoietic stem cell transplant) are at increased risk of graft rejection and graft-versus-host disease. The decision to use LIBTAYO in these patients requires very careful risk-benefit assessment.
• Lung or breathing problems: Pre-existing pulmonary conditions may increase the risk of immune-mediated pneumonitis.
• Liver problems: Pre-existing hepatic impairment may complicate the monitoring of immune-mediated hepatitis.
• Kidney problems: Renal impairment may increase the risk of immune-mediated nephritis.
• Diabetes: LIBTAYO can cause new-onset type 1 diabetes mellitus or diabetic ketoacidosis. Patients with pre-existing diabetes require particularly close blood glucose monitoring.

Pregnancy and Breastfeeding

LIBTAYO may cause harm to an unborn baby. Based on its mechanism of action, blocking the PD-1 pathway may disrupt immune tolerance of the foetus, potentially leading to foetal harm including increased rates of miscarriage and stillbirth. Animal studies have not been conducted with cemiplimab, but other PD-1 blocking antibodies have been associated with adverse developmental effects.

If you are pregnant, think you may be pregnant, or are planning to become pregnant, do not receive LIBTAYO. Tell your doctor immediately if you become pregnant during treatment.

Women of childbearing potential must use effective contraception during treatment with LIBTAYO and for at least 4 months after the last dose. Discuss suitable contraceptive methods with your doctor.

It is not known whether cemiplimab passes into human breast milk. Because antibodies can be excreted in breast milk and the potential for serious adverse reactions in breastfed infants exists, you should not breastfeed during treatment with LIBTAYO and for at least 4 months after the last dose.

Children and Adolescents

LIBTAYO should not be given to children and adolescents under 18 years of age. The safety and efficacy of cemiplimab have not been established in the paediatric population.

Driving and Operating Machinery

LIBTAYO has no or negligible direct effect on the ability to drive or use machines. However, some side effects such as fatigue can occur. Do not drive or operate machinery if you feel tired or unwell, and wait until you feel better before resuming these activities.

Special Ingredients to Be Aware Of

L-proline: This medicine contains 105 mg L-proline per 7 mL vial (equivalent to 15 mg/mL). L-proline may be harmful for patients with hyperprolinaemia, a rare hereditary disorder that leads to accumulation of L-proline in the body. If you have hyperprolinaemia, do not use this medicine unless recommended by your doctor.

Polysorbate 80: This medicine contains 14 mg polysorbate 80 per 7 mL vial (equivalent to 2 mg/mL). Polysorbates may cause allergic reactions. Tell your doctor if you have any known allergies to polysorbate.

How Does LIBTAYO Interact with Other Drugs?

LIBTAYO has relatively few traditional pharmacokinetic drug interactions because it is a monoclonal antibody cleared through protein catabolism rather than hepatic enzyme metabolism. However, systemic immunosuppressants (including corticosteroids) and certain other drugs can affect its efficacy or increase the risk of adverse events.

Unlike small-molecule drugs that are metabolised by liver enzymes such as CYP450, monoclonal antibodies like cemiplimab are degraded through general protein catabolism. This means traditional drug-drug interactions involving enzyme inhibition or induction are not typically a concern. However, clinically important interactions still exist, primarily related to the pharmacodynamic effects of the drug on the immune system.

Clinically Important Interactions

When LIBTAYO is used in combination with chemotherapy for non-small cell lung cancer, additional drug interactions related to the chemotherapy agents must also be considered. It is essential to read the prescribing information for the specific chemotherapy drugs being used in combination. Always inform your oncologist about all medications you are taking, including over-the-counter medicines, herbal supplements, and vitamins.

What Is the Correct Dosage of LIBTAYO?

LIBTAYO is given as an intravenous infusion of 350 mg every 3 weeks, administered over approximately 30 minutes at a hospital or clinic. For adjuvant CSCC treatment, an alternative regimen of 350 mg every 3 weeks for 12 weeks followed by 700 mg every 6 weeks may be used for up to 48 weeks total.

LIBTAYO is always administered by healthcare professionals in a hospital, clinic, or infusion centre with experience in cancer treatment. You will not self-administer this medicine. Your doctor will determine how many treatment cycles you will receive based on your type of cancer, your response to treatment, and any side effects you experience.

Adults – Standard Dosing

Dose Modifications

Unlike many other cancer treatments, dose reductions of LIBTAYO are not recommended. Instead, management of adverse reactions involves either:

• Withholding (delaying) treatment: Your doctor may delay the next infusion until an immune-mediated adverse reaction has improved to an acceptable level. Corticosteroids or other immunosuppressive treatments may be given during this period.
• Permanently discontinuing treatment: For severe or life-threatening immune-mediated reactions, or for reactions that do not resolve despite appropriate treatment, LIBTAYO may be permanently stopped.

Missed Dose

If you miss a scheduled appointment for LIBTAYO, contact your doctor or treatment centre as soon as possible to arrange a new appointment. It is very important not to miss doses, as this may affect the effectiveness of your treatment. Your doctor will advise when the next dose should be given.

Monitoring During Treatment

During your course of LIBTAYO treatment, you will have regular blood tests to monitor for potential side effects. These tests typically include:

• Complete blood count (to check red blood cells, white blood cells, and platelets)
• Liver function tests (ALT, AST, bilirubin)
• Kidney function tests (creatinine)
• Thyroid function tests (TSH, free T4)
• Blood glucose levels
• Electrolytes and cortisol levels as clinically indicated

What Are the Side Effects of LIBTAYO?

Like all medicines, LIBTAYO can cause side effects. The most common include fatigue, musculoskeletal pain, rash, diarrhoea, anaemia, nausea, and decreased appetite. The most important safety concern with LIBTAYO is the risk of immune-mediated adverse reactions, which can affect virtually any organ and may be severe or life-threatening.

LIBTAYO works by activating the immune system. While this is essential for fighting cancer, the activated immune system can also cause inflammation in healthy organs and tissues. These immune-mediated adverse reactions are the most clinically significant side effects of LIBTAYO and require prompt recognition and treatment. Your doctor will discuss these risks with you before starting treatment.

Side Effects When LIBTAYO Is Used Alone (Monotherapy)

Additional Side Effects When Combined with Chemotherapy

When LIBTAYO is used in combination with chemotherapy for NSCLC, additional side effects may occur due to the chemotherapy agents. The most common additional effects include:

• Hair loss (alopecia)
• High blood sugar (hyperglycaemia)
• Low white blood cell counts (neutropaenia)
• Low platelet counts (thrombocytopaenia)
• Shortness of breath
• Weight loss
• Sleep difficulties (insomnia)
• Low blood albumin levels

Other Reported Side Effects (Frequency Not Known)

• Transplant organ rejection
• Bladder inflammation (cystitis)
• Haemophagocytic lymphohistiocytosis (HLH) – a condition where the immune system produces too many infection-fighting cells, potentially causing enlarged liver/spleen, rash, breathing problems, and kidney/heart complications
• Coeliac disease (gluten intolerance)
• Exocrine pancreatic insufficiency (reduced digestive enzyme production)

If you notice any side effects not listed here, or if any side effect becomes severe, contact your doctor or nurse immediately. Reporting side effects helps ensure ongoing monitoring of the medicine's benefit-risk balance.

How Should LIBTAYO Be Stored?

LIBTAYO must be stored in a refrigerator at 2–8°C (36–46°F) in the original packaging to protect from light. It must not be frozen. Storage and handling are managed by the hospital pharmacy or infusion centre – patients do not need to store this medicine at home.

LIBTAYO is supplied as a concentrate for solution for infusion in single-use vials. As an intravenous medication administered in a clinical setting, patients typically do not need to worry about storage. However, the following information is provided for completeness and for healthcare professionals:

• Unopened vials: Store in a refrigerator at 2–8°C. Keep in the original carton to protect from light. Do not freeze.
• After dilution (room temperature): The diluted solution is chemically and physically stable for up to 8 hours at room temperature (up to 25°C), from the time of preparation to the end of the infusion.
• After dilution (refrigerated): The diluted solution may be stored at 2–8°C for up to 10 days from the time of dilution to the end of the infusion. Allow the solution to reach room temperature before administration.

Do not use LIBTAYO after the expiry date stated on the carton and vial label (EXP). The expiry date refers to the last day of the stated month. Do not save any unused infusion solution for re-use. Any unused medicine or waste material should be disposed of in accordance with local regulations.

Keep all medicines out of the sight and reach of children.

What Does LIBTAYO Contain?

Each 7 mL vial of LIBTAYO contains 350 mg of cemiplimab at a concentration of 50 mg/mL. The solution is clear to slightly opalescent, colourless to pale yellow, and may contain trace amounts of translucent to white particles.

Active Ingredient

The active substance is cemiplimab. Each 7 mL single-use vial contains 350 mg cemiplimab at a concentration of 50 mg/mL. Cemiplimab is a fully human immunoglobulin G4 (IgG4) monoclonal antibody produced by recombinant DNA technology in Chinese hamster ovary (CHO) cell culture.

Inactive Ingredients (Excipients)

The other ingredients are:

• L-histidine
• L-histidine monohydrochloride monohydrate
• L-proline (105 mg per vial)
• Sucrose
• Polysorbate 80 (14 mg per vial)
• Water for injections

Appearance and Packaging

LIBTAYO concentrate for solution for infusion is a clear to slightly opalescent, colourless to pale yellow sterile solution that may contain trace amounts of translucent to white particles. Each carton contains 1 single-use glass vial with 7 mL of concentrate.

Preparation and Administration (For Healthcare Professionals)

LIBTAYO must be diluted before intravenous administration. The concentrate is diluted with either sodium chloride 9 mg/mL (0.9%) solution for injection or glucose 50 mg/mL (5%) solution for injection to a final concentration between 1 mg/mL and 20 mg/mL. The diluted solution is administered as an intravenous infusion over 30 minutes through an intravenous line containing a sterile, non-pyrogenic, low-protein-binding in-line or add-on filter (pore size 0.2–5 µm). For the 700 mg dose, two vials are used.

How Does LIBTAYO Work in the Body?

LIBTAYO works by blocking the PD-1 checkpoint receptor on T cells, preventing cancer cells from switching off the immune response. This restores the ability of T cells to recognise and kill tumour cells. The terminal half-life is approximately 19 days, supporting the 3-weekly dosing schedule.

The immune system plays a critical role in detecting and eliminating cancer cells. However, tumours have evolved sophisticated mechanisms to evade immune surveillance. One of the most important of these is the PD-1/PD-L1 pathway. PD-1 (programmed death-1) is a receptor found on the surface of activated T cells. When PD-1 binds to its ligands – PD-L1 and PD-L2, which are expressed on tumour cells and cells within the tumour microenvironment – it delivers an inhibitory signal to the T cell, suppressing its ability to kill the tumour cell.

Cemiplimab is a fully human IgG4 monoclonal antibody with high affinity and specificity for PD-1. By binding to PD-1 on T cells, cemiplimab blocks the interaction between PD-1 and its ligands. This removes the inhibitory signal, effectively releasing the brake on the immune response, and allows T cells to mount an effective anti-tumour response. The reactivated T cells can then infiltrate the tumour, recognise tumour-associated antigens, and kill cancer cells through cell-mediated cytotoxicity.

This mechanism is particularly relevant in tumours with high mutational burden, such as cutaneous squamous cell carcinoma (CSCC), which develops in sun-damaged skin and typically has a very high number of genetic mutations. These mutations create novel proteins (neoantigens) that can be recognised by the immune system as foreign, making such tumours especially responsive to immune checkpoint blockade. Clinical trials have demonstrated tumour response rates of approximately 44–50% in metastatic CSCC and 32–44% in locally advanced CSCC.

Pharmacokinetic Profile

As a monoclonal antibody, cemiplimab has pharmacokinetic properties typical of this drug class. It is administered intravenously, providing 100% bioavailability. At the recommended dose of 350 mg every 3 weeks, steady-state concentrations are achieved by approximately 4 months (16 weeks) of treatment. The terminal elimination half-life is approximately 19 days, which supports the 3-weekly dosing interval.

Cemiplimab is cleared through two pathways: target-mediated clearance (where the drug is consumed by binding to PD-1) and non-specific clearance (typical protein catabolism). At therapeutic doses, the target-mediated pathway is saturated, and clearance is predominantly non-specific. No dose adjustments are recommended based on age, body weight, sex, race, mild-to-moderate renal impairment, or mild hepatic impairment. The effects of severe renal or hepatic impairment on cemiplimab pharmacokinetics have not been formally studied.

Frequently Asked Questions About LIBTAYO