Teizeild (Teplizumab)

What Is Teizeild and What Is It Used For?

Teizeild (teplizumab) is an anti-CD3 monoclonal antibody used to delay the onset of stage 3 type 1 diabetes in adults and children aged 8 years and older who have been diagnosed with stage 2 type 1 diabetes. It is the first disease-modifying therapy approved for this indication.

Teizeild contains the active substance teplizumab, which belongs to a class of medications known as monoclonal antibodies. These are laboratory-engineered proteins designed to recognise and bind to specific targets in the body. In the case of teplizumab, the target is a molecule called CD3, found on the surface of T cells (a type of white blood cell that plays a central role in the immune system).

Type 1 diabetes is an autoimmune disease in which the body's own immune system mistakenly attacks and destroys the insulin-producing beta cells in the pancreas. Insulin is a hormone essential for regulating blood sugar (glucose) levels. Over time, the progressive destruction of beta cells leads to an absolute deficiency of insulin, requiring lifelong insulin therapy.

The disease develops through three recognised stages. In stage 1, the individual has two or more diabetes-related autoantibodies but maintains normal blood sugar levels and has no symptoms. In stage 2, autoantibodies are present and blood sugar levels begin to become abnormal (a state called dysglycemia), though the person does not yet have sustained high blood sugar. In stage 3, the pancreas can no longer produce sufficient insulin, resulting in clinical diabetes that requires insulin treatment.

Before starting treatment with Teizeild, your doctor will confirm stage 2 type 1 diabetes by verifying the presence of two or more diabetes-related autoantibodies (such as GAD65, IA-2, ZnT8, or insulin autoantibodies) and demonstrating abnormal blood sugar regulation (dysglycemia) without overt hyperglycemia. This diagnostic step is critical to ensure the medication is used in the appropriate patient population.

How does Teizeild work?

Teplizumab works by binding to CD3, an activating molecule on the surface of T cells. When teplizumab attaches to CD3, it inactivates the specific subset of T cells that are responsible for attacking and destroying pancreatic beta cells. This immunomodulatory effect helps preserve the remaining beta cell function, effectively slowing the autoimmune destruction that drives the progression from stage 2 to stage 3 type 1 diabetes.

Research from the landmark phase 3 clinical trial demonstrated that teplizumab significantly delayed the median time to clinical diagnosis of stage 3 type 1 diabetes compared to placebo. This delay provides patients with additional time during which their own pancreas continues to produce insulin, potentially reducing the long-term complications associated with the disease.

It is important to understand that Teizeild does not cure type 1 diabetes and does not eliminate the underlying autoimmune process entirely. Rather, it modulates the immune response to slow disease progression. Patients receiving Teizeild should continue to be monitored for the eventual development of stage 3 diabetes and should maintain regular follow-up appointments with their healthcare team.

What Should You Know Before Receiving Teizeild?

You should not receive Teizeild if you are allergic to teplizumab or any of its excipients. Important precautions include screening for active infections, reviewing vaccination status, and understanding the risks of cytokine release syndrome, lymphopenia, and hypersensitivity reactions.

Contraindications

Teizeild is contraindicated in individuals with a known hypersensitivity (allergy) to teplizumab or to any of the other ingredients in the formulation, including disodium phosphate, sodium dihydrogen phosphate, polysorbate 80 (E 433), sodium chloride, and water for injections. If you have experienced allergic reactions to monoclonal antibody therapies in the past, discuss this with your doctor before starting treatment.

Warnings and Precautions

Before receiving Teizeild, inform your healthcare provider about all your medical conditions, particularly if you:

• Have an active or serious infection – or a recurring infection that does not resolve. Active infections should be treated before starting Teizeild, as the medication affects immune function and may impair the body's ability to fight infections
• Have recently received or plan to receive a vaccine – Teizeild may reduce the effectiveness of certain vaccines. Your doctor will advise you on appropriate timing for vaccinations before and after treatment. Live vaccines should generally be avoided near the treatment period

Teizeild can decrease lymphocyte counts (a type of white blood cell essential for fighting infections). Your doctor will perform blood tests to monitor your liver function and complete blood count before and during treatment. Significant or prolonged lymphopenia may increase your susceptibility to infections.

Pregnancy and Breastfeeding

Tell your doctor if you are pregnant, think you might be pregnant, or are planning to have a baby. Teizeild may cause harm to an unborn child and is not recommended during pregnancy or in women of childbearing potential who are not using effective contraception.

It is not known whether teplizumab passes into breast milk or whether it could affect a breastfed infant. As a precaution, breastfeeding should be discontinued during treatment with Teizeild and for at least 30 days after the last dose.

Driving and Operating Machinery

Teizeild may have a minor effect on your ability to drive and use machines. If you experience fatigue during or after treatment, do not drive or operate machinery until you have discussed this with your healthcare provider. Fatigue is one of the very common side effects reported with this medication.

Drug Interactions

Tell your doctor about all medications you are currently taking, have recently taken, or plan to take. While specific drug interaction studies for teplizumab are limited, the following considerations are important:

What Is the Correct Dosage of Teizeild?

Teizeild is given as a once-daily intravenous infusion for 14 consecutive days. The dose is calculated based on body surface area (BSA). Each infusion takes at least 30 minutes and must be administered by qualified healthcare professionals in a clinical setting.

Teizeild must be administered by healthcare professionals who have access to appropriate medical support to manage any serious adverse reactions that may occur. The medication is given as an intravenous (IV) infusion, meaning it is delivered directly into a vein through a drip line.

Dosing Schedule

The treatment course consists of 14 consecutive daily infusions. Your doctor will calculate your specific dose based on your body surface area (BSA), which is a measurement of the total area of your skin determined using your height and weight (typically calculated using the Mosteller formula).

The dosage is gradually increased over the first few days of treatment, with the full dose administered from day 5 onwards. This dose-escalation approach helps minimise the risk of cytokine release syndrome during the initial phase of treatment.

Premedication

During the first 5 days of treatment, you will receive additional oral medications to reduce the risk of cytokine release syndrome. These premedications include:

• Anti-inflammatory drugs such as ibuprofen or naproxen – or other fever-reducing medications such as paracetamol (acetaminophen)
• An antihistamine – used to prevent or reduce allergic-type symptoms
• An anti-nausea medication – to help prevent nausea and vomiting

Adults and Children (8 years and older)

The same BSA-based dosing approach is used for both adults and children aged 8 years and older. There is no separate dosing regimen for elderly patients. The safety and efficacy of Teizeild have not been established in children under 8 years of age, and use in this age group is not recommended.

Missed Dose

If you miss a scheduled infusion, your doctor or nurse will continue treatment on the next scheduled day. You will not receive two infusions on the same day to make up for a missed dose. The total treatment course remains 14 infusion days.

Overdose

If you receive too much Teizeild, your healthcare team will monitor and treat any side effects that may occur. Since the medication is administered by trained healthcare professionals in a supervised clinical setting, the risk of accidental overdose is low. In the event of an overdose, supportive care and monitoring of vital signs, liver function, and blood counts would be provided.

How Does Teizeild Interact with Other Drugs?

Formal drug interaction studies for teplizumab are limited. Key interactions to be aware of include the timing of vaccinations (both live and inactivated), concurrent use of immunosuppressive medications, and other biologic therapies that may have additive effects on the immune system.

Because teplizumab is a monoclonal antibody that modulates T cell function, its primary interaction concerns relate to other agents that affect the immune system. Unlike small-molecule drugs that are metabolised by liver enzymes (such as CYP450), monoclonal antibodies are degraded through proteolytic pathways, which generally reduces the risk of traditional pharmacokinetic drug interactions.

Vaccines

Teizeild can affect how well certain vaccines work. Since the medication modulates T cell function, the immune response to vaccination may be diminished during and for a period after treatment. Your doctor will provide specific guidance on the appropriate timing for different types of vaccines:

• Live vaccines (such as MMR, varicella, or yellow fever) should be administered with careful consideration of timing relative to Teizeild treatment, as reduced T cell function could potentially allow vaccine-strain organisms to replicate
• Inactivated vaccines (such as influenza injection or hepatitis B) may produce a reduced immune response if given too close to the treatment course

Always inform your healthcare provider that you have been treated with Teizeild before receiving any vaccination. Your doctor will determine the most appropriate schedule based on the type of vaccine and the time elapsed since your treatment.

Immunosuppressive Medications

Concurrent use of Teizeild with other immunosuppressive agents (such as cyclosporine, tacrolimus, mycophenolate mofetil, or azathioprine) may result in additive immunosuppression. This combination could increase the risk of infections and other immune-related complications. If you are taking any immunosuppressive medication, your doctor will carefully weigh the potential risks and benefits before initiating treatment with Teizeild.

Other Biologic Therapies

The use of Teizeild in combination with other biologic therapies (such as other monoclonal antibodies or TNF inhibitors) has not been formally studied. Given the potential for overlapping effects on the immune system, inform your doctor about all biologic medications you are taking or have recently taken.

What Are the Side Effects of Teizeild?

The most common side effects of Teizeild include decreased lymphocyte counts, low platelet counts, low white blood cell counts, headache, nausea, vomiting, elevated liver enzymes, skin rash, itching, fever, and fatigue. Cytokine release syndrome (CRS) is a common serious side effect that typically occurs during the first 5 days of treatment.

Like all medicines, Teizeild can cause side effects, although not everyone experiences them. Your doctor and nurse will monitor you for serious side effects during and after each infusion and will provide treatment as needed. The side effects are listed below by how frequently they occur.

Serious Side Effects

Tell your doctor or nurse immediately if you experience any of the following serious side effects:

Other Side Effects

Your doctor or nurse may pause or discontinue treatment if you develop liver problems, a serious infection, or if your blood values remain too low. It is important to attend all scheduled blood test appointments during and after treatment to allow your healthcare team to detect and manage side effects promptly.

How Should Teizeild Be Stored?

Teizeild must be stored in a refrigerator (2°C to 8°C) and must not be frozen. It should be kept in the original carton to protect from light and stored upright. Healthcare professionals are responsible for proper storage and handling.

The storage of Teizeild is the responsibility of your healthcare provider, pharmacist, or nurse. Patients typically do not need to store this medication at home, as it is administered in a clinical setting. However, understanding the storage requirements provides useful context about the medication's stability.

Unopened Vials

• Store in a refrigerator at 2°C to 8°C (36°F to 46°F)
• Do not freeze the vials
• Keep the vials in the original carton to protect from light
• Store in an upright position
• Do not use after the expiry date printed on the carton and vial label

After Dilution

Once Teizeild has been diluted for administration, the following stability conditions apply:

• IV bags: Stable for up to 6 hours at room temperature (15°C–25°C)
• Syringe infusions: Stable for up to 12 hours refrigerated (2°C–8°C), followed by up to 6 hours at room temperature

From a microbiological perspective, it is recommended that the diluted product be used immediately. Any unused solution should be discarded in accordance with local regulations for pharmaceutical waste disposal.

What Does Teizeild Contain?

Each vial of Teizeild contains 2 mg of teplizumab at a concentration of 1 mg/mL. Inactive ingredients include disodium phosphate, sodium dihydrogen phosphate, polysorbate 80 (E 433), sodium chloride, and water for injections.

Teizeild is supplied as a concentrate for solution for infusion. The solution is clear and colourless. It is available in cartons containing 1, 10, or 14 vials, though not all pack sizes may be marketed in every country.

Active Ingredient

The active substance is teplizumab, an anti-CD3 monoclonal antibody. Each 2 mL vial contains 2 mg of teplizumab (concentration: 1 mg/mL).

Inactive Ingredients (Excipients)

• Disodium phosphate (buffer)
• Sodium dihydrogen phosphate (buffer)
• Polysorbate 80 (E 433) – surfactant (0.10 mg per vial)
• Sodium chloride (tonicity agent)
• Water for injections (solvent)

The formulation is essentially sodium-free, containing less than 1 mmol (23 mg) of sodium per vial. Patients with sodium-restricted diets can safely receive this medication without concern about sodium content contributing to their dietary intake.

Preparation for Administration

Teizeild requires a two-step dilution process before administration. First, the concentrate is diluted 1:10 with sodium chloride 0.9% solution to achieve a concentration of 100 micrograms/mL. Then, the appropriate volume for the patient's calculated dose is further diluted in either an IV bag or syringe for infusion. This preparation is performed by trained healthcare professionals using aseptic technique.

Frequently Asked Questions About Teizeild