Tecvayli (Teclistamab): Uses, Dosage & Side Effects
Bispecific antibody for relapsed or refractory multiple myeloma
Tecvayli (teclistamab) is a bispecific antibody used for the treatment of adults with relapsed or refractory multiple myeloma who have received at least three prior lines of therapy. It works by simultaneously binding to BCMA on myeloma cells and CD3 on T cells, redirecting the immune system to attack cancer cells. Tecvayli is administered as a subcutaneous injection under medical supervision and requires careful monitoring for cytokine release syndrome, neurological toxicity, and infections.
Quick Facts
Key Takeaways
- Tecvayli is a bispecific T-cell engager antibody targeting BCMA on myeloma cells and CD3 on T cells, enabling immune-mediated destruction of cancer cells.
- It is approved for adults with relapsed or refractory multiple myeloma after at least three prior therapies, including an immunomodulatory agent, proteasome inhibitor, and anti-CD38 antibody.
- Cytokine release syndrome (CRS) occurs in a majority of patients, primarily with the initial step-up doses, and requires medical monitoring for at least 48 hours after the first three injections.
- Treatment follows a step-up dosing schedule: 0.06 mg/kg (day 1), 0.3 mg/kg (day 4), then 1.5 mg/kg weekly maintenance, with possible bi-weekly dosing after 6 months.
- Patients should not receive live vaccines from four weeks before until four weeks after Tecvayli treatment, and must be monitored regularly for infections and blood count changes.
What Is Tecvayli and What Is It Used For?
Tecvayli contains the active substance teclistamab and belongs to a class of medications known as bispecific T-cell engager antibodies. It has been developed specifically for the treatment of multiple myeloma, a blood cancer that originates in plasma cells within the bone marrow. Plasma cells are a type of white blood cell responsible for producing antibodies, and when they become cancerous, they proliferate uncontrollably and can crowd out healthy blood cells, weaken bones, and impair kidney function.
Multiple myeloma is the second most common blood cancer worldwide, with an estimated 176,000 new cases diagnosed globally each year according to the World Health Organization. Despite significant advances in treatment over the past two decades, most patients eventually relapse, making new therapeutic approaches essential. Tecvayli was approved by the European Medicines Agency (EMA) under a conditional marketing authorization and by the U.S. Food and Drug Administration (FDA) under accelerated approval for patients who have exhausted standard treatment options.
How Does Tecvayli Work?
Tecvayli is an antibody – a type of protein engineered to recognize and attach to specific targets in the body. What makes Tecvayli unique is its bispecific design: it has two binding arms, each targeting a different protein. One arm binds to B-cell maturation antigen (BCMA), a protein highly expressed on the surface of myeloma cells. The other arm binds to cluster of differentiation 3 (CD3), a protein found on T cells, which are key soldiers of the immune system.
By bridging BCMA-expressing myeloma cells with CD3-expressing T cells, Tecvayli effectively brings the patient's own immune cells into direct contact with cancer cells. This proximity activates the T cells, triggering them to release cytotoxic substances that kill the myeloma cells. This mechanism of action is known as T-cell redirection and represents a fundamentally different approach compared to traditional chemotherapy, which targets rapidly dividing cells indiscriminately.
In the pivotal MajesTEC-1 clinical trial, Tecvayli demonstrated an overall response rate of approximately 63% in heavily pre-treated patients, with 39.4% achieving a very good partial response or better. These results were particularly noteworthy given that the patients enrolled had already received a median of five prior lines of therapy. The median duration of response was 18.4 months, indicating that for many patients, the responses were durable and clinically meaningful.
Tecvayli is prescribed only when at least three different types of prior treatment have been tried and have either not worked or stopped working. This includes an immunomodulatory agent (such as lenalidomide), a proteasome inhibitor (such as bortezomib), and an anti-CD38 monoclonal antibody (such as daratumumab).
What Should You Know Before Taking Tecvayli?
Contraindications
Tecvayli should not be administered if you have a known allergy (hypersensitivity) to teclistamab or any of the other ingredients in the formulation, including disodium edetate, concentrated acetic acid, polysorbate 20, sodium acetate trihydrate, sucrose, and water for injections. If you are unsure whether you may be allergic to any component, discuss this with your healthcare provider before treatment begins.
Warnings and Precautions
Before receiving Tecvayli, it is essential to inform your doctor if any of the following apply to you:
- History of stroke or seizures: If you have experienced a stroke or seizure within the past 6 months, your doctor needs to carefully evaluate the risks before starting treatment.
- Hepatitis B infection: Tecvayli can cause reactivation of the hepatitis B virus. Your doctor will test for hepatitis B before treatment and monitor you during and after therapy. If you notice increased fatigue or yellowing of the skin or eyes, report this immediately.
- Active infections: Your blood will be tested for signs of infection before starting Tecvayli. Any active infection must be treated before the first dose is given.
Contact your healthcare team immediately if you experience any of the following during or after treatment:
- Cytokine release syndrome (CRS): Fever, chills, nausea, headache, rapid heartbeat, dizziness, or difficulty breathing
- Neurological symptoms (ICANS): Confusion, reduced alertness, drowsiness, difficulty writing or speaking
- Progressive multifocal leukoencephalopathy (PML): Blurred or double vision, speech difficulties, limb weakness, balance problems, numbness, memory loss
- Signs of infection: Fever, chills, shaking, cough, shortness of breath, rapid breathing and heart rate
Vaccinations
You should not receive live vaccines from four weeks before treatment until four weeks after your last dose of Tecvayli. Live vaccines contain weakened forms of viruses or bacteria that, in immunocompromised patients, could potentially cause the infection they are designed to prevent. Discuss your vaccination status with your doctor before starting treatment, and ensure all necessary inactivated vaccines are up to date. COVID-19 vaccination, seasonal influenza, and pneumococcal vaccines should be discussed with your healthcare team as part of your treatment plan.
Pregnancy and Breastfeeding
The effects of Tecvayli on an unborn child are not fully known. It is not established whether the drug passes into breast milk. Given the mechanism of action and the potential for immune system effects, the following precautions must be observed:
- Women of childbearing potential must use effective contraception during treatment and for 5 months after the last dose of Tecvayli.
- Male patients with partners who may become pregnant must use effective contraception during treatment and for 3 months after the last dose.
- Breastfeeding should be discontinued during treatment and for 5 months after the last dose. The decision to breastfeed or continue therapy should be made in consultation with your doctor, weighing the benefits of treatment against the potential risks to the infant.
- If you or your partner become pregnant during treatment, inform your healthcare team immediately.
Driving and Operating Machinery
Tecvayli can cause fatigue, dizziness, and confusion. Patients should not drive, operate tools or heavy machinery, or engage in activities that could be dangerous until at least 48 hours after receiving the third dose (the first full maintenance dose), or as directed by their physician. The neurological effects associated with cytokine release syndrome and ICANS may impair cognitive and motor function, and patients should exercise caution until they understand how Tecvayli affects them individually.
Drug Interactions
Inform your doctor about all medications you are taking, including prescription medicines, over-the-counter drugs, and herbal supplements. While specific drug-drug interaction studies for teclistamab have not been conducted, the release of cytokines during CRS can affect the activity of cytochrome P450 (CYP) enzymes. This means that the metabolism of other drugs may be altered during the initial treatment phase when CRS is most likely to occur. Particular caution is warranted with:
- CYP substrates with narrow therapeutic indices (such as warfarin, cyclosporine, or certain antiepileptics), as their blood levels may fluctuate unpredictably during CRS episodes
- Immunosuppressive medications that may compound the risk of infection
- Other immunotherapy agents that could potentiate immune-mediated adverse effects
Sodium and Excipient Information
Tecvayli contains less than 1 mmol (23 mg) sodium per dose, making it essentially sodium-free. It also contains polysorbate 20 (0.4 mg per ml), which may cause allergic reactions in rare cases. Inform your doctor if you have any known allergies to excipients.
How Does Tecvayli Interact with Other Drugs?
Although formal drug-drug interaction studies have not been performed with teclistamab, the pharmacological mechanism of bispecific T-cell engagers raises important considerations. The cytokine release that occurs during CRS can suppress or induce hepatic CYP450 enzyme activity, potentially altering the pharmacokinetics of concomitant medications. This is particularly relevant during the step-up dosing phase when CRS is most common and most intense.
Healthcare providers should monitor drug levels and clinical effects of concomitant medications closely, especially those with narrow therapeutic windows. Dose adjustments may be necessary during the initial weeks of Tecvayli therapy. Below is an overview of key interaction categories:
| Interaction Type | Examples | Concern | Recommendation |
|---|---|---|---|
| Narrow therapeutic index CYP substrates | Warfarin, cyclosporine, phenytoin, theophylline | CRS-mediated cytokine release may alter CYP450 enzyme activity, causing unpredictable drug levels | Monitor drug levels closely; adjust doses as needed during step-up phase |
| Live vaccines | MMR, varicella, BCG, oral polio, yellow fever | Risk of vaccine-strain infection in immunocompromised patients | Avoid from 4 weeks before until 4 weeks after treatment |
| Immunosuppressants | Corticosteroids (chronic use), azathioprine, mycophenolate | Compounded risk of serious infections and reduced T-cell efficacy | Evaluate risk-benefit; consider dose reduction or alternative agents |
| Other immunotherapies | Checkpoint inhibitors, CAR-T cell therapy, other bispecific antibodies | Potentiated immune-related adverse effects, including severe CRS and ICANS | Avoid concurrent use; allow adequate washout periods |
| Anticoagulants | Warfarin, heparin, DOACs | Thrombocytopenia from Tecvayli increases bleeding risk | Monitor platelet counts and coagulation parameters frequently |
Patients should maintain an up-to-date medication list and share it with every healthcare provider involved in their care. Any new medications, including over-the-counter drugs and supplements, should be discussed with the treating oncologist before use during Tecvayli therapy.
What Is the Correct Dosage of Tecvayli?
Tecvayli dosing follows a carefully designed step-up schedule to minimize the risk of severe cytokine release syndrome. The dose is calculated based on the patient's actual body weight, and all injections are administered by healthcare professionals in a clinical setting. The step-up approach gradually introduces the immune system to the drug, reducing the intensity of the initial immune activation.
Step-Up Dosing Phase
Step-Up Dose 1
Dose: 0.06 mg/kg body weight
Formulation: Tecvayli 10 mg/ml vial
Monitoring: 48-hour observation period after injection
Step-Up Dose 2 (2–7 days after dose 1)
Dose: 0.3 mg/kg body weight
Formulation: Tecvayli 10 mg/ml vial
Monitoring: 48-hour observation period after injection
Maintenance Dose 1 (2–7 days after dose 2)
Dose: 1.5 mg/kg body weight
Formulation: Tecvayli 90 mg/ml vial
Monitoring: 48-hour observation period after injection
Maintenance Phase
After the initial three doses, the maintenance dose of 1.5 mg/kg is administered once weekly. Patients should remain near a healthcare facility after the first three doses in case side effects develop. After 6 months of weekly treatment, if the patient continues to benefit, the doctor may decide to extend the dosing interval to every two weeks (bi-weekly).
| Phase | Dose | Frequency | Formulation | Monitoring |
|---|---|---|---|---|
| Step-up 1 | 0.06 mg/kg | Day 1 | 10 mg/ml | 48-hour observation |
| Step-up 2 | 0.3 mg/kg | 2–7 days after dose 1 | 10 mg/ml | 48-hour observation |
| Maintenance (first 6 months) | 1.5 mg/kg | Once weekly | 90 mg/ml | 48-hour observation (first dose); routine monitoring thereafter |
| Maintenance (after 6 months) | 1.5 mg/kg | Every 2 weeks (if responding) | 90 mg/ml | Routine monitoring |
Children and Adolescents
Tecvayli should not be given to children or adolescents under 18 years of age. The safety and efficacy of teclistamab in pediatric patients have not been established, and no clinical data are available for this age group. Multiple myeloma is exceedingly rare in children, and treatment decisions for pediatric hematological malignancies should follow specialized pediatric oncology protocols.
Elderly Patients
No specific dose adjustments are required for elderly patients. In the MajesTEC-1 clinical trial, a significant proportion of enrolled patients were aged 65 years and older, which reflects the typical age distribution of multiple myeloma. The safety and efficacy profile was generally consistent across age groups, though elderly patients may be at higher risk for certain adverse events, particularly infections, and should be monitored accordingly.
Pre-Medications
Before each of the first three doses, pre-medications are administered 1 to 3 hours prior to reduce the risk and severity of CRS. These typically include:
- Corticosteroids (such as dexamethasone) to reduce inflammation
- Antihistamines (such as diphenhydramine) to reduce allergic reactions
- Antipyretics (such as paracetamol/acetaminophen) to reduce fever
Your doctor may also prescribe pre-medications for subsequent doses depending on your individual response and any symptoms experienced with prior doses.
Missed Dose
It is very important to attend all scheduled appointments. If you miss an appointment, contact your healthcare team to reschedule as soon as possible. The dosing interval should be maintained to ensure optimal treatment efficacy. Your doctor will advise on how to resume treatment based on the length of the delay and your individual clinical situation.
Overdose
Since Tecvayli is always administered by healthcare professionals in a clinical setting, overdose is unlikely. However, if an overdose were to occur, the medical team would monitor the patient closely for signs of adverse effects, particularly cytokine release syndrome and neurological symptoms, and provide supportive care as needed.
What Are the Side Effects of Tecvayli?
Like all medicines, Tecvayli can cause side effects, although not everyone experiences them. The side effect profile reflects the drug's immune-modulating mechanism of action. Cytokine release syndrome is the most characteristic adverse effect and occurs when the bispecific antibody activates T cells, causing a surge of inflammatory cytokines. The frequency and severity of CRS typically decrease with subsequent doses as the body adapts to the treatment.
Below is a comprehensive overview of side effects organized by frequency. The frequencies are defined according to international medical convention:
Very Common Side Effects
Serious:
- Cytokine release syndrome (CRS) – fever, chills, nausea, headache, rapid heartbeat, dizziness, breathing difficulty
- Low immunoglobulin levels (hypogammaglobulinemia) – increased susceptibility to infections
- Low neutrophils (neutropenia) – increased risk of bacterial infections
- Infections – including pneumonia, COVID-19, upper respiratory tract infections, and urinary tract infections
Blood and laboratory:
- Low red blood cells (anemia) – fatigue, pallor, shortness of breath
- Low platelets (thrombocytopenia) – increased bruising and bleeding risk
- Low white blood cells (leukopenia, lymphopenia)
- Low phosphate, magnesium, or potassium levels
- Elevated calcium levels (hypercalcemia)
- Elevated alkaline phosphatase
General:
- Decreased appetite, nausea, diarrhea, constipation, vomiting, abdominal pain
- Headache, peripheral neuropathy (tingling, numbness, pain)
- Muscle cramps, high blood pressure, low blood pressure
- Bleeding, cough, shortness of breath (dyspnea)
- Fever, severe fatigue, pain, muscle aches
- Swollen hands, ankles, or feet (edema)
- Injection site reactions – redness, itching, swelling, pain, bruising, rash
Common Side Effects
- Sepsis – severe whole-body infection
- Cellulitis – skin infection causing redness
- Febrile neutropenia – low neutrophils with fever
- Low fibrinogen levels – impaired blood clotting
- Encephalopathy – altered brain function
- ICANS (immune effector cell-associated neurotoxicity) – confusion, reduced alertness, speech/writing difficulties, drowsiness
- Low calcium or sodium levels
- High potassium levels (hyperkalemia)
- Low albumin, low blood sugar (hypoglycemia)
- Low blood oxygen (hypoxia)
- Elevated liver enzymes (GGT, transaminases), creatinine, amylase, lipase
- Prolonged clotting times (elevated INR, prolonged aPTT)
Uncommon Side Effects
- Progressive multifocal leukoencephalopathy (PML) – a serious, potentially fatal brain infection causing blurred or lost vision, speech difficulties, limb weakness, balance problems, numbness, memory loss, or confusion
Rare / Not Yet Fully Characterized
- Hepatitis B reactivation in patients with prior infection
- Tumor lysis syndrome in patients with high tumor burden
- Severe, prolonged cytopenias requiring growth factor support or transfusions
It is important to report suspected side effects after the drug has been authorized, as this enables ongoing monitoring of the benefit-risk balance. Healthcare professionals and patients can report adverse effects to their national pharmacovigilance authority (e.g., the FDA MedWatch program in the United States, the Yellow Card Scheme in the United Kingdom, or the EMA EudraVigilance system in the European Union).
How Should You Store Tecvayli?
Tecvayli is a hospital-administered medication, meaning that storage and preparation are managed entirely by healthcare professionals. Patients do not need to handle or store this drug themselves. However, for complete transparency and patient education, the following storage requirements apply:
- Temperature: Store in a refrigerator at 2°C to 8°C (36°F to 46°F)
- Freezing: Do not freeze under any circumstances
- Light protection: Keep in the original carton to protect from light
- Expiry: Do not use after the expiration date printed on the carton and vial label
- Before use: Vials should be allowed to equilibrate to room temperature (15–30°C) for at least 15 minutes before preparation. Do not heat the solution by any other means.
- Inspection: The solution should be colorless to light yellow. Do not use if the solution is discolored, cloudy, or contains visible particles.
Unused medicine should not be disposed of via household waste or wastewater. Healthcare facilities follow specific disposal protocols for biological medicines to protect the environment. The vials are single-use only and should not be re-entered after initial puncture.
What Does Tecvayli Contain?
Tecvayli is supplied as a solution for injection in glass vials. Two different concentrations are available, each designed for a specific phase of the treatment regimen:
| Strength | Vial Volume | Total Content | Use |
|---|---|---|---|
| 10 mg/ml | 3 ml | 30 mg teclistamab | Step-up doses 1 and 2 |
| 90 mg/ml | 1.7 ml | 153 mg teclistamab | Maintenance doses |
Inactive Ingredients (Excipients)
In addition to the active substance teclistamab, Tecvayli contains the following inactive ingredients:
- Disodium edetate (dihydrate)
- Concentrated acetic acid
- Polysorbate 20
- Sodium acetate trihydrate
- Sucrose
- Water for injections
The solution is a colorless to light yellow liquid. Each carton contains one single-use glass vial. Vials of different strengths (10 mg/ml and 90 mg/ml) must not be combined to achieve the maintenance dose. Aseptic technique must be used throughout preparation and administration. The maximum injection volume per injection site is 2.0 ml; doses requiring more than 2.0 ml should be divided equally across multiple syringes.
Marketing Authorization Holder
Tecvayli is manufactured by Janssen Biologics B.V. (Leiden, Netherlands) and Janssen Pharmaceutica NV (Beerse, Belgium). The marketing authorization is held by Janssen-Cilag International NV, Beerse, Belgium. This medicine was granted conditional marketing authorization by the European Medicines Agency, meaning that additional data are expected and reviewed at least annually.
Frequently Asked Questions About Tecvayli
References
This article is based on the following peer-reviewed sources and regulatory documents:
- European Medicines Agency (EMA). Tecvayli (teclistamab) – Summary of Product Characteristics. Last updated 2025. Available at: EMA Tecvayli EPAR.
- Moreau P, et al. Teclistamab in Relapsed or Refractory Multiple Myeloma (MajesTEC-1). New England Journal of Medicine. 2022;387(6):495–505. DOI: 10.1056/NEJMoa2203478.
- U.S. Food and Drug Administration (FDA). Tecvayli Prescribing Information. 2022. Available at: FDA Tecvayli Label.
- National Comprehensive Cancer Network (NCCN). Clinical Practice Guidelines in Oncology: Multiple Myeloma. Version 2.2025.
- Dimopoulos MA, et al. ESMO Clinical Practice Guidelines for diagnosis, treatment, and follow-up of multiple myeloma. Annals of Oncology. 2021;32(3):309–322.
- World Health Organization (WHO). International Agency for Research on Cancer (IARC). Global Cancer Observatory: Multiple Myeloma Fact Sheet. 2024.
- Lee DW, et al. ASTCT Consensus Grading for Cytokine Release Syndrome and Neurologic Toxicity Associated with Immune Effector Cells. Biology of Blood and Marrow Transplantation. 2019;25(4):625–638.
Editorial Team
This article has been written and reviewed by the iMedic Medical Editorial Team, consisting of licensed physicians specializing in oncology, hematology, and clinical pharmacology.
iMedic Medical Editorial Team – specialists in oncology and pharmacology with extensive experience in patient education.
iMedic Medical Review Board – independent panel of hematologists and oncologists who verify accuracy according to EMA, FDA, and NCCN guidelines.
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