What Is Tecvayli? 

TECVAYLI™ (also known as teclistamab-cqyv, the generic drug name), is the first in a drug class of bispecific antibodies approved by the U.S. Food and Drug Administration (FDA) to treat myeloma. 

How Does Tecvayli Work? 

Tecvayli is an immunotherapy, a treatment that enhances a patient’s own immune system to attack their myeloma cells. Tecvayli is a bispecific antibody (also called “bispecific therapy”). A bispecific antibody is a laboratory-made monoclonal antibody that uses dual-binding (“bi”) action to kill the targeted myeloma cells. 

Tecvayli has two “arms.” One of those arms binds to the myeloma cell surface by adhering to the B-cell maturation antigen (BCMA). The other arm binds to a local T cell by its CD3 antigen. Tecvayli binds to both the myeloma cell and the T cell. As a result, it brings the myeloma cell and T cell together. Also, it activates the T cell to release cytotoxic granules to destroy the myeloma cell. 

How Does Tecvayli Differ from CAR T-cell Therapy? 

Tecvayli differs from CAR T-cell therapy in that there is no need to collect the patient’s T cells. Instead, Tecvayli engages the patient’s T cells directly after injection. Not having to collect, engineer, and manufacture T cells over the course of several weeks shortens the time-to-treatment for the myeloma patient. The “off-the-shelf” availability of Tecvayli makes it easier to access treatment. 

When Should Tecvayli Be Used as a Treatment? 

Tecvayli is FDA-approved for patients with relapsed or refractory myeloma (RRMM) who have received at least 4 prior lines of therapy, including a proteasome inhibitor, an immunomodulatory agent, and an anti-CD38 monoclonal antibody. 

How Has Tecvayli Been Used in Clinical Trials? 

MajesTEC-1 clinical trial 

The safety of Tecvayli was evaluated in the MajesTEC-1 clinical trial with adult patients with RRMM. Patients received step-up doses of 0.06 mg/kg and 0.3 mg/kg of Tecvayli followed by 1.5 mg/kg of Tecvayli, given by a subcutaneous (SQ) injection once-weekly.

The MajesTEC-3 clinical trial of patients with RRMM is studying Tecvayli in combination with

Tecvayli is also being studied in several other clinical trials as part of different combination therapies, at different doses, and in earlier disease settings.

Demographics of participants in the MajesTEC-1 clinical trial  

  • The median age of patients of 64 years (range of 33 to 84 years)
  • 58% were male. 
  • 81% were white. 
  • 13% were Black. 
  • 2% were Asian. 

How Should Tecvayli Be Administered, Dosed, and Scheduled? 

When Tecvayli is injected, there is a risk that the patient’s immune system may react in a way that causes a cytokine release syndrome (CRS). For this reason, patients begin Tecvayli at a lower dose. The patient’s immune system will likely be able to tolerate a lower dose better.  

At the discretion of the treating doctor, the patient may be admitted to hospital for 48 hours after the administration of each “step-up” dose of Tecvayli. Alternatively, the individual may be monitored on an outpatient basis for CRS and the risk of neurologic toxicity. 

The recommended dosing schedule for Tecvayli is provided in the following table. The two step-up doses of Tecvayli are 0.06 mg/kg then 0.3 mg/kg. The regular once-weekly treatment dose is 1.5 mg/kg given until disease progression or unacceptable side effects. Prior to each dose of the Tecvayli step-up dosing schedule, patients are given pretreatment medications. The step-up dosing schedules include step-up dose 1, step-up dose 2, and the first treatment dose. 

Table 1: Tecvayli dosing schedule

Dosing Schedule Day Dose Dose
Step-Up Dosing Schedule 1 Step-up Dose 1 0.06 mg/kg
Step-Up Dosing Schedule 4b Step-up Dose 2 0.03 mg/kg
Step-Up Dosing Schedule 7c First treatment dose 1.5 mg/kg
Weekly Dosing Schedule One week after first treatment dose and weekly thereafter Subsequent treatment doses 1.5 mg/kg weekly

a. See Table 2 for recommendations on restarting Tecvayli after dose delays.
b. Step-up dose 2 may be given between 2 to 4 days after step-up dose 1 and may be given
up to 7 days after step-up dose 1 to allow for resolution of side effects.
c. First treatment dose may be given between 2 to 4 days after step-up dose 2 and may be given
up to 7 days after step-up dose 2 to allow for resolution of side effects.

Table 2: Restarting therapy with Tecvayli after dose delay

Last dose administered Duration of delay from the last dose Recommendations
Step-up 1 dose More than 7 days Restart Tecvayli step-up dosing schedule
at step-up dose 1 (0.06 mg/kg)a.
Step-up 2 dose 8 days to 28 days Repeat step-up dose 2 (0.3 mg/kg)a and
continue Tecvayli step-up dosing schedule.
Step-up 2 dose More than 28 daysb Restart Tecvayli step-up dosing schedule
at step-up dose 1 (0.06 mg/kg)a.
Any treatment dose 8 days to 28 days Continue Tecvayli weekly dosing schedule
at treatment (1.5 mg/kg).a
Any treatment dose More than 28 daysb Restart Tecvayli step-up dosing schedule
at step-up dose 1 (0.06 mg/kg).a

a. Pretreatment medications are given prior to Tecvayli dose and patients are monitored accordingly.
b. Discuss with your doctor the benefit-risk of restarting Tecvayli if you require a dose delay of more than 28 days due to a side effect.

What Warnings and Precautions Should Patients Undergoing Tecvayli Therapy Be Aware Of? 

The most common side effects occurring in 20% or more patients treated with Tecvayli in the MajesTEC-1 clinical trial were the following: 

  • fever 
  • cytokine release syndrome (CRS) 
  • musculoskeletal pain 
  • injection site reaction
  • fatigue 
  • upper respiratory tract infection 
  • nausea 
  • headache 
  • pneumonia 
  • diarrhea 

The most common severe laboratory abnormalities occurring in 20% or more patients treated with Tecvayli are the following:  

  • decreased lymphocytes 
  • decreased neutrophils 
  • decreased white blood cells 
  • decreased hemoglobin  
  • decreased platelets 

How Is Tecvayli Made Available to Patients? 

Tecvayli is available only through a Risk Evaluation and Mitigation Strategy (REMS) restricted program. The FDA requires a REMS program if a specific drug or treatment has serious safety concerns. REMS programs support the use of such drugs or treatments and help ensure that the potential benefits outweigh the risks. 

What Is Cytokine Release Syndrome (CRS)?

Cytokines are proteins that are produced all over the body, including in the bone marrow. Cytokines circulate in the bloodstream, stimulating or inhibiting the growth and/or activity of other cells. CRS is a potentially fatal, uncontrolled immune reaction in which levels of cytokines become highly elevated and trigger an overwhelming immune system response. A “cytokine storm” can seriously damage body tissues and organs. Learn more at cytokine release syndrome.

Occurrences of CRS in the MajesTEC-1 clinical trial

In the MajesTEC-1 clinical trial of Tecvayli in RRMM, CRS occurred in 72% of patients who received Tecvayli at the recommended dose, with Grade1 CRS occurring in 50% of patients, Grade 2 in 21%, and Grade 3 in 0.6%.

Most patients experienced CRS following step-up dose 1, step-up dose 2, or the first treatment dose.

After subsequent doses of Tecvayli, less than 3% of study participants developed CRS. The median time to onset of CRS was 2 days (range of 1 to 6 days) after the most recent dose, with a median duration of 2 days (range of 1 to 9 days).s. 

Clinical signs and symptoms of CRS included, but were not limited to: 

  • fever 
  • hypoxia 
  • chills 
  • hypotension 
  • sinus tachycardia 
  • headache 
  • elevated liver enzymes 

Conclusions from the Phase I/II MajesTEC-1 clinical trial

At the 2024 American Society of Clinical Oncology (ASCO) annual meeting, conclusions were presented from the phase I/II MajesTEC-1 clinical trial cohort of patients receiving prophylactic tocilizumab (toci) for the reduction of CRS (van de Donk). In patients receiving Tecvayli, the use of prophylactic toci resulted in 65% relative reduction of the overall incidence of CRS. Longer-term follow-up did not reveal new safety concerns or compromise the efficacy of Tecvayli.

Prevention and treatment of CRS

To reduce the risk of CRS, therapy with Tecvayli should be started with the step-up dosing schedule. Pretreatment medications are given to reduce the risk of CRS. Patients are monitored following the administration of Tecvayli. At the first sign of CRS, immediate evaluation should be made to consider the patient for hospitalization. Supportive care is administered based on the severity of CRS. Further management should follow current practice guidelines. Tecvayli administration may be interrupted or discontinued, depending on the severity of the CRS.

What Are Neurological Toxicities That Can Occur with Tecvayli? 

Immune effector cell-associated neurotoxicity syndrome (ICANS) has occurred in patients following treatment with Tecvayli. ICANS often correlates with CRS.  Yet, it can also occur in the absence of CRS. After treatment with Tecvayli, ICANS can occur before, during, or after CRS onset, or after CRS resolution.  

ICANS may be severe, life-threatening, or fatal. Symptoms of neurologic side effects include but are not limited to: 

  • confusion  
  • disorientation 
  • loss of consciousness 
  • seizures 
  • tremor 
  • slower movements 
  • changes in personality 
  • depression 
  • tingling and numbness of hands and feet 
  • leg and arm weakness 
  • facial numbness 
  • difficulty speaking, reading, or writing 

Neurologic toxicity in the MajesTEC-1 clinical trial 

In the MajesTEC-1 clinical trial, neurologic toxicity occurred in 57% of patients who received Tecvayli at the recommended dose, with Grade 3 or 4 neurologic toxicity occurring in 2.4% of patients.  

The most frequent neurologic toxicities were the following: 

  • headache (25%), 
  • motor dysfunction (16%) 
  • sensory neuropathy (15%) 
  • encephalopathy (13%) 

With longer follow-up of patients who received Tecvayli, a Grade 4 seizure occurred in 1 patient, and fatal Guillain-Barré syndrome (GBS) occurred in 1 patient. 

ICANS was reported in 6% of patients who received Tecvayli at the recommended dose. 

Recurrent ICANS occurred in 1.8% of patients.  

Most patients experienced ICANS following step-up dose 1 (1.2%), step-up dose 2 (0.6%), or the initial treatment dose (1.8%). 

Less than 3% of patients developed the first occurrence of ICANS following subsequent doses of Tecvayli. 

The median time to onset of ICANS was 4 days (range of 2 to 8 days) after the most recent dose. The median duration of 3 days (range of 1 to 20 days). 

Prevention and treatment of neurologic toxicities

Patients must be monitored for signs and symptoms of neurologic toxicity during treatment with Tecvayli. At the first sign of neurologic toxicity, including ICANS, patients are provided supportive therapy based on severity, and Tecvayli treatment may also be withheld. 

Patients are advised to refrain from driving or operating heavy or potentially dangerous machinery during and for 48 hours after completion of Tecvayli  step-up dosing schedule and in the event of a new onset of any neurologic toxicity symptoms until neurologic toxicity resolves.

Hepatotoxicity and Tecvyali 

Tecvayli can cause hepatotoxicity. Drug-induced hepatotoxicity is an injury to the liver or an impairment of the liver function caused by exposure to a specific compound. 

In the MajesTEC-1 clinical trial, the following occurred: 

  • 1 fatal case of hepatic failure  
  • Elevation of the liver enzyme aspartate aminotransferase (AST) occurred in 34% of patients, with Grade 3 or 4 elevations in 1.2% 
  • Elevated alanine aminotransferase (ALT) occurred in 28% of patients, with Grade 3 or 4 elevations in 1.8%
  • Elevated total bilirubin occurred in 6% of patients with Grade 3 or 4 elevations in 0.6%  
  • Liver enzyme elevation can occur with or without concurrent CRS

Prevention and treatment of hepatotoxicity

Liver enzymes and bilirubin should be measured at baseline and during treatment as clinically indicated. Tecvayli may be withheld or discontinued based on severity. 

Infections and Tecvayli 

Tecvayli can cause severe, life-threatening, or fatal infections.

In patients who received Tecvayli at the recommended dose in the MajesTEC-1 clinical trial: 

  • serious infections occurred in 30% of patients, with Grade 3 or 4 infections in 35%,  
  • and fatal infections in 4.2%. 

Prevention and treatment of infections

Your doctor needs to monitor you for signs and symptoms of infection before and during treatment with Tecvayli. You must promptly alert your doctor if you experience any infection. Based on the severity of your infection, your doctor may prescribe antibiotics and/or withhold or discontinue Tecvayli. Your immunoglobulin levels should be monitored to assess if you need intravenous immunoglobulin (IVIG) therapy.


Neutropenia is a reduced level of neutrophils, a type of white blood cell necessary to combat bacterial infections. Having too few neutrophils can lead to infection. Fever is the most common sign of neutropenia. If you have a fever, you must get immediate medical attention. 

Tecvayli can cause neutropenia and febrile neutropenia. In patients who received Tecvayli at the recommended dose in the MajesTEC-1 clinical trial, decreased neutrophils occurred in 84% of patients, with Grade 3 or 4 decreased neutrophils in 56%. Febrile neutropenia occurred in 3% of patients.

Prevention and treatment of neutropenia 

Complete blood count (CBC) should be measured at baseline and periodically during treatment. Patients may need growth factors. Signs or symptoms of infections should be discussed with the healthcare team. 

Hypersensitivity and other ARR

Tecvayli can cause both systemic and local administration-related reactions (ARR). In the MajesTEC-1 clinical trial, 1.2% of patients who received Tecvayli at the recommended dose experienced systemic ARR (including Grade 1 recurrent fever and Grade 1 swollen tongue), and 35% of patients experienced local ARR (with 30% Grade 1 and 4.8% Grade 2). 

Prevention and treatment of hypersensitivity and other ARRs

Based on the severity of ARR, Tecvayli may be withheld or discontinued.

Embryo-fetal toxicity

Embryo-fetal toxicity is the exposure of an embryo or a fetus to a toxic substance. Females of reproductive potential and males with female partners of reproductive potential should ask the treating doctor if the use of effective contraception is necessary before treatment begins, during treatment, and/or after the last dose of treatment is administered.

We encourage you to read the entire IMF Publication Understanding Tecvayli if you and your healthcare team are considering this therapy. 


The International Myeloma Foundation medical and editorial content team

Comprised of leading medical researchers, hematologists, oncologists, oncology-certified nurses, medical editors, and medical journalists, our team has extensive knowledge of the multiple myeloma treatment and care landscape.

Additionally, the content on this page is medically reviewed by myeloma physicians and healthcare professionals.   

Last Medical Content Review: May 31, 2024

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