BCMA×CD3 Bispecific Antibody Pregnancy: May cause fetal harm when administered to a pregnant patient, based on the mechanism of action. There are no available data in pregnant patients and no animal reproductive or developmental toxicity studies. Teclistamab causes T-cell activation and cytokine release, and immune activation may compromise pregnancy maintenance; human IgG crosses the placenta so teclistamab may be transmitted to the developing fetus. Teclistamab is associated with hypogammaglobulinaemia, so assessment of immunoglobulin levels in newborns of treated mothers should be considered. Advise females of reproductive potential of the risk to the fetus and to use effective contraception.

Teclistamab

Brand names: Tecvayli

Teclistamab is a BCMA x CD3 bispecific T-cell engaging antibody used for relapsed or refractory multiple myeloma after multiple prior lines of therapy.

Auto-extracted from the source labelling — not yet independently clinician-verified. These values were distilled from the UK SPC (or the US label where noted) but have not had a clinician sign-off. Confirm against the current SmPC before prescribing.

Adult dose

Dose: Step-up dosing schedule followed by treatment dosing (monotherapy): step-up dose 1 = 0.06 mg/kg on Day 1; step-up dose 2 = 0.3 mg/kg on Day 4; first treatment dose = 1.5 mg/kg on Day 7; then subsequent treatment doses of 1.5 mg/kg once weekly.

Route: Subcutaneous injection only

Frequency: Monotherapy: step-up doses on Days 1, 4 and 7 as above, then 1.5 mg/kg once weekly starting one week after the first treatment dose — maintain a minimum of 5 days between weekly doses. In patients who have achieved and maintained a complete response or better for a minimum of 6 months, the frequency may be decreased to 1.5 mg/kg every two weeks (minimum 12 days between doses). Continue until disease progression or unacceptable toxicity.

SOURCE: US FDA prescribing information (TECVAYLI, Janssen Biotech, label date 2026-03-10) via openFDA/DailyMed — NO UK SPC was present in the fetched bundle; clinician to cross-check against the UK SPC. SAFETY (CRS/ICANS): because of the risk of cytokine release syndrome and neurologic toxicity including ICANS, patients should be hospitalised for 48 hours after administration of BOTH step-up dose 1 and step-up dose 2, and should be instructed to remain within proximity of a healthcare facility and be monitored daily for 48 hours after the first treatment dose. Administer pretreatment medications 1 to 3 hours before each dose of the step-up dosing schedule (step-up dose 1, step-up dose 2 and the first treatment dose) to reduce the risk of CRS. Step-up dose 2 may be given between 2 and 4 days after step-up dose 1 (up to 7 days after, if adverse reactions need time to resolve); the first treatment dose may be given between 2 and 4 days after step-up dose 2 (up to 7 days after, if needed). COMBINATION WITH SUBCUTANEOUS DARATUMUMAB AND HYALURONIDASE-FIHJ: Day 0 daratumumab and hyaluronidase-fihj; Day 1 step-up dose 1 0.06 mg/kg (must be given 20 hours or more after the daratumumab and hyaluronidase-fihj dose); Day 3 step-up dose 2 0.3 mg/kg; Day 7 first treatment dose 1.5 mg/kg (give teclistamab at least 3 hours after the daratumumab and hyaluronidase-fihj dose for the first treatment dose, and at least 15 minutes after it for subsequent doses); Weeks 2 to 8 — 1.5 mg/kg once weekly (minimum 5 days between doses); Weeks 9 to 24 — 3 mg/kg every two weeks (minimum 12 days between doses); Week 25 onwards — 3 mg/kg every four weeks (minimum 25 days between doses). The step-up dosing schedule is a component of the teclistamab dosage only and is not applicable to the daratumumab and hyaluronidase-fihj dosing. PREPARATION: refer to label Tables 8, 9, 10 and 11 to determine the total dose, injection volume and number of vials based on the patient's body weight. Product strengths: 30 mg/3 mL (10 mg/mL) and 153 mg/1.7 mL (90 mg/mL) single-dose vials. Recommendations for restarting after dose delays are in label Table 3.

Dose auto-extracted from US FDA prescribing information (openFDA / DailyMed) — cross-check; US labelling may differ from UK — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.

Contraindications

None (US label §4 states: None)

Side effects

Cytokine release syndrome — occurred in 64% of patients across the monotherapy and combination trials (N=448); can be life-threatening or fatal
Neurologic toxicity including ICANS
Infections — severe, life-threatening or fatal infections; upper respiratory tract infection, pneumonia, COVID-19 and gastroenteritis were among the most common reactions; hypogammaglobulinaemia (most common reaction with the daratumumab combination)
Neutropenia and other cytopenias — the most common Grade 3 to 4 laboratory abnormalities are decreased lymphocytes, decreased neutrophils, decreased white blood cells and decreased haemoglobin
Pyrexia, fatigue, musculoskeletal pain, headache and injection site reactions
Hepatotoxicity, including fatalities — monitor liver enzymes and bilirubin at baseline and during treatment; also nausea, diarrhoea and cough

Interactions

CYP substrates — teclistamab causes cytokine release that may suppress the activity of certain cytochrome P450 enzymes, increasing exposure to CYP substrates and the risk of their adverse reactions. The highest risk is from initiation of the step-up dosing schedule up to 7 days after the first treatment dose, and during and after CRS. Monitor for toxicity and/or concentrations of CYP substrates where minimal increases in concentration may lead to serious adverse reactions, and consider decreasing the dose of the concomitant CYP substrate as needed

Clinical monograph

How it works

It bridges BCMA on myeloma cells to CD3 on T-cells, redirecting T-cell-mediated cytotoxicity to kill malignant plasma cells.

Prescribing in practice

Carries a significant risk of cytokine release syndrome and neurological toxicity including ICANS, so step-up dosing, premedication, and administration with monitoring and resuscitation facilities available are mandatory.
Causes serious infections and marked, sometimes prolonged neutropenia and hypogammaglobulinaemia; infection prophylaxis and immunoglobulin support may be needed.
Initiation and step-up dosing should occur where patients can be observed for the recommended period, and patients should avoid driving during the relevant window because of neurological risk.

Monitoring

Monitor for cytokine release syndrome and neurological symptoms during step-up dosing, and check full blood count and for signs of infection regularly.

Counselling the patient

Seek urgent help for fever, confusion, severe headache, or difficulty speaking.
Report any signs of infection promptly, as the immune system may be weakened.
Do not drive or operate machinery during the period advised after each step-up dose.

Evidence & guidelines

Teclistamab's efficacy in heavily pretreated myeloma was demonstrated in the MajesTEC-1 study, supporting its licensed indication.

Reference: MajesTEC-1 trial (Moreau et al. NEJM 2022); MHRA SPC Tecvayli 2022; NICE TA898; MajesTEC-4 trial ongoing; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Curated clinical cross-links plus same-class fallbacks.

Drugs

Elranatamab · BCMA×CD3 Bispecific Antibody

Pathways