ClinCalc Pro
Menu
Calculators Drugs Pathways AI Dx Donate Get the App
CD20×CD3 Bispecific T-Cell Engager Pregnancy: Contraindicated — insufficient data; effective contraception during and for 3 months after treatment

Mosunetuzumab

Brand names: Lunsumio

Adult dose

Dose: Cycle 1: 1 mg (D1), 2 mg (D8), 60 mg (D15); Cycles 2+: 30 mg D1; Cycle 3 onwards if CR: 30 mg D1 for up to 8 cycles total
Route: Intravenous infusion
Frequency: Every 21 days (step-up dosing cycle 1 to reduce CRS)
Max: 60 mg per dose
Relapsed/refractory follicular lymphoma ≥2 prior lines; fixed-duration treatment (up to 17 cycles)

Paediatric dose

Dose: Not established N/A/kg
Route: N/A
Frequency: N/A
Max: N/A
Not licensed in paediatrics

Dose adjustments

Renal

No formal adjustment; limited data in severe renal impairment

Hepatic

No formal adjustment required for mild-moderate impairment; limited data in severe

Paediatric weight-based calculator

Not licensed in paediatrics

Clinical pearls

  • CELESTIMO trial (Budde et al. Lancet 2022): 80% overall response rate in heavily pre-treated R/R follicular lymphoma, with 60% complete responses — a landmark result for an off-the-shelf bispecific
  • MHRA 2023 approved; NICE TA900 for R/R follicular lymphoma ≥2 prior lines; first CD20×CD3 bispecific with NICE approval for fixed-duration monotherapy
  • Step-up dosing protocol in cycle 1 (1→2→60 mg) is mandatory to reduce CRS severity — hospitalisation required for cycle 1, day 1 and day 8 doses
  • Cytokine release syndrome is managed with tocilizumab (anti-IL-6) + corticosteroids; tocilizumab must be available before infusion — centres need CRS management protocols
  • Unlike CAR-T, mosunetuzumab is off-the-shelf and administered outpatient after cycle 1 safety assessment — represents a step-change in accessibility of bispecific therapy

Contraindications

  • Active autoimmune conditions requiring systemic immunosuppression
  • Known hypersensitivity

Side effects

  • Cytokine release syndrome (CRS — mostly grade 1-2, step-up dosing mitigates)
  • Immune effector cell-associated neurotoxicity (ICANS)
  • Neutropenia
  • Fatigue
  • Pyrexia
  • Infections

Interactions

  • Corticosteroids — used to treat CRS; avoid prophylactic use as may reduce efficacy
  • Live vaccines — avoid; immune suppression from T-cell redirection
  • Immunosuppressants — additive immunosuppression

Monitoring

  • Vital signs and CRS grading during each infusion
  • Neurological assessment (ICANS)
  • FBC
  • CRP/ferritin (CRS markers)
  • Infection surveillance
  • Tumour lysis monitoring (cycle 1)

Reference: BNFc; BNF 90; CELESTIMO trial (Budde et al. Lancet 2022); NICE TA900; MHRA SPC Lunsumio; GO29781 trial (Budde et al. JCO 2022). Verify against your local formulary and the latest BNF before prescribing.

Related

Curated clinical cross-links plus same-class fallbacks.

Calculators
Pathways