# CD20 bispecific antibodies: step-up dosing, fixed duration and what it is like to take one

Source: https://onco.cc/terms/lymphoma-tx-bispecific-step-up/  
OnCo record `lymphoma-tx-bispecific-step-up` (Term). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Bispecific antibodies grab a lymphoma cell with one arm and a T cell with the other. The first doses are deliberately tiny because the first full dose is what causes fever and low blood pressure; after that most people take them as an outpatient.

## Summary

Four are in use in lymphoma. Glofitamab (intravenous, for large B-cell lymphoma after two lines) is given for a fixed twelve cycles and then stopped, after a dose of obinutuzumab seven days before the first dose to reduce cytokine release syndrome, and step-up doses of 2.5 mg and 10 mg before the 30 mg target. Epcoritamab (subcutaneous) is given weekly then fortnightly then monthly until progression, with a priming dose and an intermediate dose in cycle 1. Mosunetuzumab (intravenous) is given in 21-day cycles with cycle-1 step-up of 1 mg, 2 mg then 60 mg, for eight cycles if a complete response is reached and up to seventeen otherwise. Odronextamab (intravenous) uses a 0.7/4/20 mg split step-up that reduced grade 3 or worse cytokine release syndrome to 1.7 per cent in the follicular cohort of ELM-2.

What it is like. The first cycle usually needs an overnight stay or close observation; fever, chills and a fall in blood pressure in the 24 hours after a step-up dose are common and are managed with paracetamol, fluids, steroids and, if needed, tocilizumab. Neurological events are less frequent than with CAR-T but are looked for at every visit. After cycle 1 to 2 most people attend as outpatients. Infections, and low immunoglobulin levels that persist for months, are the main long-term problem.

Why fixed duration matters. Glofitamab and mosunetuzumab stop at a set point, which is unusual in lymphoma and means a person can finish. Epcoritamab is given until progression. That difference, not the response rate, is often what decides which one someone wants.

## Fields

- Kind: Term
- Last checked: 2026-09-29
- Also known as: Step-up dosing; T-cell engager lymphoma; Glofitamab schedule; Epcoritamab schedule; Mosunetuzumab schedule

## Sources

- Epcoritamab dose expansion in relapsed large B-cell lymphoma, Journal of Clinical Oncology 2023: https://doi.org/10.1200/JCO.22.01725
- Mosunetuzumab in relapsed or refractory follicular lymphoma, Lancet Oncology 2022 (complete response 60.0 per cent): https://doi.org/10.1016/S1470-2045(22)00335-7
- Odronextamab in relapsed or refractory follicular lymphoma, ELM-2, Annals of Oncology 2024: https://doi.org/10.1016/j.annonc.2024.08.2239

## Connected records

- cancers: [Diffuse large B-cell lymphoma](https://onco.cc/cancers/dlbcl/), [Follicular lymphoma](https://onco.cc/cancers/follicular-lymphoma/), [Marginal zone lymphoma](https://onco.cc/cancers/marginal-zone-lymphoma/), [Non-Hodgkin lymphoma (all types)](https://onco.cc/cancers/non-hodgkin-lymphoma/)
- technologies: [Bispecific antibodies](https://onco.cc/technologies/bispecific-antibody/)
- drugs: [Epcoritamab](https://onco.cc/drugs/epcoritamab/), [Glofitamab](https://onco.cc/drugs/glofitamab/), [Mosunetuzumab](https://onco.cc/drugs/mosunetuzumab/), [Obinutuzumab](https://onco.cc/drugs/obinutuzumab/), [Odronextamab](https://onco.cc/drugs/odronextamab/), [Tocilizumab](https://onco.cc/drugs/tocilizumab/)
- terms: [Cytokine release syndrome (CRS)](https://onco.cc/terms/crs/), [Cytokine release syndrome and ICANS: grading and management](https://onco.cc/terms/lymphoma-tx-crs-icans/), [ICANS (neurotoxicity)](https://onco.cc/terms/icans/), [Immunoglobulin replacement after CAR-T, bispecifics and long anti-CD20 treatment](https://onco.cc/terms/lymphoma-tx-immunoglobulin-replacement/)
- trials: [EPCORE DLBCL-1](https://onco.cc/trials/epcore-dlbcl-1/), [EPCORE NHL-1](https://onco.cc/trials/epcore-nhl-1/), [STARGLO](https://onco.cc/trials/starglo/), [SUNMO](https://onco.cc/trials/sunmo/)

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