# Mosunetuzumab against rituximab in low tumour burden follicular lymphoma

Source: https://onco.cc/trials/mosun-lbt-fl/  
OnCo record `mosun-lbt-fl` (Trial). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

A large American trial testing whether a two-headed antibody that recruits the immune system should replace the standard antibody as the first treatment for slow-growing follicular lymphoma.

## Summary

Low tumour burden follicular lymphoma is the setting in which rituximab alone, given as four weekly doses, has been the gentle standard for twenty years, and in which watch and wait remains a reasonable alternative. This National Cancer Institute trial asks whether mosunetuzumab, a CD20 by CD3 bispecific antibody given for a fixed duration, does better.

It is among the first phase 3 trials to put a bispecific antibody against rituximab in a first-line, low-burden population; the class has so far been tested almost entirely in relapsed disease. Participants are randomised between rituximab (with the hyaluronidase subcutaneous formulation permitted) and mosunetuzumab. The co-primary endpoints are three-year progression-free survival and progression-free survival overall, with primary completion estimated for 31 March 2032.

What makes it worth watching is the question underneath it: whether a treatment that produces deep remissions in heavily pretreated disease changes the natural history when it is given first, or simply moves the same remission earlier. The answer bears on every indolent lymphoma.

## Fields

- Kind: Trial
- Status: active
- Last checked: 2026-10-01
- Also known as: Rituximab versus mosunetuzumab in low tumour burden follicular lymphoma
- Tags: lymphoma-evidence
- Registry id: NCT06337318
- Phase: 3
- Setting: Follicular lymphoma with a low tumour burden needing first treatment: four weekly doses of rituximab against fixed-duration mosunetuzumab
- Sponsor: National Cancer Institute
- Enrolled: 600

## Sources

- ClinicalTrials.gov NCT06337318: https://clinicaltrials.gov/study/NCT06337318

## Connected records

- cancers: [Follicular lymphoma](https://onco.cc/cancers/follicular-lymphoma/), [Non-Hodgkin lymphoma (all types)](https://onco.cc/cancers/non-hodgkin-lymphoma/)
- fronts: [Immunotherapy](https://onco.cc/fronts/immunotherapy/)
- technologies: [Bispecific antibodies](https://onco.cc/technologies/bispecific-antibody/), [Monoclonal antibodies](https://onco.cc/technologies/monoclonal-antibody/), [T-cell engagers (bispecific)](https://onco.cc/technologies/t-cell-engager/)
- targets: [CD20](https://onco.cc/targets/cd20/), [CD3](https://onco.cc/targets/cd3/)
- drugs: [Mosunetuzumab](https://onco.cc/drugs/mosunetuzumab/), [Rituximab](https://onco.cc/drugs/rituximab/)
- institutions: [National Cancer Institute (NIH)](https://onco.cc/institutions/nci/)
- terms: [FLIPI, FLIPI2 and POD24 (follicular lymphoma risk)](https://onco.cc/terms/flipi/), [Watch and wait in lymphoma: when the right treatment is none yet](https://onco.cc/terms/lymphoma-tx-watch-and-wait/), [Watchful waiting, and how it differs from active surveillance](https://onco.cc/terms/watchful-waiting/)
- bottlenecks: [Prices and value](https://onco.cc/bottlenecks/b-drug-pricing/), [Trial design, endpoints and cost](https://onco.cc/bottlenecks/b-trial-design/)
- roadmaps: [Lymphoma roadmap: from a jaw tumour in Uganda and the first human cancer virus to gene-expression subtypes, PET-adapted chemotherapy, CAR-T cells, bispecific antibodies and the genetics-directed trials now recruiting](https://onco.cc/roadmaps/lymphoma-roadmap/)
- ideas: [Fixed-duration, chemotherapy-free first-line treatment for the indolent lymphomas](https://onco.cc/ideas/lymphoma-ev-fixed-duration-chemotherapy-free-first-line/)

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