Mosunetuzumab (Specialist drug)

How it works

It is a CD20-directed CD3 T-cell engager that bridges malignant CD20-positive B cells to CD3-positive T cells, redirecting T-cell cytotoxicity against the lymphoma cells.

Prescribing in practice

• Cytokine release syndrome is a key risk, particularly with early doses, so step-up dosing, premedication and close monitoring for fever, hypotension and hypoxia are essential.
• Neurological toxicity, serious infections and tumour flare can occur, and the step-up dosing schedule must be followed exactly as in the SPC.
• Patients require appropriate infection prophylaxis and management of cytopenias during therapy.

Monitoring

Monitor closely for cytokine release and neurological symptoms during and after infusions, alongside full blood count and signs of infection.

Counselling the patient

• Report fever, chills, dizziness, confusion or breathlessness without delay, especially in the early cycles.
• Attend all monitoring appointments and the planned step-up dosing visits.
• Tell the team about any signs of infection between treatments.

Evidence & guidelines

Mosunetuzumab is approved for relapsed or refractory follicular lymphoma and has been appraised by NICE for use within specialist haemato-oncology services.