Obinutuzumab (Specialist drug)

How it works

It binds the CD20 antigen on B cells and causes potent B-cell depletion mainly via direct cell death and antibody-dependent cellular cytotoxicity/phagocytosis, with relatively less complement-dependent cytotoxicity than rituximab.

Prescribing in practice

• Screen for hepatitis B before treatment, as B-cell depletion can cause hepatitis B reactivation that may be fatal — do not start without checking serology and arranging appropriate prophylaxis and monitoring.
• Tumour lysis syndrome and severe infusion-related reactions can occur, especially with the first infusion and high tumour burden, so use premedication, hydration and close monitoring.
• Neutropenia and infection are common, and rare progressive multifocal leukoencephalopathy has been reported, warranting prompt assessment of new neurological symptoms.

Monitoring

Monitor full blood count, signs of infection, infusion reactions and biochemical markers of tumour lysis, and stay alert to hepatitis B reactivation and neurological changes during and after therapy.

Counselling the patient

• Report any fever or signs of infection straight away.
• Tell us about new neurological symptoms such as confusion or vision change.
• Avoid live vaccines during and for some time after treatment.

Evidence & guidelines

Its haematological indications are established through pivotal randomised trials demonstrating improved progression-free survival when combined with chemotherapy.