bDMARDs Quick Reference Guide

Rituximab

HomeMonographsRituximab

Active ingredient

Rituximab

Mechanism of action

B cell inhibitor (CD20)

Molecule type

IgG monoclonal antibody (chimeric)

PBS listed indications

Severe active rheumatoid arthritis

Severe active granulomatosis with polyangiitis (Wegeners granulomatosis)*

Severe active microscopic polyangiitis*

 

* Ritxuimab use in the oncology setting and for ANCA-associated vasculitis (granulomatosis with polyangiitis and microscopic polyangiitis) are outside the scope of this guide.

Reference product (brand)

Mabthera (no longer PBS listed)

Biosimilar brands

Riximyo, Truxima

Administration information

Mode of administration

IV infusion

NOTE: Formulations of rituximab for subcutaneous injection are available but are not PBS funded for rheumatoid arthritis.

Administration devices and strengths

Vial for IV infusion 500mg/50mL

100mg/10mL vial also available but not PBS funded for rheumatoid arthritis

 

 

Frequency of administration

Every 2 weeks

Storage

Store at 2-8oC (refrigerate do not freeze).

Keep vials in the outer carton until time of use to protect from light.

Prepared infusion bags may be stored in the refrigerator for up to 24 hours.

Standard dosing

1g for 2 doses given 2 weeks apart

Patients who respond to the initial course will be given subsequent courses of treatment (usually after 6-12 months)

 

Treatment with csDMARDs (e.g., methotrexate) may be continued during treatment with rituximab.

Dose variations

Patients with rheumatoid arthritis who are in remission or have low disease activity may have their dose of rituximab down-titrated by their rheumatologist

  • 1g for one dose (following initial treatment).

Special notes

Premedication consisting of an analgesic/antipyretic such as paracetamol and an antihistamine should always be administered 30-60 minutes before each infusion. Premedication with glucocorticoids should also be administered in order to reduce the frequency and severity of infusion related reactions. Patients should receive a corticosteroid such as 100mg IV methylprednisolone to be completed 30 minutes prior to each rituximab infusion.

 

Consider withholding antihypertensives for 12 hours before and during administration to reduce hypotension.

 

Hepatitis B screening should be performed in all patients before starting treatment with rituximab. Patients with active hepatitis B infection should not be treated with rituximab until hepatitis B treatment has been completed unless otherwise advised.
Patients with inactive hepatitis B or positive serology should be managed in consultation with a liver specialist and may require reactivation prophylaxis with entecavir.

 

Avoid use in serious or untreated infection, e.g. sepsis, active TB (before completing TB treatment). May reactivate latent TB (begin TB treatment before starting rituximab).
Patients with suspected latent or active TB should be treated in consultation with an Infectious Diseases physician.

Avoid use of rituximab in combination with other cytokine modulators (eg TNF-alpha inhibitors, tocilizumab, tofacitinib); as this may increase risk of infection.

 

Monitor patients with heart disease closely; angina, arrhythmias, heart failure and myocardial infarction have occurred with rituximab.

 

Neutropenia (may be delayed onset), lymphopenia and hypogammaglobulinaemia are common (>1%) side effects of rituximab. Regular monitoring of blood counts should be performed in patients receiving rituximab.

 

Use of rituximab may be associated with an increased risk of progressive multifocal leukoencephalopathy (PML), an extremely rare opportunistic viral infection of the brain that can lead to severe disability or death. Patients must be monitored for any new or worsening neurological sign or symptoms suggestive of PML. If symptoms occur, treatment with rituximab should be ceased until a diagnosis of PML has been excluded.

 

Live vaccines should not be given concurrently with rituximab. Rituximab may also impair antibody formation following any vaccination.

References

Pharmaceutical benefits Scheme (PBS) listing. Available from     https://www.pbs.gov.au/pbs/search?term=rituximab&analyse=false&search-type=medicines [accessed 8/10/21]

Product information. Available from     https://www.ebs.tga.gov.au/ebs/picmi/picmirepository.nsf/PICMI?OpenForm&t=&q=rituximab&r=/ [accessed 8/10/21]

Australian Medicines Handbook 2020 (online). Adelaide: Australian Medicines Handbook Pty Ltd; 2020 July. Available from: https://amhonline.amh.net.au/   [accessed 13/5/21]

NPS Medicinewise. Down-titration strategies. Available from https://www.nps.org.au/bdmards/rheumatology-conditions/titration-strategies [accessed 13/5/21]