What are the indications and dosing guidelines for Rituxan (rituximab)?

From the Guidelines

Rituximab (Rituxan) is indicated for several conditions including non-Hodgkin's lymphoma, chronic lymphocytic leukemia, rheumatoid arthritis, granulomatosis with polyangiitis, microscopic polyangiitis, and pemphigus vulgaris, with dosing guidelines varying by condition, and it is essential to follow the most recent and highest quality study guidelines for optimal treatment outcomes.

Indications and Dosing Guidelines

• For non-Hodgkin's lymphoma, the typical dose is 375 mg/m² given intravenously, with the standard treatment schedule involving eight infusions of rituximab, as recommended by the most recent study 1.
• For chronic lymphocytic leukemia, it's given at 375 mg/m² for the first cycle, then 500 mg/m² for subsequent cycles, in combination with chemotherapy.
• In rheumatoid arthritis, rituximab is administered as two 1000 mg IV infusions separated by two weeks, with repeat courses possible after 24 weeks.
• For vasculitis conditions, the dose is typically 375 mg/m² weekly for 4 weeks, while pemphigus vulgaris requires 1000 mg initially, followed by another 1000 mg two weeks later, with maintenance doses of 500 mg at months 12 and 18.

Administration and Monitoring

• The first infusion should be given slowly (50 mg/hour initially) with gradual increases, monitoring for infusion reactions which are most common during the first infusion.
• Premedication with acetaminophen, antihistamines, and sometimes corticosteroids is recommended to reduce infusion reactions.
• Rituximab works by targeting CD20 on B lymphocytes, causing B-cell depletion through various mechanisms including antibody-dependent cellular cytotoxicity and complement-dependent cytotoxicity, which explains its efficacy in B-cell malignancies and autoimmune conditions.

Special Considerations

• In patients with immune thrombocytopenia, rituximab may be used off-label, with a typical dose of 375 mg/m² over 4 consecutive weekly infusions, although the optimal dosing has not been defined 1.
• Vaccination strategies should be considered before initiating rituximab treatment, as it impairs the immune response until 6 months after treatment, and live-attenuated vaccines should be withheld in patients on rituximab 1.

From the FDA Drug Label

The dose for adult and pediatric B-cell NHL is 375 mg/m2 (2. 2). The dose for CLL is 375 mg/m2 in the first cycle and 500 mg/m2 in cycles 2–6, in combination with FC, administered every 28 days (2.3). The dose as a component of Zevalin® (ibritumomab tiuxetan) Therapeutic Regimen is 250 mg/m2 (2. 4). The dose for RA in combination with methotrexate is two-1,000 mg intravenous infusions separated by 2 weeks (one course) every 24 weeks or based on clinical evaluation, but not sooner than every 16 weeks. The induction dose for adult patients with active GPA and MPA in combination with glucocorticoids is 375 mg/m2 once weekly for 4 weeks The dose for PV is two-1,000 mg intravenous infusions separated by 2 weeks in combination with a tapering course of glucocorticoids, then a 500 mg intravenous infusion at Month 12 and every 6 months thereafter or based on clinical evaluation.

The indications for Rituxan (rituximab) are:

• Non-Hodgkin's Lymphoma (NHL)
• Chronic Lymphocytic Leukemia (CLL)
• Rheumatoid Arthritis (RA)
• Granulomatosis with Polyangiitis (GPA)
• Microscopic Polyangiitis (MPA)
• Pemphigus Vulgaris (PV)

The dosing guidelines for Rituxan (rituximab) are:

• NHL: 375 mg/m2
• CLL: 375 mg/m2 in the first cycle and 500 mg/m2 in cycles 2–6
• RA: two-1,000 mg intravenous infusions separated by 2 weeks
• GPA and MPA: 375 mg/m2 once weekly for 4 weeks
• PV: two-1,000 mg intravenous infusions separated by 2 weeks, then a 500 mg intravenous infusion at Month 12 and every 6 months thereafter 2, 2

From the Research

Indications for Rituxan (Rituximab)

• Rituximab is approved for the treatment of relapsed or refractory, CD20-positive, B-cell, low-grade or follicular non-Hodgkin's lymphoma (NHL) 3, 4.
• It is also approved for the treatment of rheumatoid arthritis (RA) that does not respond adequately to disease-modifying antirheumatic drugs, including anti-tumor-necrosis-factor (TNF) biologics 5.
• Rituximab has shown efficacy in patients with indolent and aggressive forms of B-cell NHL, as well as B-cell chronic lymphocytic leukemia (CLL) 6, 7.

Dosing Guidelines for Rituxan (Rituximab)

• The recommended dose of rituximab is 375 mg/m2 intravenously weekly for 4 infusions 6, 4.
• For patients with rheumatoid arthritis, the dose is 1000 mg intravenously on days 1 and 15, with optional subsequent courses given at 24-week intervals 5.
• The optimal dose and retreatment schedule of rituximab in RA remains to be established, but sustained efficacy can be achieved by repeated courses of rituximab 5.

Administration and Safety

• Rituximab is generally well tolerated, with mostly grade 1 and 2 adverse events occurring primarily with the first infusion 6, 4.
• Infusion-related reactions occur in the majority of patients, but are usually mild to moderate and decrease in frequency with subsequent infusions 6.
• Serious infections, including opportunistic infections, can occur with rituximab treatment, and screening for baseline serum immunoglobulin G level and hepatitis B status is important 5.