Rituximab

Indications

Rituximab is used for: Non-Hodgkin's lymphoma; follicular lymphoma

Adult Dose

Intravenous Non-Hodgkin Lymphoma Recommended dose for NHL 375 mg/m² IV infusion according to the following schedules Relapsed or refractory low-grade or follicular, CD20-positive, B-cell NHL: Once weekly x4-8 doses Retreatment for relapsed or refractory, low-grade or follicular, CD20-positive, B-cell NHL: Once weekly x4 doses Previously untreated, follicular, CD20-positive, B-cell NHL: Administer on Day 1 of each chemotherapy cycle for up to 8 doses; with complete or partial response, initiate maintenance 8 weeks following completion of combination chemotherapy as a single-agent q8weeks for 12 doses Nonprogressing, low-grade, CD20-positive, B-cell NHL, after first-line CVP chemotherapy: Following completion of 6-8 cycles of CVP chemotherapy, administer once weekly for 4 doses at 6-month intervals to a maximum of 16 doses Diffuse large B-cell NHL: Administer on Day 1 of each cycle of chemotherapy for up to 8 infusions Chronic Lymphocytic Leukemia Indicated for untreated and previously treated CD20-positive CLL; combined therapy with fludarabine and cyclophosphamide (FC) 375 mg/m² IV infusion on day 1 of 1st cycle (for 1st cycle, administer 1 day before chemotherapy with FC), THEN 500 mg/m² IV on day 1 of subsequent cycles (administer on same day as chemotherapy with FC) Repeat q28 days x6 cycles Fludarabine & cyclophosphamide dosage Fludarabine: 25 mg/m² IV qDay x 3 days Cyclophosphamide: 250 mg/m² IV qDay x3 days Repeat q28 days x 6 cycles Rheumatoid Arthritis 1000 mg IV infusion, repeat after 2 week (2 infusions separated by 2 week is 1 course) Repeat course q24weeks or based on clinical evaluation (but no sooner than 16 weeks) Used in combo with methotrexate Premedicate with glucocorticoids 30 minutes before infusion to reduce infusion rxn Not to exceed 1000 mg/dose

Child Dose

Safety and efficacy not established

Renal Dose

Administration

Reconstitution: Dilute the appropriate dose w/ sodium chloride 0.9% or glucose 5% to a final concentration of between 1 and 4 mg/mL. IV Administration Consider premedication (ie, paracetamol and diphenhydramine, or glucocorticoids for RA) before each infusion Administer by slow IV infusion only; do not administer as an IV First IV infusion rate: Start 50 mg/hr; increase by 50 mg/hr q30min, not to exceed 400 mg/hr Subsequent IV infusions (90 minutes) Standard IV infusions: Start 100 mg/hr, increase by 100 mg/hr q30min, not to exceed 400 mg/hr; institutional protocols may allow faster increments

Contra Indications

Lactation. Type I hypersensitivity or anaphylactic reactions to murine proteins or component of the formulation.

Precautions

Extensive tumor burden, pulmonary tumor infiltration or pulmonary insufficiency; history of cardiac disease; effective contraception during and up to 12 mth after treatment; pregnancy. Monitor CBC and platelet counts regularly. Premedication with analgesics, antihistamines and corticosteroids may be recommended. Monitor for signs of active infection or hepatitis in hepatitis B carriers. Discontinue treatment if viral hepatitis develops. Lactation: not known if excreted in breast milk, do not nurse

Pregnancy-Lactation

Pregnancy Limited available data in pregnant women are insufficient to inform a drug-associated risk of adverse developmental outcomes Use with caution in pregnant patients because of the potential for pregnancy related hemorrhage and/or emergent delivery; anticoagulant effect cannot be reliably monitored with standard laboratory testing Consider benefits and risks for the mother and possible risks to the fetus when prescribing to a pregnant woman Females of reproductive potential requiring anticoagulation should discuss pregnancy planning Clinical considerations Pregnancy is a risk factor for VTE and risk increases in women with inherited or acquired thrombophilias; pregnant women with thromboembolic disease have an increased risk of maternal complications (eg, pre-eclampsia); maternal thromboembolic disease increases the risk for intrauterine growth restriction, placental abruption, and early and late pregnancy loss Based on pharmacologic activity of Factor Xa inhibitors and the potential to cross the placenta, bleeding may occur at any site in the fetus and/or neonate All patients receiving anticoagulants, including pregnant women, are at risk for bleeding and this risk may be increased during labor or delivery; risk of bleeding should be balanced with the risk of thrombotic events when considering the use in this setting Lactation Drug detected in human milk Insufficient data available to determine effects on breastfed child or on milk production; drug and/or its metabolites were present in milk of rats Consider developmental and health benefits of breastfeeding along with mother’s clinical need for therapy and any potential adverse effects on breastfed infant from therapy or from underlying maternal condition

Interactions

Increased risk of renal toxicity w/ cisplatin. Potentially Fatal: May decrease the efficacy of vaccines and increase the risk of infections in patients immunised w/ live vaccines.

Adverse Effects

Side effects of Rituximab : >10% NHL Angioedema (11%), hypotension (10%), Asthenia (26%), chills (33%), dizziness (10%), fever (53%), headache (19%) Pruritus (14%), rash (15%), Abdominal pain (14%), diarrhea (10%), nausea (23%), vomiting (10%) Leukopenia (14%), lymphopenia (48%), neutropenia (14%), thrombocytopenia (12%), Back pain (10%), myalgia (10%) Cough (13%), rhinitis (12%), Infection (31%), night sweats (15%) 1-10% NHL Edema, Flushing, Hypertension, Anxiety, Anemia, Elevated LDH, Hyperglycemia, Bronchospasm, dyspnea, sinusitis, throat irritation, urticaria, RA (Rituximab+Methotrexate vs Methotrexate Alone) Hypertension, Anxiety, asthenia, chills, migraine, paresthesia, pyrexia, Pruritus, urticaria, Dyspepsia, nausea, upper abd pain, Hypercholesterolemia, Arthralgia, Rhinitis, throat irritation, URI Frequency Not Defined Tumor lysis syndrome, Lymphoid malignancies, Hypogammaglobulinemia Potentially Fatal: Pulmonary or cardiac toxicity during infusion; severe mucocutaneous reactions; severe cytokine release syndrome associated with tumor lysis syndrome. Toxic epidermal necrolysis.

Mechanism of Action

Rituximab is a chimeric monoclonal antibody to CD20 antigen which regulates cell cycle initiation. It binds to the antigen on the cell surface, activating complement-dependent B-cell cytotoxicity; and to human Fc receptors, mediating cell killing through an antibody-dependent cellular toxicity.