- Home
- Medical news & Guidelines
- Anesthesiology
- Cardiology and CTVS
- Critical Care
- Dentistry
- Dermatology
- Diabetes and Endocrinology
- ENT
- Gastroenterology
- Medicine
- Nephrology
- Neurology
- Obstretics-Gynaecology
- Oncology
- Ophthalmology
- Orthopaedics
- Pediatrics-Neonatology
- Psychiatry
- Pulmonology
- Radiology
- Surgery
- Urology
- Laboratory Medicine
- Diet
- Nursing
- Paramedical
- Physiotherapy
- Health news
- Fact Check
- Bone Health Fact Check
- Brain Health Fact Check
- Cancer Related Fact Check
- Child Care Fact Check
- Dental and oral health fact check
- Diabetes and metabolic health fact check
- Diet and Nutrition Fact Check
- Eye and ENT Care Fact Check
- Fitness fact check
- Gut health fact check
- Heart health fact check
- Kidney health fact check
- Medical education fact check
- Men's health fact check
- Respiratory fact check
- Skin and hair care fact check
- Vaccine and Immunization fact check
- Women's health fact check
- AYUSH
- State News
- Andaman and Nicobar Islands
- Andhra Pradesh
- Arunachal Pradesh
- Assam
- Bihar
- Chandigarh
- Chattisgarh
- Dadra and Nagar Haveli
- Daman and Diu
- Delhi
- Goa
- Gujarat
- Haryana
- Himachal Pradesh
- Jammu & Kashmir
- Jharkhand
- Karnataka
- Kerala
- Ladakh
- Lakshadweep
- Madhya Pradesh
- Maharashtra
- Manipur
- Meghalaya
- Mizoram
- Nagaland
- Odisha
- Puducherry
- Punjab
- Rajasthan
- Sikkim
- Tamil Nadu
- Telangana
- Tripura
- Uttar Pradesh
- Uttrakhand
- West Bengal
- Medical Education
- Industry
Rituximab
Indications, Uses, Dosage, Drugs Interactions, Side effects
Rituximab
Drug Related WarningRituximab
SEVERE MUCOCUTANEOUS REACTIONS, PROGRESSIVE MULTIFOCAL LEUKOENCEPHALOPATHY, FATAL INFUSION REACTIONS, and TUMOR LYSIS SYNDROME (TLS)
• Around 80% of fatal infusion reactions occurred with the first infusion; these reactions arise within 24 hours of the Rituximab infusion. In the event of severe reactions, monitor patients and stop the Rituximab infusion.
• Syndromes of tumor lysis.
• Serious mucocutaneous reactions, some of which result in death.
• PML that causes death
Medicine Type :
Allopathy
Allopathy
Prescription Type:
Prescription Required
Prescription Required
Approval :
DCGI (Drugs Controller General of India)
DCGI (Drugs Controller General of India)
Schedule
Schedule H
Schedule H
Pharmacological Class:
Monoclonal antibodies, CD20 inhibitors, Therapy Class:
Antineoplastic agent, Approved Countries
India, the United States, Canada, countries within the European Union, Australia, Japan and South Korea.
Rituximab is an antineoplastic agent belonging to the pharmacological class of monoclonal antibodies.
Rituximab is FDA-approved for treating various conditions, including non-Hodgkin's lymphoma, chronic lymphocytic leukaemia, granulomatosis with polyangiitis, rheumatoid arthritis, and microscopic polyangiitis.
When injected intravenously, Rituximab enters the bloodstream directly. It is distributed throughout the body's compartments, particularly the extracellular and blood spaces. Rituximab binds to CD20 antigen-presenting cells and depletes B cells without going through the normal metabolic process. With a variable half-life, elimination occurs through renal excretion and reticuloendothelial clearance.
The most common side effects of Rituximab include headache, weakness, oedema, infection, and hair loss.
Rituximab is available as an injectable solution (single-dose vials).
The molecule is available in India, the United States, Canada, countries within the European Union, Australia, Japan and South Korea.
Rituximab is an antineoplastic agent belonging to the pharmacological class of monoclonal antibodies.
The monoclonal antibody rituximab targets the CD20 antigen, which is present in B-lymphocytes, including pre-B and mature cells. CD19, CD20, and CD22 are highly expressed in about 85% of non-Hodgkin's lymphoma (NHL) cases, impacting apoptosis, calcium signalling, and cell cycle regulation. Rituximab triggers cell lysis by focusing on CD20, sparing non-CD20 surface cells, potentially through complement-dependent cytotoxicity (CDC) and antibody-dependent cell-mediated cytotoxicity (ADCC) mechanisms. Comprising a human constant region (Fc) and a murine variable region (Fab), Rituximab is an immunoglobulin G1 (IgG1) antibody subclass, designed explicitly for CD20 with its Fab region, leading to B-lymphocyte depletion due to Fc interaction with immune receptors.
B-cells are implicated in the pathophysiology of rheumatoid arthritis (RA) and chronic synovitis, contributing to autoantibody synthesis, T-cell activation, and cytokine release. Rituximab's administration for RA has significantly improved clinical outcomes. It's also recommended for granulomatosis with polyangiitis (GPA) and microscopic polyangiitis (MPA), conditions characterized by elevated B-cell activity and circulating antineutrophil cytoplasmic antibodies. Studies suggest a faster response to rituximab depletion of CD20+ B-cells in patients with high Fc receptor-like 5 (FCRL5) levels and GPA or MPA.
The peak plasma concentration for rituximab administration varies from 157 mcg/mL after the first infusion, 183 mcg/mL after the second infusion, 318 mcg/mL for a double dose of 500 mg, and 381 mcg/mL for a double dose of 1000 mg.
The onset of B-cell depletion occurs within 3 weeks for non-Hodgkin's lymphomas and within 2 weeks for rheumatoid arthritis.
B-cell depletion spans approximately 6-9 months for non-Hodgkin's lymphomas and around 6 months for rheumatoid arthritis.
Rituximab is available as an injection solution.
Injection solutions: To be administered parenterally as applicable.
To help lessen side effects like fever and chills, the physician should prescribe additional medications (like methylprednisolone, acetaminophen, and an antihistamine) for you to take prior to each treatment.
- Non-Hodgkin lymphoma (NHL)
- Rheumatoid arthritis
- Blood cancer (Chronic lymphocytic leukaemia)
- Granulomatosis with polyangiitis
- Microscopic polyangiitis
- Pemphigus Vulgaris (PV)
- Non-Hodgkin lymphoma (NHL): Rituximab Injection reduces the immune response, which reduces inflammation and pain in patients with non-Hodgkin's lymphoma, a type of cancer of the white blood cells. Targeting the B-cell CD20 antigen helps the immune system eliminate malignant B-cells and decrease their number. It significantly increases treatment efficacy when combined with chemotherapy, increasing response rates and extending the duration of progression-free survival. As a maintenance therapy, it slows the progression of the disease after initial treatment success and helps prevent relapses. It is effective for various NHL types, including diffuse large B-cell lymphomas and follicular, low-grade, and relapsed situations.
- Rheumatoid arthritis (RA): In treating inflammation, pain, and swelling in rheumatoid arthritis, Rituximab Injection diminishes the patient's immune system response. It targets the CD20 antigen on B-cells, effectively reducing inflammation and arresting disease progression. When used with other therapies, especially in patients with insufficient responses to tumour necrosis factor (TNF) antagonist therapies, it significantly boosts symptom relief and enhances joint function. Its mechanism involves modulation of the immune response and suppression of B-cell activity, leading to reduced joint damage and an overall improvement in the patient's quality of life.
- Blood cancer (Chronic lymphocytic leukaemia): By killing cancerous B-cells and preventing their growth, rituximab injection slows the progression of the disease. Rituximab targets the CD20 antigen on B-cells. Combined with other therapies, this chronic lymphocytic leukaemia (CLL) treatment significantly improves response rates and lengthens remission times. It weakens the body's defences against infection, essential for controlling blood cancer. Because it inhibits the growth of cancerous B cells, Rituximab can slow the progression of CLL, a cancer of the blood-forming tissues, and increase overall survival rates.
- Granulomatosis with polyangiitis (GPA): Rituximab effectively manages symptoms and disease progression in granulomatosis with polyangiitis (GPA) by reducing inflammation, pain, and swelling while preventing further damage. Targeting B-cells and modulating the immune response controls inflammation and reduces the severity of GPA symptoms affecting blood vessels in the ears, nose, throat, lungs, and kidneys. When combined with glucocorticoids, this treatment suppresses disease activity and prevents relapses, ultimately improving the overall management and quality of life for individuals affected by GPA.
- Microscopic polyangiitis (MPA): Rituximab reduces inflammation and the immune response in microscopic polyangiitis (MPA), effectively controlling symptoms and stopping the disease's progression. It reduces inflammatory mediators associated with vessels in MPA, targets B-cells, and modifies the immune response. It significantly improves the overall management of MPA by suppressing disease activity, reducing the severity of organ-related symptoms, and preventing relapses when combined with glucocorticoids.
- Pemphigus Vulgaris (PV): Skin and mucous membrane blistering is a symptom of the autoimmune disease Pemphigus vulgaris (PV). By explicitly targeting B-cells and modifying the immune response, Rituximab efficiently lowers blister formation, inflammation, and the intensity of PV symptoms. Its application promotes better skin healing, less blistering, and better disease control in moderate-to-severe photovoltaic disease (PV) cases, especially when alternative treatments are inadequate. Combined with other standard therapies, this therapy significantly improves the quality of life for those suffering from PV.
Rituximab is indicated for the following health conditions:
- Treatment for relapsed or refractory, low-grade or follicular, CD20-positive, B-cell NHL as a single agent.
- In initial untreated follicular, CD20-positive, B-cell NHL combined with first-line chemotherapy. It is also used in patients responding to rituximab products combined with chemotherapy for single-agent maintenance therapy.
- Treats non-progressing low-grade, CD20-positive, B-cell NHL as a single agent post-first-line cyclophosphamide, vincristine, and prednisone (CVP) chemotherapy.
- In patients with previously untreated diffuse large B-cell, CD20-positive NHL combined with CHOP or other anthracycline-based chemotherapy regimens.
- For untreated and previously treated CD20-positive CLL, in combination with fludarabine and cyclophosphamide (FC).
- In combination with methotrexate for moderately-to-severely-active RA in adults who have had an inadequate response to ≥1 tumour necrosis factor (TNF) antagonist therapies.
- In adults with granulomatosis with polyangiitis (GPA; Wegener granulomatosis) in combination with glucocorticoids.
- Used for adults with microscopic polyangiitis (MPA) in combination with glucocorticoids.
- For adults with moderate-to-severe pemphigus vulgaris (PV).
- For children aged ≥2 years with granulomatosis with polyangiitis (GPA) (Wegener granulomatosis) and microscopic polyangiitis (MPA) in combination with glucocorticoids.
- Combine with chemotherapy for pediatric patients aged ≥6 months with previously untreated, advanced-stage, CD20-positive diffuse large B-cell lymphoma (DLBCL), Burkitt lymphoma (BL), Burkitt-like lymphoma (BLL), or mature B-cell acute leukaemia (B-AL). The treatment and systemic Lymphome Malin B (LMB) chemotherapy are administered.
Limitations of Use: Rituximab is not recommended in patients with severe, active infections.
Parenterally: Administer Rituximab exclusively via IV infusion; avoid IV push or bolus. Typically, dilute it in a sterile saline or dextrose solution and infuse slowly over several hours, usually between 2 and 6 hours, based on the prescribed dosage and patient tolerance. Before infusion, visually inspect the solution in vials for clarity and absence of particles; avoid using if particles are present. Initiate the infusion at a slower rate for monitoring adverse reactions. Premedications like antihistamines or corticosteroids may be given to patients before infusion to minimize infusion-related reactions. For a rapid 90-minute infusion, administer the glucocorticoid part of the chemotherapy regimen before the infusion. For conditions like RA, GPA, MPA, and PV, administer Methylprednisolone 100 mg IV (or equivalent) 30 minutes before each infusion.
The dosage and duration of treatment should be as per the treating physician's clinical judgment.
100 mg/10 mL and 500 mg/50 mL solution in a single-use vial.
Rituximab is available as an injectable solutions.
Dose Adjustment in Adult Patients:
- NHL, or non-Hodgkin lymphoma
low-grade or follicular, CD20-positive B-cell NHL that has relapsed or is refractory.
IV 375 mg/m2 once a week for four to eight doses
Retreatment: IV 375 mg/m2 once every week for four doses
when coupled with ibritumomab
Rituximab 250 mg/m2 IV on Day 1; on Days 7, 8, or 9: IV rituximab 250 mg/m2; give ibritumomab 4 hours after the infusion.
For complete regimen prescribing information, see ibritumomab tiuxetan.
Previously untreated CD20-positive follicular B-cell NHL
375 mg/m2 IV for up to eight doses on Day 1 of every chemotherapy cycle
In patients who show a complete or partial response to combination chemotherapy, maintenance therapy is administered eight weeks later. Start with a single agent every eight weeks for twelve doses.
when coupled with ibritumomab
Day 1: Intravenous Rituximab 250 mg/m2
Day 7, 8, or 9: IV rituximab 250 mg/m2; ibritumomab was administered 4 hours after the infusion.
For complete regimen prescribing information, see ibritumomab tiuxetan.
Low-grade, CD20-positive B-cell NHL that is not progressing (including stable disease)
After 6–8 cycles of CVP chemotherapy, administer 375 mg/m2 IV once weekly for up to 16 doses (four doses spaced six months apart).
Diffuse large B-cell, CD20-positive NHL that was previously untreated
375 mg/m2 IV on the first day of every chemotherapy cycle for a maximum of eight infusions.
- Chronic Lymphocytic Leukemia(CLL)
In patients with untreated, relapsed, or refractory cases, in conjunction with chemotherapy: 375 mg/m2 by infusion on the day before chemotherapy in cycle 1, then 500 mg/m2 on day 1 of each subsequent cycle, up to 6 cycles. Begin the first infusion at 50 mg/hour and increase every 30 minutes by 50 mg/hour; subsequent doses may be infused at 100 mg/hour and increased by 100 mg/hour increments every 30 minutes, with a maximum rate of 400 mg/hour. Alternatively, on day 1 of each subsequent cycle (6 cycles), start at least one total dose of rituximab IV infusion and then administer an SC of 1,600 mg over approximately 7 minutes. Before beginning each infusion, take an antihistamine and paracetamol; glucocorticoids might also be considered if they are not part of the chemotherapy treatment plan. Therapy for prevention may also be administered.
- Wegener Granulomatosis
Induction therapy involves 375 mg/m2 IV of Rituximab weekly for 4 weeks. Follow-up treatment depends on the induction regimen's response: if controlled by Rituximab, initiate follow-up within 24 weeks after the last induction dose; if controlled by other immunosuppressants, start follow-up within 4 weeks of disease control. The subsequent treatment involves 500 mg IV on Days 1 and 15, then every 6 months after clinical evaluation. Methylprednisolone and prednisone are recommended for severe symptoms, starting 14 days before rituximab initiation and continuing throughout therapy. Methylprednisolone premedication precedes each rituximab infusion.
- Microscopic Polyangiitis
In patients with severe, active cases, in addition to glucocorticoids, Induction therapy: four weekly doses at 375 mg/m2. Maintenance therapy consists of 500 mg given twice a week for two weeks and then 500 mg once every six months after that. Doses to be administered by infusion. First infusions can start at 50 mg/hour and go up by 50 mg/hour increments every 30 minutes; second and subsequent doses can begin at 100 mg/hour and go up by 100 mg/hour increments every 30 minutes, with a maximum rate of 400 mg/hour. Before every infusion, take an antihistamine and some paracetamol. As directed by clinical guidelines, provide prophylaxis for Pneumocystis jirovecii pneumonia both during and after treatment.
- Pemphigus Vulgaris
For cases ranging from moderate to severe, take 1,000 mg twice over two weeks. Maintenance: 500 mg at months 12 and 18, then, if needed, every six months after that, depending on the results of the clinical evaluation. Doses to be administered by infusion. First infusions can start at 50 mg/hour and go up by 50 mg/hour increments every 30 minutes; second and subsequent doses can begin at 100 mg/hour and go up by 100 mg/hour increments every 30 minutes, with a maximum rate of 400 mg/hour. If relapse occurs, an infusion of 1,000 mg may be administered. A second infusion can be given up to sixteen weeks following the first one. Administer glucocorticoids (e.g., methylprednisolone) half an hour before each infusion; premedicate with paracetamol and antihistamine beforehand. Following clinical guidelines, give prophylaxis against Pneumocystis jirovecii pneumonia both during and after treatment.
While on Rituximab, managing side effects is possible through dietary adjustments. Individuals with chronic illnesses, including cancer, should prioritize foods rich in protein, healthy fats, whole grains, vitamins, and minerals. Plant-based proteins, like nuts, seeds, beans, and legumes, are highly recommended during cancer treatments due to their abundant nutrient content. Incorporate leafy greens, citrus fruits, fatty fish, berries, yoghurt, apples, peaches, cauliflower, cabbage, broccoli, beans, and herbs into your meals. It's advised to avoid smoking, alcohol, fast foods, fried items, processed meats, refined carbohydrates, and added sugars to optimize your health while on this medication.
The dietary restriction should be individualized as per patient requirements.
- Individuals with known hypersensitivity to Rituximab or any of its components should avoid its use.
- Severe active infections.
- Live virus vaccines.
- Tumour lysis syndrome must be managed with aggressive intravenous hydration, anti-hyperuricemic medications, and renal function monitoring.
- Monitor neurologic function for potential progressive multifocal leukoencephalopathy (PML). Discontinue Rituximab if suspected.
- High-risk patients and HBV carriers should undergo screening and continuous monitoring for hepatitis B reactivation, which can be fatal. Cease Rituximab if reactivation occurs.
- In cases of infections, hold Rituximab and initiate appropriate anti-infective therapy.
- Cardiac arrhythmias and angina can pose life-threatening risks. Close monitoring is essential for patients with these conditions.
- Evaluate complaints of abdominal pain promptly for possible bowel obstruction or perforation.
- Avoid administering live virus vaccines before or during Rituximab treatment.
- Regularly monitor complete blood count (CBC) for severe cytopenias to ensure timely intervention.
Alcohol Warning
It is unsafe to consume Rituximab with alcohol.
Breast Feeding Warning
It is not recommended for use during breastfeeding.
Pregnancy Warning
It is not recommended for use during pregnancy.
Food Warning
Consume proteins and whole foods; avoid smoking, alcohol, and processed foods.
The adverse reactions related to Rituximab can be categorized as:
Common Adverse Effects: Pain at the injection site, headaches, weakness, fever, chills, and a reduced white blood cell count (neutrophils).
Less Common Adverse Effects: Lymphopenia, abdominal and back pain, pale skin, painful urination, night sweats, and flushing.
Rare Adverse Effects: Vomiting, diarrhoea, stomach discomfort, mouth sores, skin peeling, coughing, and bruising or bleeding gums.
Reports on post-marketing
Polyserositis
Pulmonary hypertension
Reversible posterior leukoencephalopathy syndrome (RPLS)
Osteonecrosis of the jaw
Eye disorders (permanent loss of vision, endophthalmitis, etc.)
Gastrointestinal ulcer
Pancytopenia
Hepatitis B reactivation with fulminant hepatitis
Cardiac arrhythmias
Bowel obstruction and perforation
Do not administer live virus vaccines before or during Rituximab treatment.
Monitor CBC at regular intervals for severe cytopenias.
The clinically relevant drug interactions of Rituximab are briefly summarized here.
- Drug-Drug Interactions: Rituximab may have interactions with other medications, vaccines, and disease-modifying antirheumatic drugs (DMARDs) other than methotrexate and antineoplastics like cisplatin; observe closely for signs of infection when used concomitantly.
- There were no drug-food interactions found.
- Drug-Disease Interactions: Before taking Rituximab, inform the physician of any gastrointestinal, pulmonary, or kidney diseases.
The common side effects of Rituximab include pain at the injection site, headache, weakness, infection, chills, reduced white blood cell count (neutrophils), fever, lymphopenia, abdominal and back pain, pale skin, painful urination, night sweats, flushing, vomiting, diarrhoea, stomach pain, mouth sores, skin peeling, coughing, and bruising or bleeding gums.
- Pregnancy
Pregnancy Category C (FDA): Use caution if the benefits outweigh the risks.
Before starting treatment, determine whether any females capable of bearing children are pregnant.
It may result in harmful developmental outcomes, such as B-cell lymphocytopenia in infants exposed to Rituximab during pregnancy, according to human data.
Monitor for symptoms of infection in newborns and infants and take appropriate action.
Animal data
When given intraperitoneally (IV) to pregnant cynomolgus monkeys during organogenesis, the doses resulted in 80% exposure (based on AUC) of what would be achieved after a 2-gram dose in humans for the newborn offspring.
Inform expectant mothers of potential risks to the fetus
Contraception
Women who are capable of bearing children: Use effective contraception both during treatment and for an entire year after.
- Nursing Mothers
Information on the presence of drugs in human milk, their effects on breastfed infants, or their effects on the production of milk is unavailable.
Indicated to be present in human milk and found in the milk of nursing cynomolgus monkeys.
Since Rituximab is excreted in human breast milk at low concentrations, it is advised that women refrain from breastfeeding their children while undergoing treatment and for six months following the last dose because there is a chance that their child may experience severe adverse reactions.
- Pediatric Use
Dose adjustment
Granulomatosis with Polyangiitis
≥2 years Combined with glucocorticoids: Induction therapy: an intravenous infusion of 375 mg/m2 weekly for four weeks. Maintenance therapy entails an injection of 250 mg/m2 for two doses spaced two weeks apart, followed by 250 mg/m2 every six months, contingent upon clinical evaluation. Before every infusion, take an antihistamine and some paracetamol. When necessary, administer prophylaxis against Pneumocystis jirovecii pneumonia both during and after treatment.
Microscopic polyangiitis
≥2 years Combined with glucocorticoids: Induction therapy: an intravenous infusion of 375 mg/m2 weekly for four weeks. Maintenance therapy entails an injection of 250 mg/m2 for two doses spaced two weeks apart, followed by 250 mg/m2 every six months, contingent upon clinical evaluation. Before every infusion, take an antihistamine and some paracetamol. When necessary, administer prophylaxis against Pneumocystis jirovecii pneumonia both during and after treatment.
Non-Hodgkin Lymphoma
Each rituximab infusion is administered with systemic Lymphome Malin B (LMB) chemotherapy. Patients receive premedication with acetaminophen and diphenhydramine (or equivalent) 30-60 minutes before each infusion. During induction courses 1 and 2, two rituximab infusions are given in each course, part of the COPDAM regimen (Cyclophosphamide, vincristine, prednisolone, doxorubicin, methotrexate). On Day -2, a dose of 375 mg/m2 IV is administered for the first and third infusions, while on Day 1, the second and fourth infusions receive the exact dosage 48 hours after the first rituximab infusion. For consolidation courses 1 and 2, a single rituximab infusion is given during each CYM/CYVE regimen (Cytarabine, methotrexate / Cytarabine, etoposide). On Day 1, the fifth and sixth infusions are given at 375 mg/m2 IV doses for each course.
- Geriatrics (> 65 years old) Use
Research has been done on the effectiveness and safety of Rituximab in elderly patients. Compared to younger adults, elderly patients (65 years of age and above) usually show comparable treatment outcomes. Careful monitoring and dosage adjustments based on individual tolerability are advised, even though they may have a slightly higher risk of specific side effects. Overall, geriatric populations treated with Rituximab have demonstrated safety profiles and efficacy comparable to those reported in younger age groups.
Dose Adjustment in Kidney Impairment Patients:
Reduce rituximab dose for patients with severe renal impairment or end-stage renal disease (ESRD) undergoing hemodialysis.
For severe renal impairment (CrCl < 30 mL/min) or ESRD on hemodialysis, reduce the dose proportionally.
No dose adjustment is needed for mild to moderate renal impairment (CrCl ≥ 30 mL/min).
Dose Adjustment in Hepatic Impairment Patients:
For hepatic impairment: No specific dose adjustments are recommended for patients with mild to moderate liver impairment. Limited data is available for severe impairment; exercise caution and consider reducing the rituximab dose in extreme cases.
The physician should be vigilant about the knowledge pertaining to identifying and treating overdosage of Rituximab.
Signs and Symptoms
Overconsumption of Rituximab could lead to Flu-like symptoms and severe respiratory failure.
Management
The management of Rituximab overdose involves supportive measures and symptomatic treatment. There isn't a specific antidote. Consider measures like gastric lavage or activated charcoal if the overdose was recent. Consider symptomatic and supportive care, monitoring vital signs, and providing appropriate treatment for adverse reactions or complications. Due to its slow elimination, extended observation for potential delayed effects is advisable.
Pharmacodynamics:
In Non-Hodgkin's Lymphoma, Rituximab effectively reduced CD19-positive B-cells in 83% of patients for 6-9 months, with recovery starting at 6 months and normalization by 12 months post-treatment. 14% of patients showed IgM or IgG levels below normal.
Rheumatoid arthritis patients exhibited profound peripheral B-cell depletion for over 6 months post-rituximab, and in 4% of cases, it lasted over 3 years. Immunoglobulin levels were notably lower, but their clinical implications remain uncertain. Rituximab treatment reduced inflammation markers in RA.
CD19 B-cell counts decreased after two rituximab infusions in granulomatosis with polyangiitis and microscopic polyangiitis. By Month 18, 87% of patients had counts >10 cells/μL, indicating B-cell recovery after initial depletion.
Pharmacokinetics:
- Absorption: Rituximab is administered intravenously, allowing direct entry into the bloodstream without oral absorption considerations typical of other medications.
- Distribution: Post-administration, Rituximab disseminates across various body compartments, crosses the placenta, and enters breast milk. Its volume of distribution stands at 3.1 L (rheumatoid arthritis [RA]), 3.49 L [range: 2.48-5.22 L] (pemphigus vulgaris), and 3.12 L [range: 2.42-3.91 L] (granulomatosis with polyangiitis/microscopic polyangiitis) for intravenous administration and 8.52 L (chronic lymphocytic leukaemia [CLL]) and 8.09 L (follicular lymphoma) for subcutaneous administration.
- Metabolism: Rituximab doesn’t undergo typical metabolism akin to small-molecule drugs. Instead, it binds to CD20 antigen-presenting B-cells, causing their depletion without traditional metabolic transformation.
- Elimination: Elimination occurs via clearance by the reticuloendothelial system and renal excretion. The drug’s elimination half-life spans days to weeks, with RA: 18 days (range: 5-78 days), non-Hodgkin's lymphoma: 22 days (range: 6-52 days), granulomatosis with polyangiitis/microscopic polyangiitis: 25 days (range: 11-52 days), CLL: 32 days (range: 14-62 days), and pemphigus vulgaris: 1st cycle: 21.1 days (range: 9.3-36.2 days), 2nd cycle: 26.2 days (range: 16.4-42.8 days).
- Merrill JT, Neuwelt CM, Wallace DJ, Shanahan JC, Latinis KM, Oates JC, Utset TO, Gordon C, Isenberg DA, Hsieh HJ, Zhang D, Brunetta PG. Efficacy and safety of rituximab in moderately-to-severely active systemic lupus erythematosus: the randomized, double-blind, phase II/III systemic lupus erythematosus evaluation of rituximab trial. Arthritis Rheum. 2010 Jan;62(1):222-33. doi: 10.1002/art.27233. PMID: 20039413; PMCID: PMC4548300.
- Dotan E, Aggarwal C, Smith MR. Impact of Rituximab (Rituxan) on the Treatment of B-Cell Non-Hodgkin's Lymphoma. P T. 2010 Mar;35(3):148-57. PMID: 20442809; PMCID: PMC2844047.
- Chisari CG, Sgarlata E, Arena S, Toscano S, Luca M, Patti F. Rituximab for the treatment of multiple sclerosis: a review. J Neurol. 2022 Jan;269(1):159-183. doi: 10.1007/s00415-020-10362-z. Epub 2021 Jan 8. PMID: 33416999; PMCID: PMC7790722.
- Grillo-López AJ, White CA, Varns C, Shen D, Wei A, McClure A, Dallaire BK. Overview of the clinical development of rituximab: first monoclonal antibody approved for the treatment of lymphoma. Semin Oncol. 1999 Oct;26(5 Suppl 14):66-73. PMID: 10561020.
- https://www.ncbi.nlm.nih.gov/books/NBK564374/
- https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfmsetid=da1c4de7-0e5b-4f72-97ec-7a8d368f085f.
- https://www.accessdata.fda.gov/drugsatfda_docs/label/2010/103705s5311lbl.pdf
- https://www.gene.com/download/pdf/rituxan_prescribing.pdf
Dr. Chumbeni E Lotha has completed her Bachelor of Pharmacy from RIPANS, Mizoram and Doctor of Pharmacy from SGRRU,Dehradun. She can be reached at editorial@medicaldialogues.in
Dr JUHI SINGLA has completed her MBBS from Era’s Lucknow Medical college and done MD pharmacology from SGT UNIVERSITY Gurgaon. She can be contacted at editorial@medicaldialogues.in. Contact no. 011-43720751
Published on: 10 Jan 2024 4:55 AM GMT