Infliximab Dosing and Treatment Protocol for Autoimmune Diseases
The standard infliximab dosing regimen for autoimmune diseases is 5 mg/kg administered intravenously at weeks 0,2, and 6 for induction, followed by maintenance infusions every 8 weeks. 1
Dosing by Specific Condition
Psoriasis and Psoriatic Arthritis
- Infliximab is administered at 5 mg/kg intravenously at weeks 0,2, and 6 (induction), then every 8 weeks for maintenance 1
- Short-term response is rapid, with 50% PASI improvement noted by week 2 and 80% of patients achieving PASI-75 by week 10 1
- Long-term response shows 61% of patients maintaining PASI-75 at week 50 1
- For incomplete responders, dose may be increased up to 10 mg/kg or intervals shortened based on clinical need 2
Crohn's Disease and Ulcerative Colitis
- Standard dosing is 5 mg/kg IV at weeks 0,2, and 6 for induction, followed by maintenance every 8 weeks 1
- Combination therapy with a thiopurine is strongly recommended for the first 6-12 months of treatment to improve efficacy and reduce immunogenicity 1
- After achieving long-term remission with combination therapy, thiopurines can be withdrawn in most patients 1
Rheumatoid Arthritis
- Infliximab is administered at 3-5 mg/kg IV at weeks 0,2, and 6, then every 8 weeks 3
- Co-administration with methotrexate is recommended to delay the decline in serum concentrations of infliximab 3
Ankylosing Spondylitis
- Standard dosing is 5 mg/kg IV at weeks 0,2, and 6, then every 8 weeks 4
- For patients with stable disease, treatment should continue long-term as discontinuation results in relapses in 60-74% of patients 4
Monitoring and Safety Considerations
Baseline Assessments
- Tuberculosis testing (PPD) is required before starting treatment 1
- Complete blood count (CBC) and liver function tests (LFT) should be performed 1
- Hepatitis profile is recommended 1
- Patients with New York Heart Association functional class III or IV congestive heart failure should not receive infliximab at doses ≥5 mg/kg 1
Ongoing Monitoring
- Periodic history and physical examination while on treatment 1
- Consider yearly tuberculosis testing 1
- Periodic CBC and LFT monitoring 1
Common Adverse Effects
- Infusion reactions occur in up to 20% of patients, particularly those who have developed antibodies to infliximab 1
- Serious infections, including tuberculosis, may occur 1
- Biological autoimmunity with development of antinuclear antibodies is common (72% of patients by week 22) 5
- Rare but serious side effects include hepatosplenic T-cell lymphoma, lupus-like syndrome, demyelinating disease, and exacerbation of heart failure 1
Optimizing Treatment Response
Combination Therapy
- Concomitant methotrexate reduces antibody formation against infliximab and improves long-term efficacy 1
- In Crohn's disease, combination with thiopurines for at least 6-12 months is strongly recommended 1
- Continuous therapy is preferred over intermittent treatment to reduce immunogenicity and maintain clinical response 1
Therapeutic Drug Monitoring
- Trough concentrations above 1 μg/mL could be used as a therapeutic target for patients with rheumatoid arthritis and Crohn's disease 3
- Dose adjustments may be needed based on clinical response and drug levels 1
Special Considerations
Pregnancy
- Infliximab is pregnancy category B 1
Treatment Duration
- For psoriasis and psoriatic arthritis, continuous therapy shows better maintenance of response than intermittent therapy 1
- For ankylosing spondylitis, long-term treatment is recommended as discontinuation leads to high relapse rates 4
- For Crohn's disease with long-term remission on combination therapy, consider de-escalation to infliximab monotherapy 1