What are the considerations for using infliximab in a patient with inflammatory conditions, such as rheumatoid arthritis or Crohn's disease, who is already on prednisone?

Using Infliximab in Patients Already on Prednisone

Infliximab can and should be initiated in patients currently taking prednisone for moderate to severe inflammatory conditions, with the goal of achieving corticosteroid-free remission and ultimately discontinuing prednisone. 1, 2

Rationale for Combination Therapy

• Prednisone is not recommended for maintenance therapy in Crohn's disease or other inflammatory conditions, making the addition of infliximab essential for achieving durable, steroid-free remission 1
• The Canadian Association of Gastroenterology strongly recommends anti-TNF therapy (including infliximab) for patients with moderate to severe Crohn's disease, which includes those currently on corticosteroids who have failed to achieve adequate control 1, 3
• Patients should be evaluated for symptomatic response to prednisone within 2-4 weeks; if response is inadequate or if steroid-dependency develops, infliximab should be initiated 1

Optimal Timing and Dosing Strategy

• Initiate infliximab while the patient is still on prednisone rather than waiting for prednisone to be tapered, as this approach facilitates achieving corticosteroid-free remission 2, 3
• Standard induction dosing is 5 mg/kg IV at weeks 0,2, and 6, followed by maintenance dosing every 8 weeks 3, 4
• Patients should be reviewed 2-4 weeks after completing the loading doses to assess response and optimize maintenance dosing 1, 2

Concomitant Immunosuppression Considerations

• Combination therapy with thiopurines (azathioprine or 6-mercaptopurine) when starting infliximab is strongly recommended for at least 6-12 months, as this reduces immunogenicity and improves outcomes 2, 3
• Concomitant methotrexate is required for rheumatoid arthritis patients and delays the decline in infliximab serum concentrations 5, 6
• The combination of prednisone with infliximab and an immunomodulator (thiopurine or methotrexate) is acceptable during the induction phase, with the goal of tapering prednisone once infliximab achieves therapeutic effect 7

Prednisone Tapering Strategy

• Once clinical response to infliximab is documented (typically by weeks 8-12), begin tapering prednisone gradually 1, 2
• Avoid abrupt discontinuation of prednisone; taper slowly to prevent adrenal insufficiency and disease flare 1
• Monitor inflammatory markers (CRP) and fecal calprotectin during the taper to ensure disease control is maintained 1, 2

Critical Safety Considerations

• Complete mandatory pre-treatment screening before initiating infliximab, including tuberculosis screening (PPD or interferon-gamma release assay), hepatitis B and C serology, complete blood count, and liver function tests 5
• The risk of serious infections is approximately twofold higher with infliximab, and this risk may be further increased when combined with corticosteroids and other immunosuppressants 5
• Patients must be screened for active infections and should not receive infliximab until any infection is adequately treated 5, 7
• Avoid live vaccines while on infliximab therapy 5

Monitoring During Combined Therapy

• Assess clinical response at weeks 8-12 after initiating infliximab using disease activity scores, inflammatory markers (CRP), and fecal biomarkers (calprotectin) 1, 2
• Consider therapeutic drug monitoring if there is suboptimal response or loss of response, targeting trough concentrations above 1 mcg/mL 1, 6
• Monitor for signs of infection throughout treatment, including temperature checks and assessment for respiratory symptoms 5
• Periodic complete blood counts and liver function tests are required during ongoing therapy 5

Common Pitfalls to Avoid

• Do not delay infliximab initiation in steroid-dependent patients waiting to taper prednisone first—this prolongs steroid exposure and delays achievement of remission 1, 2
• Do not use prednisone for long-term maintenance after infliximab achieves remission; the goal is complete steroid discontinuation 1
• Do not switch between anti-TNF agents in patients doing well on infliximab, even if they remain on low-dose prednisone 1
• Be aware that concomitant use of azathioprine or 6-mercaptopurine with infliximab increases the risk of hepatosplenic T-cell lymphoma, though this remains rare 5

Expected Outcomes

• Clinical response rates of 20-40% have been achieved with infliximab in Crohn's disease and rheumatoid arthritis in controlled trials 6
• The combination approach allows for steroid-sparing effects and achievement of corticosteroid-free remission in most responders 7
• Infliximab demonstrates rapid onset of action, with many patients showing improvement within 2-4 weeks of the first infusion 8, 9