• Skip to primary navigation
  • Skip to main content
  • Skip to primary sidebar
  • Skip to footer

Johns Hopkins Arthritis Center

Show Search
Hide Search
  • Disease Information
    • Rheumatoid Arthritis
    • Psoriatic Arthritis
    • Ankylosing Spondylitis
    • Osteoarthritis
    • Gout
    • Osteoporosis
  • Patient Corner
    • Drug Information Sheets
    • Managing Your Arthritis
    • RheumTV – Patient Education Video Library
  • Our Research
    • Patient-Centered Outcomes Research
    • Current Research Studies
    • The Camille Julia Morgan Arthritis Research and Education Fund
  • About Us
    • Appointment Information
    • Contact Us
    • Our Faculty
    • Our Staff
    • Rheumatology Specialty Centers
    • News & Updates
  • Donate
Home / Arthritis News / Does the Serum Concentration of Infliximab (Remicade) Predict Clinical Response?

Does the Serum Concentration of Infliximab (Remicade) Predict Clinical Response?

April 13, 2005 By Arthritis Center

St. Clair et al. (Arthr and Rheum. 6:1451-1459; 2002) evaluated the relationship of the serum concentration of infliximab to the clinical efficacy of RA in subjects who had participated in the ATTRACT clinical trial, a double-blinded, placebo-controlled trial of infliximab and methotrexate compared to methotrexate alone.

Methods:

428 patients with active RA taking stable doses of methotrexate (>12.5 mg), NSAIDS, and prednisone (< 10mg) were randomized to placebo, 3mg/kg or 10 mg/kg of infliximab on a every 4 or 8 week dosing regimen following an induction phase at weeks 0, 2, and 6. Assessments of the ACR clinical response were completed prior to dosing and included the ACR-N which is used to assess continuous measurement of clinical response. Serum concentrations were also obtained prior to dosing and one hour post-dosing. Infliximab levels were measured by ELISA (lowest detectable level = 0.1 μg/ml). Modeling serum profiles for each of the dosing regimens were used to determine the benefit of a dose increase versus a change in dosing interval frequency to achieve adequate clinical response.

Results:

Trough serum levels of infliximab corresponded with the magnitude of ACR response. There was no significant difference in observed ACR20 response rates across the infliximab treatment groups, however, ACR50 and ACR70 response rates increased with increased serum trough levels. Thus, an ACR50 response rate of 21.5% observed in the 3mg/kg every 8 weeks which was significantly lower than that observed in the 10 mg/kg groups at every 4 weeks (34.1%) and 10mg/kg every 8 weeks (40%). The greatest percentage (26%) of ACR20 non-responders at week 54 displayed serum trough levels of <0.1mg/ml observed in the group receiving 3mg/kg of infliximab every 8 weeks which was significant in comparison to the other 3 treatment groups (P<0.001). Importantly, greater reductions in baseline serum CRP levels correlated with the higher serum trough levels of infliximab (P<0.001) and likewise with less radiographic progression of joint damage (p<0.004). Finally, pharmacokinetic modeling demonstrated that for patients with undetectable trough levels, decreasing the dosing interval from 8 weeks to 6 weeks raised serum trough levels to a greater extent than increasing the dose by 1 vial of drug (100mg).

Conclusion:

Significantly greater improvement in ACR responses, reduction of CRP levels, and less radiographic progression of joint damage observed with higher trough serum infliximab concentrations, corresponding with increased doses of infliximab, suggests that clinical efficacy is dose dependent. Therefore, patients who demonstrate a lack of treatment response may benefit from dose escalation, and/or decreasing the interval between doses, to increase trough serum concentrations of infliximab.

Editorial Comments:

Many patients have noted a breakthrough in their joint pain and swelling during the last 2 weeks of their 8-week intervals between infliximab dosing. This study provides some scientific rationale for this “breakthrough” and some guidance for altering the dosing regimen in individual patients. However, it is important to note that some patients in this study had dramatic clinical (ACR 70 and ACR 90) responses even with undetectable serum levels of infliximab. Correlation of serum levels and clinical response is still imprecise, and this study does not help us predict who will be a “good responder” vs. a “non-responder”.

Receive the Latest News from Johns Hopkins Rheumatology

Receive the Latest News from Johns Hopkins Rheumatology

Join our mailing list to receive the latest news and updates from Johns Hopkins Rheumatology.

Interested In

You have Successfully Subscribed!

Arthritis Center

Founded in 1998, the Arthritis Center at Johns Hopkins is dedicated to providing quality education to patients and healthcare providers alike.

Use of this Site

All information contained within the Johns Hopkins Arthritis Center website is intended for educational purposes only. Physicians and other health care professionals are encouraged to consult other sources and confirm the information contained within this site. Consumers should never disregard medical advice or delay in seeking it because of something they may have read on this website.

Primary Sidebar

Recent News

Exercise Tips for Arthritis Patients

How Does Exercise Affect my Joints? How Frequently Should I Be Exercising? Should I Lose Weight for Exercise to be

Risks and Benefits of Biologic Medications

Victoria Ruffing, RN, BC, Director of Patient Education at the Johns Hopkins Arthritis Center, shares the risks and benefits of biologic for

How to Manage Rheumatoid Arthritis Flares

Through research, doctors have a clearer understanding of how flares can impact a patient on a personal and emotional level. Dr. Uzma Haque

Complementary & Alternative Medicines for Psoriatic Arthritis

There are many complementary & alternative medicines and practices that have been found to be beneficial in curbing arthritis pain,

I can’t be a runner because I have Rheumatoid Arthritis (RA), right?

Dr. Manno discusses running and Rheumatoid Arthritis. Is it an option for the RA patient?

News Categories

  • Ankylosing Spondylitis News
  • Fibromyalgia News
  • Gout News
  • Lupus News
  • Osteoarthritis News
  • Osteoporosis News
  • Psoriatic Arthritis News
  • Rheumatoid Arthritis News
RheumTV Logo

Rheum.TV is an informational platform created to educate patients living with a rheumatic disease. With over 100 disease education videos produced by the team at Johns Hopkins Rheumatology.

Visit Rheum.TV

Footer

Johns Hopkins Rheumatology

  • Johns Hopkins Rheumatology
  • Johns Hopkins Lupus Center
  • Johns Hopkins Lyme Disease Research Center
  • Johns Hopkins Myositis Center
  • Johns Hopkins Scleroderma Center
  • Johns Hopkins Sjögren’s Syndrome Center
  • Johns Hopkins Vasculitis Center

Connect With Us

  • Facebook
  • Twitter
  • YouTube

Johns Hopkins Medicine

© 2025 Johns Hopkins Arthritis Center
Patient Privacy