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Comparing a new biosimilar to Enbrel for treating rheumatoid arthritis

A Prospective, Randomized, Double-blind, Parallel-group Study to Compare the Efficacy, Safety, Pharmacokinetics and Immunogenicity of MB04 and EU-sourced Enbrel® in Patients with Moderate to Severe Rheumatoid Arthritis

PHASE3 · mAbxience Research S.L. · NCT06596772

This study is testing a new treatment for rheumatoid arthritis to see if it works as well as Enbrel for people who haven't had enough relief from their current medication.

Quick facts

PhasePHASE3
Study typeInterventional
Enrollment458 (estimated)
Ages18 Years to 75 Years
SexAll
SponsormAbxience Research S.L. (industry)
Drugs / interventionsprednisone, methotrexate
Locations60 sites (Haskovo and 59 other locations)
Trial IDNCT06596772 on ClinicalTrials.gov

What this trial studies

This study aims to compare the efficacy, pharmacokinetics, safety, and immunogenicity of MB04, a proposed biosimilar to etanercept, against the EU-sourced Enbrel in patients with active rheumatoid arthritis who have not responded adequately to methotrexate therapy. Approximately 458 patients aged 18 to 75 will be randomized to receive either MB04 or Enbrel subcutaneously for 36 weeks, with assessments conducted at various intervals to monitor treatment effects. The study includes a transition period where patients originally assigned to Enbrel may switch to MB04 after the initial treatment phase. Safety follow-up will occur for four weeks post-treatment.

Who should consider this trial

Good fit: Ideal candidates are adults aged 18 to 75 with a documented history of moderate to severe rheumatoid arthritis despite stable methotrexate therapy.

Not a fit: Patients with rheumatoid arthritis who have not been on methotrexate or those with contraindications to the study medications may not benefit from this study.

Why it matters

Potential benefit: If successful, this study could provide an effective alternative treatment option for patients with rheumatoid arthritis who are not adequately managed with current therapies.

How similar studies have performed: Other studies have shown success with biosimilars in treating rheumatoid arthritis, indicating that this approach is promising and not entirely novel.

Eligibility criteria

Show full inclusion / exclusion criteria 
Inclusion

* Documented history of RA diagnosis consistent with the 2010 ACR/EULAR classification criteria ≥6 months prior to randomization (but not exceeding 15 years prior to screening).
* Moderately to severe RA despite appropriate MTX at baseline therapy defined as having more than or equal to six swollen joints and more than or equal to six tender joints and either erythrocyte sedimentation rate (ESR, Westergren) ≥ 28 mm/h or serum C-reactive protein \> 5.0 mg/dL and positive rheumatoid factor and/or CCP at screening
* Stable dose MTX between 10 to 25 mg weekly during ≥12 weeks, since ≥8 weeks prior to randomization
* Stable dose of NSAID and /or other analgesics for at least 4 weeks prior to randomization, when used
* Stable dose ≤10 mg prednisone daily or equivalent for ≥4 weeks prior to randomization, when used
* Patients who are otherwise medically stable according to investigator\'s discretion
* Agree to use highly effective contraceptive methods up to 6 months after las dose Exclusion
* Previously treated with any biologic or targeted synthetic DMARD
* Previously treated with any monoclonal antibody for other condition than RA
* Hypersensitivity to any component of study drug and/or prefilled syringe components
* Arthritis with onset prior to age 16 years or current diagnosis of inflammatory joint disease other than RA
* Systemic manifestations of RA other that rheumatoid nodules or secondary Sjogren\'s syndrome
* Active infection or potentially relapsing infections that could have a severe outcome. Latent tuberculosis infection detected during screening should start an approved treatment regimen according to standard of care and rescreened
* Solid or hematologic malignancy within the past 5 years
* Pregnant and breastfeeding women
* Any medical condition in the opinion of the investigator that would be a risk for safety, cooperation in the study or interferes with the interpretation of the study results

Where this trial is running

Haskovo and 59 other locations

+10 more sites — see ClinicalTrials.gov for the full list.

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.

View on ClinicalTrials.gov →

Conditions: Rheumatoid Arthritis

Last reviewed 2026-05-15 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.