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Study comparing MB04 (etanercept biosimilar) with Enbrel in patients with moderate to severe rheumatoid arthritis who are taking methotrexate

Verified siteRegistered drugNo placebo
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What is this trial about?

A plain-language summary of the goals, design and what participants do

This study focuses on patients with moderate to severe Rheumatoid Arthritis, a chronic condition that causes joint inflammation, pain, and stiffness. The research compares two medications: MB04 (a proposed new medication) and Enbrel (also known as etanercept). Both medications belong to a group of drugs called tumor necrosis factor alpha inhibitors, which help reduce inflammation in the body.

The purpose of this study is to determine if MB04 works as effectively as Enbrel in treating rheumatoid arthritis. Both medications are given as injections under the skin using pre-filled syringes. During the study, patients will also continue taking methotrexate, which is a standard medication for rheumatoid arthritis treatment.

The treatment period lasts 36 weeks, during which patients receive injections of either MB04 or Enbrel. The maximum daily dose is 50 mg, and the total amount of medication received during the study will not exceed 1800 mg. Throughout the study, doctors will monitor how well the medications work by checking joint symptoms and overall disease activity.

The research process

The trial runs in 5 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Initial treatment phase

    You will receive subcutaneous injections of either MB04 or Enbrel® (50 mg solution). The specific medication will be randomly assigned.

    You will continue taking your current dose of methotrexate (between 10 to 25 mg weekly).

    If you are taking other medications such as NSAIDs, pain relievers, or prednisone (up to 10 mg daily), you will maintain your current doses.

  2. Step 2

    Follow-up visits - weeks 4, 8, and 12

    Your response to treatment will be evaluated during clinic visits.

    The doctor will assess your joint symptoms and overall disease activity using standardized measurements.

    Blood samples may be collected to monitor your response to treatment.

  3. Step 3

    Main assessment - week 24

    A comprehensive evaluation of your treatment response will be performed.

    The doctor will measure improvements in your joint symptoms and daily activities.

    This is the primary timepoint for comparing the effectiveness of the treatments.

  4. Step 4

    Extended follow-up - week 36

    Final evaluation to assess the long-term effectiveness of the treatment.

    The doctor will perform the same assessments as in previous visits.

    This visit marks the end of the active treatment phase.

  5. Step 5

    Safety monitoring

    Throughout the study, your health will be monitored for any side effects.

    You must use effective contraception during the study and for 6 months after the last dose.

    The total duration of your participation will be approximately 36 weeks.

Who can join the trial?

8 criteria

  • Age between 18 to 75 years old (male or female)
  • Diagnosed with Rheumatoid Arthritis for at least 6 months but less than 15 years
  • Have moderate to severe Rheumatoid Arthritis despite taking methotrexate (a medication that reduces inflammation)
  • Taking a stable dose of methotrexate between 10 to 25 mg weekly for at least 12 weeks, with no changes in the last 8 weeks
  • If taking pain medications (NSAIDs - anti-inflammatory drugs like ibuprofen), the dose must be stable for at least 4 weeks
  • If taking prednisone (a steroid medication), the dose must be 10 mg or less per day and stable for at least 4 weeks
  • Be in generally stable health, as determined by the study doctor
  • Willing to use reliable birth control methods during the study and for 6 months after the last dose of study medication

Who cannot join the trial?

14 criteria

  • History of severe allergic reactions or anaphylaxis (life-threatening allergic reaction)
  • Active or chronic infections, including tuberculosis (TB) or hepatitis B
  • History of cancer within the past 5 years (except successfully treated non-melanoma skin cancer)
  • Severe heart conditions, including congestive heart failure (when heart cannot pump blood effectively)
  • Significant kidney or liver disease
  • Nervous system disorders, including multiple sclerosis or lupus
  • Pregnant or breastfeeding women
  • Current treatment with other biological medications (specialized drugs that target specific parts of immune system)
  • Blood disorders or significant abnormalities in blood tests
  • Uncontrolled high blood pressure or diabetes
  • Recent live vaccines (within 4 weeks before starting the study)
  • Participation in other clinical trials within the past 3 months
  • Alcohol or drug abuse within the past 6 months
  • Mental health conditions that could interfere with study participation
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Investigated drugs

  • MB04

    is a biosimilar medication being studied for treating rheumatoid arthritis. It is designed to work similarly to Enbrel in reducing joint inflammation and managing arthritis symptoms.

  • Enbrel

    (etanercept) is a medication used to treat rheumatoid arthritis by reducing inflammation in the joints. It works by blocking a substance in the body that causes inflammation.

  • Methotrexate

    is a medication commonly used to treat rheumatoid arthritis. It helps reduce pain, swelling, and stiffness in the joints by suppressing the immune system's inflammatory response.

What is already known about the treatment

  • Enbrel

    A prescription medication administered via subcutaneous injection that contains etanercept as its active ingredient and belongs to the class of biological disease-modifying antirheumatic drugs (bDMARDs). This medication works by blocking tumor necrosis factor (TNF), a protein responsible for causing inflammation in the body, making it effective in treating moderate to severe rheumatoid arthritis in combination with methotrexate. Enbrel has been extensively studied in clinical trials and is approved by both the FDA and EMA, demonstrating significant improvement in reducing joint pain, swelling, and preventing further joint damage in rheumatoid arthritis patients.

  • MB04

    A biosimilar medication to Enbrel (etanercept) that is being studied for the treatment of moderate to severe rheumatoid arthritis, administered through subcutaneous injection. Like Enbrel, it works by targeting and blocking TNF-alpha to reduce inflammation in the joints, and is designed to be used in combination with methotrexate. This biosimilar is currently undergoing clinical trials to demonstrate comparable efficacy, safety, and immunogenicity to the reference product Enbrel.

Investigated diseases

Rheumatoid Arthritis - A chronic inflammatory disease that primarily affects the joints throughout the body. The condition causes the immune system to mistakenly attack the body's own tissues, particularly the lining of joint capsules, leading to inflammation and swelling. Over time, this ongoing inflammation can cause thickening of the joint lining, destruction of cartilage and bone within the joint, and gradual loss of joint function. The disease typically affects multiple joints symmetrically, meaning if one hand is affected, the other usually is too. Rheumatoid arthritis commonly begins in the small joints of the hands and feet, but can spread to larger joints like knees, hips, and shoulders. The condition often develops gradually, with symptoms including joint pain, stiffness (especially in the morning), swelling, and warmth in affected areas.
Trial detailsLast updated 2 Oct 2026
Age18+ yearsPhasePhase IIITrial ID2024-510826-16-00Protocol codeMB04-C-01-23Estimated enrolment696 patientsSponsorMabxience Research S.L.

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