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A study testing RO7790121 for moderate to severe rheumatoid arthritis in patients who did not respond to or cannot tolerate TNF or JAK inhibitor treatments

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What is this trial about?

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

This study is looking at rheumatoid arthritis that is moderate to severe. Rheumatoid arthritis is a long-term condition where the body's defense system mistakenly attacks the joints, causing pain, swelling, and stiffness. The study will test a medication called RO7790121, which will be compared to placebo. This medication is given as an injection under the skin. Some people in the study will receive the actual medication while others will receive placebo. The people taking part will have rheumatoid arthritis that has not improved enough with previous treatments or they could not tolerate medicines called TNF inhibitors or JAK inhibitors.

The purpose of the study is to see if RO7790121 works better than placebo in reducing the activity of rheumatoid arthritis. The study will measure this by looking at changes in disease activity using a scoring system that includes C-reactive protein, which is a substance in the blood that shows inflammation levels. The main measurement will be taken at week 14 of the study.

During the study, participants will receive treatment and will be checked regularly to see how their rheumatoid arthritis is responding. The doctors will count how many joints are swollen and tender, and they will measure disease activity using different scoring methods. The study will also look at whether the treatment is safe by watching for any unwanted effects and checking blood tests and other health measurements. Blood samples will be taken at certain times to measure the amount of RO7790121 in the body.

The research process

The trial runs in 7 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Treatment period begins

    Upon joining the study, you will be assigned to receive either RO7790121 or a placebo. A placebo is an inactive substance that looks like the real medication but contains no active ingredient.

    The study is double-blind, which means neither you nor your doctor will know which treatment you are receiving during the study.

    The medication will be administered as a subcutaneous injection, meaning it will be injected under the skin.

  2. Step 2

    Regular treatment administration

    You will receive injections of either RO7790121 or placebo at scheduled intervals throughout the study.

    The exact dosage, frequency, and duration of injections will be determined according to the study protocol.

    You will need to attend scheduled visits to receive the injections and for monitoring purposes.

  3. Step 3

    Assessment at week 14

    At week 14, your disease activity will be assessed using several measurement tools.

    Your doctor will evaluate the Disease Activity Score-28 based on C-Reactive Protein levels. This score measures how active your rheumatoid arthritis is by looking at the number of swollen and tender joints, along with a blood test that measures inflammation.

    The number of swollen and tender joints will be counted to determine your response to treatment.

    Additional assessments will include measurements of joint inflammation and overall disease activity.

  4. Step 4

    Ongoing monitoring and assessments

    Throughout the study, you will be monitored for any side effects or adverse reactions to the treatment.

    Regular blood tests and other laboratory tests will be performed to check for any changes in your health.

    Your vital signs, such as blood pressure and heart rate, will be measured at scheduled visits.

    You will be asked to complete questionnaires about your quality of life and how you are feeling, including the SF-36 questionnaire, which assesses your physical and mental health.

  5. Step 5

    Additional response evaluations

    Your response to treatment will be evaluated using ACR response criteria. ACR stands for American College of Rheumatology, and these criteria measure improvement in your symptoms.

    ACR20, ACR50, and ACR70 responses will be assessed at week 14. These numbers represent 20%, 50%, and 70% improvement in your symptoms, respectively.

    Other disease activity scores will be measured, including DAS28-ESR, which uses a different blood marker called erythrocyte sedimentation rate to assess inflammation.

    SDAI and CDAI scores will also be calculated. These are simplified and clinical disease activity indexes that provide additional information about how active your arthritis is.

  6. Step 6

    Blood sample collection for medication levels

    Blood samples will be collected at specific times during the study to measure the concentration of RO7790121 in your bloodstream.

    These measurements help determine how the medication is processed by your body.

  7. Step 7

    Study completion

    The study will continue until all scheduled assessments and treatments are completed.

    Final evaluations will be performed to assess the overall effectiveness and safety of the treatment you received.

    Any ongoing side effects or health concerns will be documented and addressed.

Who can join the trial?

6 criteria

  • You must have moderate to severe active rheumatoid arthritis, which means your joints are inflamed and painful. This is confirmed by having at least 6 swollen joints and at least 6 tender joints at the beginning of the study.
  • You must agree to use proper birth control methods during the study as required.
  • You must have been diagnosed with rheumatoid arthritis for at least 3 months and meet specific medical classification criteria established by rheumatology organizations.
  • You must have previously tried at least one TNF inhibitor or JAK inhibitor, which are types of medications used to treat rheumatoid arthritis, and either did not respond well to them, stopped responding to them over time, or could not tolerate them due to side effects.
  • You must be an adult aged 18 years or older.
  • Both men and women can participate in this study.

Who cannot join the trial?

3 criteria

  • The source data does not provide specific exclusion criteria, which are reasons why a patient cannot participate in the study
  • Without detailed information about which conditions or situations would prevent participation, a complete list of exclusion criteria cannot be provided
  • Generally, clinical trials may exclude patients based on certain health conditions, medications they are taking, or other factors, but these specific details are not available in the provided information
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Investigated drugs

  • RO7790121

    is an investigational medication being tested for the treatment of moderate to severe rheumatoid arthritis. It is being studied in patients who have not responded well to or cannot tolerate previous treatments known as TNF inhibitors or JAK inhibitors. This medication is still being researched and is not yet approved for general use.

  • Placebo

    is an inactive substance that looks like the real medication but contains no active treatment. It is used in this study to compare against the investigational medication to help determine if the medication being tested actually works.

What is already known about the treatment

RO7790121 – RO7790121 is an experimental medication currently being studied in Phase II clinical trials for the treatment of moderate to severe rheumatoid arthritis, specifically in patients who have not responded well to or cannot tolerate previous treatments with TNF inhibitors or JAK inhibitors. This medication is administered to help reduce joint inflammation and disease activity in rheumatoid arthritis patients, as measured by improvements in a scoring system that tracks swollen joints, tender joints, and inflammation markers in the blood. While the exact mechanism of how RO7790121 works at the molecular level has not been fully disclosed in this trial information, it is being tested as a potential alternative treatment option for patients with difficult-to-treat rheumatoid arthritis who need new therapeutic approaches beyond currently available medications.

Investigated diseases

Rheumatoid Arthritis – Rheumatoid arthritis is a long-term condition where the body's immune system mistakenly attacks the joints, causing inflammation. It typically affects multiple joints on both sides of the body, most commonly the hands, wrists, and knees. The disease causes pain, swelling, and stiffness in the affected joints, which is often worse in the morning or after periods of rest. Over time, the ongoing inflammation can damage the joint tissues, including cartilage and bone. This damage can lead to reduced joint movement and changes in joint shape. The condition can also cause fatigue and may affect other parts of the body beyond the joints.
Trial detailsLast updated 7 Oct 2026
Age18+ yearsPhasePhase IITrial ID2025-521034-28-00Protocol codeWA45846Estimated enrolment186 patientsSponsorF. Hoffmann-La Roche AG

sourced from the EU Clinical Trials Register and site verification

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