A Study to Assess the Efficacy and Safety of RO7790121 in Participants With Moderate to Severe Rheumatoid Arthritis Who Have Not Responded to or Who Cannot Tolerate Tumor Necrosis Factor (TNF) and/or Janus Kinase (JAK Inhibitors)

To join this study, you would typically need to be an adult aged 18 or over. You must have been diagnosed with rheumatoid arthritis for at least three months and your condition should be moderate to severe, meaning you have a certain number of swollen and tender joints at the time of screening. Crucially, you should have tried and not fully responded to, or not been able to tolerate, at least one of the standard rheumatoid arthritis medications known as a 'conventional synthetic disease-modifying antirheumatic drug' (csDMARD).

There are also some reasons why you wouldn't be able to take part. For example, if you've previously tried more than two TNF inhibitors or JAK inhibitors without success, you might not be eligible. If you have very severe rheumatoid arthritis (Class IV) or have used other types of biologic medications (apart from TNF inhibitors) or rituximab, you wouldn't qualify. You also couldn't have participated in another research study involving an experimental drug in the last few weeks.

Other reasons to not be eligible include having different types of arthritis, having had recent steroid injections, allergies to the study drug, recent major surgery, or serious ongoing health problems. A history of certain cancers (except for easily treated skin cancers or cervical cancer) or severe recurring infections would also prevent participation.

If you join this study, you'll be randomly assigned to either receive the new medication, Afimkibart, or a placebo (a dummy treatment). You won't know which one you're receiving, and neither will your study doctor, to keep the results fair. You'll have regular visits to the clinic where you'll have check-ups, blood tests, and assessments of your joints to see how your rheumatoid arthritis is progressing. You'll also be asked about any side effects you might experience. The total duration of your participation in the study involves a screening period, a treatment period, and a follow-up period after your last dose of medication. All study medication and doctor's visits related to the study will be provided at no cost.