A Study to Investigate Efficacy and Safety of AZD1163 in Participants With Rheumatoid Arthritis

This study is looking for adults aged 18 or older who have been diagnosed with rheumatoid arthritis for at least 12 weeks. Your RA symptoms should be at a moderate to severe level, meaning you have a certain number of swollen and tender joints, and blood tests show signs of inflammation. Importantly, you should have a specific type of antibody in your blood related to RA, called ACPA.

To be considered, you must have tried other RA treatments in the past, but they either didn't work well enough, stopped working, or you couldn't tolerate them. This includes at least one common RA medicine (like methotrexate) and/or one or two types of biologic medicines called TNF inhibitors. You also need to have been on your current regular RA treatment for at least 12 weeks and have been taking a stable dose for at least 4 weeks before joining.

However, you cannot join if you have another serious autoimmune condition that might make your RA diagnosis unclear, or if you're planning to take or are currently taking certain other biologic or targeted synthetic RA medications (apart from TNF inhibitors).

If you join the study, you'll first go through a screening period to check if you meet all the requirements. If you do, you'll be randomly assigned to one of four groups. Three groups will receive different doses of the new medicine, AZD1163, given as an injection under the skin. The fourth group will receive a 'placebo', which is a dummy injection with no active medicine. You will continue to take your usual RA medication alongside the study treatment.

The study medicine or placebo will be given until Week 24. After this, there will be a follow-up period of 28 weeks where researchers will continue to monitor your health and safety. The total duration of your participation, including screening, treatment, and follow-up, will be around 52 weeks (about a year). Throughout this time, you will have regular visits to the clinic for assessments, including physical exams, blood tests, and discussions about your symptoms and how you're feeling.