Setrusumab vs Placebo for Osteogenesis Imperfecta

To be able to join this study, people must be aged between 5 and 25 years old and have a confirmed diagnosis of Osteogenesis Imperfecta (Type I, III, or IV) that's been identified through genetic testing. Participants should also have experienced at least one new bone fracture in the last year, or at least two fractures in the last two years, or at least one major bone fracture (in the shin, thigh, or upper arm) in the last two years.

Your vitamin D levels must be at a healthy level. If they are a bit low, you might be asked to take vitamin D supplements for a short time and have your levels checked again. It's also important that you are not currently taking bisphosphonate medication, and you must agree not to take it during the study. If you are female and able to have children, or a male whose partner could become pregnant, you'll need to use very effective contraception during and for a period after the study, and agree not to become pregnant or father a child.

Unfortunately, you wouldn't be able to join if you have certain other serious health issues, such as a history of bone cancer, or specific problems with your spine or brain (like Chiari malformation). The research team will review your full medical history to make sure everyone joining is suitable and safe.

If you decide to take part, you'll first have a screening visit to check if the study is right for you. If you qualify, you'll be assigned to receive either Setrusumab or a placebo. In some parts of the study, you might first receive different doses to help find the best one, and later everyone will have the chance to receive Setrusumab.

You'll have regular visits to the clinic where doctors and nurses will monitor your health, check for any changes in your bones, and see how you're feeling. These visits will likely involve physical exams, blood tests, and scans (like X-rays) to look at your bones. The study treatment will be given according to a set schedule, which the study team will explain fully. For some people, there's an optional sub-study that involves a small bone biopsy to get more detailed information, but this is entirely up to you.

Initially, some participants might receive the study treatment for about 6 months, and others for a longer period. After the main comparison period, you'll have the option to continue receiving Setrusumab open-label (meaning you'll know you're getting the active drug) for at least 12 months, and potentially until the medicine is available in your area. The total duration of your involvement could vary depending on the phase you are in and if you choose to continue into the extension period.