Study to Evaluate the Safety and Tolerability of Camizestrant in Combination With Atirmociclib in Women With Advanced Breast Cancer

To join this study, you need to be a woman aged 18 or older with advanced breast cancer that has spread or come back. Your doctors must have confirmed that your cancer is ER-positive and HER2-negative, and it must have grown or gotten worse after your last treatment. Importantly, you must have previously received treatment with a CDK4/6 inhibitor.

You also need to be well enough to take part, meaning you can mostly look after yourself. Your doctors will check if there's at least one part of your cancer that can be measured accurately, usually with scans like CT or MRI. If you're a woman who could still have children, you'll need to agree to use effective contraception. If you're pre-menopausal, you'll also need to be on specific hormone therapy (GnRH agonist) before and during the study.

There are also some reasons why you couldn't join. For example, if you've already had two or more treatments with CDK4/6 inhibitors for your advanced cancer, or if you've previously taken the specific study drugs (Camizestrant or Atirmociclib). You also can't have been treated with similar experimental drugs that block oestrogen or different types of CDK inhibitors.

If you join this study, your journey will be divided into different periods. First, there's a 'screening period' where doctors will do tests to make sure you're a good fit for the study. Then, you'll have a short period where you'll receive a single dose of Atirmociclib on its own. After that, you'll enter the 'doublet intervention period', which is when you'll take both Camizestrant and Atirmociclib together as instructed by the doctors. This is an 'open-label' study, meaning you and your doctors will know which drugs you are taking.

Throughout these periods, doctors will regularly monitor your health, how you're feeling, and check for any side effects. They'll also perform scans (like CT or MRI) to see how the cancer is responding to the treatment. There will be regular blood tests to understand how the drugs are working in your body. Once your treatment period ends, there will be a 'post-treatment follow-up period', where staff will continue to check on your health and progress, even after you've stopped taking the study drugs. The total duration of your involvement will depend on how you respond to the treatment and the study's follow-up plan.