REPLACE - A multi-centre, randomised, double-blinded, placebo controlled 16-weeks study to compare the effect of hydrocortisone and placebo in patients with Giant Cell Arteritis (GCA)/ Polymyalgia Rheumatica (PMR) with patient-reported symptoms of adrenal insufficiency after cessation of glucocorticoid treatment.

This study, called REPLACE, is looking into an important health concern for people who have conditions like Giant Cell Arteritis (GCA) or Polymyalgia Rheumatica (PMR). These conditions are often treated with steroid medications like prednisolone. While these steroids are very effective, when patients stop taking them, some can experience something called 'adrenal insufficiency'. This happens because the body has gotten used to the steroid medication doing the work, and it can take time for your own body to start producing enough of its natural steroids again. This can lead to symptoms like tiredness, weakness, and feeling generally unwell.

The REPLACE study wants to see if a specific type of steroid tablet, called hydrocortisone, can help people feel better if they have these symptoms after stopping their main steroid treatment for GCA or PMR. Hydrocortisone is a medication that's already approved and used for other health issues. In this study, some people will receive the hydrocortisone tablets, and others will receive a 'placebo' – which looks exactly like the hydrocortisone tablet but contains no active medicine. This helps researchers understand if the hydrocortisone is truly making a difference.

The trial will last for 16 weeks, and throughout this time, the research team will carefully track how participants are feeling. They will primarily use questionnaires to understand changes in symptoms related to adrenal insufficiency, but they will also look at other factors like tiredness, overall quality of life, blood pressure, and bone health. This research is important because it could help doctors find better ways to support patients who are recovering after stopping long-term steroid therapy.