This study is investigating a new medication being developed as a potential treatment for patients with complications due to Beta Thalassemia. Thalassemia causes abnormal haemoglobin (the protein in red blood cells that carries oxygen) and ineffective red blood cells to be produced by the body. A naturally occurring hormone called hepcidin is also suppressed, which in turn leads to increased absorption of iron in the gastrointestinal tract (the gut). This is sometimes referred to as iron overload. High levels of iron accumulate in the heart, liver and other body tissues which causes significant ongoing health problems and a shorter life expectancy. There are current treatments available to help treat iron overload (called chelators) but they are not completely effective, they can cause dysfunction in the body’s organs, and they are unpleasant to take. This new medication is similar to hepcidin and may therefore work to control iron absorption in the gut, and improve the production of red blood cells.