This study will look at how well a drug that reduced the amount of oxalate in the body works in patients that have kidney disease and need dialysis treatment. People with kidney disease often have higher levels of oxalate in the blood. People with kidney disease are also at higher risk of having heart attacks, heart disease and strokes (these are called cardiovascular diseases). It is thought that high oxalate levels may increase the risk of these diseases. This study will investigate if this medicine can lower the amount of oxalate in the blood of dialysis patients and see if there is any change in the health of their heart. This medicine is already used for people who have high oxalate levels because of a genetic cause and has been used safely for patients on dialysis. The study will put the participants randomly into either the group getting the study medicine or the group getting a placebo (this will be a solution of saline water). Neither participants not the doctors will know whether the drug or placebo is given until after the end of the study. At the start of the study all the participants will have an echocardiogram (an ultrasound of the heart) and again 6 months later at the end of the study. We will also take blood tests once a month when the participants come for dialysis.