Calciphylaxis is a severe and progressive disease mainly seen in patients with end-stage kidney disease (when the kidneys have stopped working) undergoing haemodialysis. It involves the build-up of calcium in very small arteries resulting in a restricted blood supply and small clots. The skin develops ulcers that do not heal and usually cause severe pain. Calciphylaxis is a long-term debilitating and life-threatening condition, particularly due to the deep, painful, non-healing ulcers and the risk of infection. Calciphylaxis is a life-threatening condition. Once ulcerations develop, up to 80% of people with the condition will die, and just less than half will die within one year. Patients who do not die of sepsis or organ failure frequently undergo amputation of the involved limb.
Sodium thiosulfate is an injectable solution that is being developed to treat calciphylaxis-associated pain in patients undergoing dialysis. It is thought that sodium thiosulfate works by attaching itself to the calcium to form a compound that is removed from the body in the urine, reducing the build-up of calcium in the arteries. If licensed, this product will provide a treatment option for patients with calciphylaxis, who currently have few effective treatments available.