Graft versus Host Disease (GVHD)
Transplantation of allogeneic (donor-derived) blood stem cells is a widely accepted medical procedure to restore normal blood cell production (hematopoiesis) in patients treated for blood- or lymphatic cancers, or otherwise suffering from defective blood formation, or immunity. More and more patients receive such a transplant every year.
For successful transplantation, the blood stem cell graft must contain a minimum number of donor-derived T cells (immune cells). These can be beneficial in fighting any residual cancer cells - the Graft versus Leukemia (GVL) effect. However, sometimes they can attack the normal tissues of the patient, causing Graft versus Host Disease (GVHD). It is thought that these immune processes are closely linked. Approximately 25% of blood stem cell transplant patients develop severe acute GVHD that does not respond adequately to standard first-line therapy. And this number is expected to grow substantially as the number of patients receiving high risk transplants from unrelated donors is expected to double in the next five years.
GVHD is thought to be developed in several steps. Firstly, prior chemotherapy, or radiotherapy may create damage and inflammation to the patient’s gastrointestinal tract, liver and blood vessels, priming the environment and triggering donor-derived T cells to recognize their new host as ‘foreign’ and start an immune reaction. This reaction, in turn, activates additional players in the immune system, such as monocytes, macrophages and NK cells, resulting in further host tissue damage. Severe acute GVHD causes blistering of the skin, liver failure and severe diarrhea. It has a poor prognosis with 5-25% survival rates after five years depending on severity.
Standard first-line therapy for acute GVHD is corticosteroids (1-2mg/kg/day), which helps approximately 50% of patients. The rest rely on experimental therapies, such as Anti -Thymocyte Globulin (ATG), Campath® (Alemtuzumab), Anti-Cytokine or Anti-Cytokine-Receptor Antibodies, Extracorporeal Photopherisis or Mesenchymal Stem Cell Therapy. So far, no other experimental therapy has proved as promising as T-Guard™.
Why is T-Guard So Promising?
The results of the initial studies into T-Guard are considered highly encouraging. Treatment with T-Guard took just one week and yielded statistically significant results that were made particularly important because the patients did not respond to any other treatment. T-Guard worked safely, quickly, effectively and generated long-lasting benefits, indicating that it can ‘reset’ the immune system. Its unique formulation enables synergistic activity and narrowly-targeted specificity and involves several gentle mechanisms of action. Its speed of action and short half-life also contribute towards the absence of toxicity as seen in testing.