HSCT provides a potentially curative option for some types of cancer, but it comes with the risk of GVHD. GVHD occurs when the transplanted immune system attacks the recipient’s body and is the leading cause of non-cancer death in stem cell transplant recipients. Roughly half of HSCT recipients develop GVHD.
There are two kinds of GVHD, acute (aGVHD) and chronic (cGVHD). Onset of aGVHD is typically within the first 100 days post-transplant and occurs in 30 – 70% of transplant recipients. Half of those individuals will go on to develop cGVHD, and an additional 30 – 70% develop cGVHD independently.
GVHD significantly increases the chance of death or serious complications. Five-year survival in those who respond to standard of care steroid treatment is only 53%. Mortality in those who do not respond to steroids is as high as 95%.
GVHD is caused by the activation and trafficking of pathogenic T cells, which then go on to attack healthy tissue. Itolizumab, which is designed to treat GVHD by preventing this aberrant T cell activity, is currently being evaluated in a clinical trial.