Ibrutinib is in clinical development for chronic graft versus host disease (cGvHD). After a donor stem cell transplant, the donor’s stem cells (the graft) may sometimes react against the host’s own cells. This is called Graft versus Host Disease (GvHD). cGvHD may happen more than three months after transplant. The symptoms depend on which parts of the body are affected. They may include skin changes, hair that grows slowly, feeling short of breath or wheezy, dry and swollen mouth and mouth ulcers, dry, gritty eyes, diarrhoea, stomach cramps, sickness and loss of appetite, vaginal narrowing and dryness, repeated infections, and muscle weakness and joint pain. Current standard treatment includes the use of steroids but this is often associated with significant side effects.
Ibrutinib belongs to class of drugs called Bruton’s Tyrosine Kinase (BTK) inhibitors that work against defective B lymphocytes, which are a type of white blood cells affected by these diseases. Earlier studies have demonstrated that ibrutinib works by blocking the BTK signalling pathway, resulting in reduced production of the defective blood cells in GvHD and some other types of blood cancers. Ibrutinib is available as tablets and taken orally. If licensed, ibrutinib will offer an additional first line treatment option for cGvHD which may improve patients’ quality of life by helping reduce the dose of steroids used and reduce the severity of GvHD symptoms.