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Understanding The Stem Cell Transplantation Process
Graft-Versus-Host Disease (GVHD)
For patients who undergo allogeneic stem cell transplantation, one of the
most signicant risks is a complication known as graft-versus-host disease.
This is a common condition that occurs when the donor’s stem cells attack
the patient’s healthy cells, and it can range from a minor problem to a very
serious one. When it develops shortly after engraftment of the donated
cells, this complication is known as acute GVHD (aGVHD), whereas when
it develops or continues months or years after the transplant, it is called
chronic GVHD (cGVHD). The two forms were once considered the same
disease process occurring at different times, but now some doctors think of
cGVHD as a condition more like an autoimmune disease such as lupus or
rheumatoid arthritis.
To prevent GVHD, patients undergoing allogeneic stem cell transplantation
are given corticosteroids such as prednisone to suppress the immune cells
and keep them from attacking the patient’s healthy cells. Nevertheless, as
many as 30 to 70 percent of patients receiving an allogeneic transplant may
develop aGVHD, and 20 to 50 percent may experience cGVHD. An individual
patient may experience either, both, or neither forms of this condition, but
those who develop aGVHD are more likely to subsequently have cGVHD.
Both forms can affect many different areas of the body, including the skin,
liver, eyes, mouth, and digestive tract.
Treatment with traditional anticlotting medications is not a good option
because those drugs can cause severe bleeding. Historically, high doses of
corticosteroids and other immunosuppressants have been the primary
approach for treating GVHD as well as preventing it. However, long-term
immunosuppressant use has many serious potential side effects and risks,
including making the body very susceptible to life-threatening infections. In
addition, as many as 50 percent of cases of cGVHD do not resolve with
corticosteroids alone. For these patients, the only FDA-approved medication
for use as a secondline treatment for cGVHD is ibrutinib (Imbruvica), a
kinase inhibitor originally approved as a lymphoma treatment. Researchers
are now trying to determine whether combining ibrutinib with corticosteroids
for frontline treatment of cGVHD is more effective than corticosteroids alone.