Extracorporeal Photopheresis (ECP) Treatment Overview

Extracorporeal photopheresis (ECP) is a treatment for graft-versus-host disease (GVHD) and  blood cancers that affect the skin. ECP is mainly used to treat GVHD cases that haven’t gotten better after steroid treatment. During ECP, your blood is collected and treated in a machine before being returned to you. While the exact way in which ECP works is still being studied, it’s believed to be successful by easing inflammation with fewer adverse side effects compared to other treatment options.

Blood stem cell transplant recipients who begin experiencing signs and symptoms of GVHD normally start with a steroid treatment. If steroids don’t work, your doctor may ask you to consider ECP treatment. Compared to steroids, ECP carries a lower risk of infection, but requires a longer treatment period.

If your care team recommends ECP, it helps to know what the treatment involves and how to prepare. While ECP is generally well tolerated, there are a few important factors to consider before getting started.

During each ECP session, your blood is drawn and passed through a specialized machine. The machine separates out your white blood cells, treats them with a light-sensitizing medication, and then exposes them to ultraviolet (UV) light. Once treated, these cells are returned to your bloodstream, where they may help reduce inflammation and ease GVHD symptoms.

• Reliable IV access – through large veins or a central line. If your veins are small or difficult to access, your doctor may recommend a central venous catheter (a thin tube placed in a large chest vein) to make treatment easier and more comfortable.
• Time for ongoing treatment – Each ECP session takes between 2 to 4 hours. Most people receive treatments weekly, then biweekly and then monthly. The overall duration depends on how your body responds—many people continue for several months or longer. Your doctor will typically reassess your progress after 2 to 3 months.
• Healthy blood counts – You’ll need enough red blood cells and platelets to safely receive treatment. If your counts are too low, your care team may postpone ECP or recommend a blood transfusion to support your recovery.

Most people tolerate ECP well, and side effects are usually mild.

• During treatment, you may feel lightheaded, cold or experience mild cramping.
• After treatment, some people have low-grade fevers, chills or flu-like symptoms for a day or two.
• Long-term, ECP may cause fatigue or anemia with extended use. Your care team can recommend iron supplements or transfusions if needed.
• You may be more sensitive to sunlight for 24 hours after each session. Use sunscreen and wear UV-protective sunglasses.

Let your doctor know if any side effects persist or feel unusual.

Call your doctor or care team right away if you experience:

• Swelling in your arm or shortness of breath (especially if you have a central line)
• Fever, chills or feeling unwell within 1–2 days of treatment
• GVHD symptoms that get worse, not better

ECP is a specialized therapy and may not be fully covered by all insurance plans. Your transplant center or financial counselor can help you understand your benefits, estimate out-of-pocket costs and explore support programs.

If you're looking for more GVHD treatment options, clinical trials may offer access to new therapies. The Jason Carter Clinical Trials Search and Support Program helps patients explore and join trials designed to improve outcomes after transplant.