Extracorporeal photophoresis: an evidence-based analysis.

OBJECTIVE

To assess the effectiveness, safety and cost-effectiveness of extracorporeal photophoresis (ECP) for the treatment of refractory erythrodermic cutaneous T cell lymphoma (CTCL) and refractory chronic graft versus host disease (cGvHD).

BACKGROUND

CUTANEOUS T CELL LYMPHOMA: Cutaneous T cell lymphoma (CTCL) is a general name for a group of skin affecting disorders caused by malignant white blood cells (T lymphocytes). Cutaneous T cell lymphoma is relatively uncommon and represents slightly more than 2% of all lymphomas in the United States. The most frequently diagnosed form of CTCL is mycosis fungoides (MF) and its leukemic variant Sezary syndrome (SS). The relative frequency and disease-specific 5-year survival of 1,905 primary cutaneous lymphomas classified according to the World Health Organization-European Organization for Research and Treatment of Cancer (WHO-EORTC) classification (Appendix 1). Mycosis fungoides had a frequency of 44% and a disease specific 5-year survival of 88%. Sezary syndrome had a frequency of 3% and a disease specific 5-year survival of 24%. Cutaneous T cell lymphoma has an annual incidence of approximately 0.4 per 100,000 and it mainly occurs in the 5(th) to 6(th) decade of life, with a male/female ratio of 2:1. Mycosis fungoides is an indolent lymphoma with patients often having several years of eczematous or dermatitic skin lesions before the diagnosis is finally established. Mycosis fungoides commonly presents as chronic eczematous patches or plaques and can remain stable for many years. Early in the disease biopsies are often difficult to interpret and the diagnosis may only become apparent by observing the patient over time. The clinical course of MF is unpredictable. Most patients will live normal lives and experience skin symptoms without serious complications. Approximately 10% of MF patients will experience progressive disease involving lymph nodes, peripheral blood, bone marrow and visceral organs. A particular syndrome in these patients involves erythroderma (intense and usually widespread reddening of the skin from dilation of blood vessels, often preceding or associated with exfoliation), and circulating tumour cells. This is known as SS. It has been estimated that approximately 5-10% of CTCL patients have SS. Patients with SS have a median survival of approximately 30 months. CHRONIC GRAFT VERSUS HOST DISEASE: Allogeneic hematopoietic cell transplantation (HCT) is a treatment used for a variety of malignant and nonmalignant disease of the bone marrow and immune system. The procedure is often associated with serious immunological complications, particularly graft versus host disease (GvHD). A chronic form of GvHD (cGvHD) afflicts many allogeneic HCT recipients, which results in dysfunction of numerous organ systems or even a profound state of immunodeficiency. Chronic GVHD is the most frequent cause of poor long-term outcome and quality of life after allogeneic HCT. The syndrome typically develops several months after transplantation, when the patient may no longer be under the direct care of the transplant team. Approximately 50% of patients with cGvHD have limited disease and a good prognosis. Of the patients with extensive disease, approximately 60% will respond to treatment and eventually be able to discontinue immunosuppressive therapy. The remaining patients will develop opportunistic infection, or require prolonged treatment with immunosuppressive agents. Chronic GvHD occurs in at least 30% to 50% of recipients of transplants from human leukocyte antigen matched siblings and at least 60% to 70% of recipients of transplants from unrelated donors. Risk factors include older age of patient or donor, higher degree of histoincompatibility, unrelated versus related donor, use of hematopoietic cells obtained from the blood rather than the marrow, and previous acute GvHD. Bhushan and Collins estimated that the incidence of severe cGvHD has probably increased in recent years because of the use of more unrelated transplants, donor leukocyte infusions, nonmyeloablative transplants and stem cells obtained from the blood rather than the marrow. The syndrome typically occurs 4 to 7 months after transplantation but may begin as early as 2 months or as late as 2 or more years after transplantation. Chronic GvHD may occur by itself, evolve from acute GvHD, or occur after resolution of acute GvHD. The onset of the syndrome may be abrupt but is frequently insidious with manifestations evolving gradually for several weeks. The extent of involvement varies significantly from mild involvement limited to a few patches of skin to severe involvement of numerous organ systems and profound immunodeficiency. The most commonly involved tissues are the skin, liver, mouth, and eyes. Patients with limited disease have localized skin involvement, evidence of liver dysfunction, or both, whereas those with more involvement of the skin or involvement of other organs have extensive disease.

TREATMENT

CUTANEOUS T CELL LYMPHOMA: The optimal management of MF is undetermined because of its low prevalence, and its highly variable natural history, with frequent spontaneous remissions and exacerbations and often prolonged survival. Nonaggressive approaches to therapy are usually warranted with treatment aimed at improving symptoms and physical appearance while limiting toxicity. Given that multiple skin sites are usually involved, the initial treatment choices are usually topical or intralesional corticosteroids or phototherapy using psoralen (a compound found in plants which make the skin temporarily sensitive to ultraviolet A) (PUVA). PUVA is not curative and its influence on disease progression remains uncertain. Repeated courses are usually required which may lead to an increased risk of both melanoma and nonmelanoma skin cancer. For thicker plaques, particularly if localized, radiotherapy with superficial electrons is an option. "Second line" therapy for early stage disease is often topical chemotherapy, radiotherapy or total skin electron beam radiation (TSEB). Treatment of advanced stage (IIB-IV) MF usually consists of topical or systemic therapy in refractory or rapidly progressive SS. Bone marrow transplantation and peripheral blood stem cell transplantation have been used to treat many malignant hematologic disorders (e.g., leukemias) that are refractory to conventional treatment. Reports on the use of these procedures for the treatment of CTCL are limited and mostly consist of case reports or small case series. CHRONIC GRAFT VERSUS HOST DISEASE: Patients who develop cGvHD require reinstitution of immunosuppressive medication (if already discontinued) or an increase in dosage and possibly addition of other agents. The current literature regarding cGvHD therapy is less than optimal and many recommendations about therapy are based on common practices that await definitive testing. Patients with disease that is extensive by definition but is indolent in clinical appearance may respond to prednisone. However, patients with more aggressive disease are treated with higher doses of corticosteroids and/or cyclosporine. Numerous salvage therapies have been considered in patients with refractory cGvHD, including ECP. Due to uncertainty around salvage therapies, Bhushan and Collins suggested that ideally, patients with refractory cGvHD should be entered into clinical trials. Two Ontario expert consultants jointly estimated that there may be approximately 30 new erythrodermic treatment resistant CTCL patients and 30 new treatment resistant cGvHD patients per year who are unresponsive to other forms of therapy and may be candidates for ECP. Extracorporeal photopheresis is a procedure that was initially developed as a treatment for CTCL, particularly SS. CURRENT TECHNIQUE: Extracorporeal photopheresis is an immunomodulatory technique based on pheresis of light sensitive cells. Whole blood is removed from patients followed by pheresis. Lymphocytes are separated by centrifugation to create a concentrated layer of white blood cells. The lymphocyte layer is treated with methoxsalen (a drug that sensitizes the lymphocytes to light) and exposed to UVA, following which the lymphocytes are returned to the patient. Red blood cells and plasma are returned to the patient between each cycle. Photosensitization is achieved by administering methoxsalen to the patient orally 2 hours before the procedure, or by injecting methoxsalen directly ino the leucocyte rich fraction. The latter approach avoids potential side effects such as nausea, and provides a more consistent drug level within the machine. In general, from the time the intravenous line is inserted until the white blood cells are returned to the patient takes approximately 2.5-3.5 hours. For CTCL, the treatment schedule is generally 2 consecutive days every 4 weeks for a median of 6 months. For cGvHD, an expert in the field estimated that the treatment schedule would be 3 times a week for the 1(st) month, then 2 consecutive days every 2 weeks after that (i.e., 4 treatments a month) for a median of 6 to 9 months.

REGULATORY STATUS

The UVAR XTS Photopheresis System is licensed by Health Canada as a Class 3 medical device (license # 7703) for the "palliative treatment of skin manifestations of CTCL." It is not licensed for the treatment of cGvHD. UVADEX (sterile solution methoxsalen) is not licensed by Health Canada, but can be used in Canada via the Special Access Program. (Personal communication, Therakos, February 16, 2006) According to the manufacturer, the UVAR XTS photopheresis system licensed by Health Canada can also be used with oral methoxsalen. (Personal communication, Therakos, February 16, 2006) However, oral methoxsalen is associated with side effects, must be taken by the patient in advance of ECP, and has variable absorption in the gastrointestinal tract. (ABSTRACT TRUNCATED)