High Dose Cyclophosphamide for Treatment of Scleroderma

Scleroderma

High Dose Cyclophosphamide, Systemic Sclerosis, Scleroderma, immunoablation

Systemic Sclerosis (Scleroderma) varies greatly in clinical manifestations, mode of presentation, and course. The natural history of this chronic autoimmune disease ranges from benign to fatal. Patients are classified into limited and diffuse scleroderma defined by the degree of skin involvement. Patients with limited disease (e.g. the C.R.E.S.T. syndrome) generally have mild disease and normal survival. However, patients with diffuse cutaneous scleroderma often have severe multi-system disease that is not only devastating emotionally and physically but is associated with a 60-70% five year survival and a 40-50% 10 year survival. No therapies have proven effective in the treatment of scleroderma. Strategy to treat scleroderma have included attempts to prevent fibrosis with drugs that interfere with collagen metabolism, attempts to modify the disease process by immunosuppression and attempts to alter the disease by vasoactive drugs. High dose of corticosteroids and other immunosuppressive drugs (e.g. chlorambucil, 5-fluorouracil, methotrexate, cyclophosphamide, cyclosporine) used at conventional doses have not proven curative, but have shown some benefit for inflammatory features of the disease (e.g. arthritis, myositis, fibrosing alveolitis). Both allogeneic and autologous bone marrow transplantation (BMT) have shown to modify and in some instances reverse a variety of animal models of autoimmune disease. This has prompted many investigators to propose the use of peripheral blood stem cell transplantation (PBSCT) for the treatment of autoimmune disease including scleroderma. Unfortunately, this approach risks infusing untreated autoreactive lymphocyte clones after the immunoablative preparative regimen. We have previously demonstrated that high-dose cyclophosphamide without BMT can induce durable and complete remissions in another autoimmune disease, severe aplastic anemia. Recent data with high dose cyclophosphamide show that it can induce complete remissions in other autoimmune hematologic disorders. The objective of this study is to determine whether high dose cyclophosphamide can induce a durable remission in scleroderma patients with life-threatening disease, and to determine toxicity of high dose cyclophosphamide in high risk scleroderma patients.

Study design The study was an open-label, single-site trial of a single exposure to high-dose cyclophosphamide without stem cell rescue. Each patient was followed up by the same doctor to eliminate interobserver skin score variation. Baseline measurements included comprehensive laboratory studies that included complete blood count with differential, comprehensive metabolic panel, urine analysis with culture, quantitative immunoglobulins, antibodies to hepatitis B core and surface antigens and antibodies to hepatitis C, human immunodeficiency, herpes, varicella, Epstein-Barr viruses; rapid plasma reagin test, chest x-ray or high-resolution computed tomography (HRCT) scan of the lungs, pulmonary function testing, electrocardiogram, and echo or multigated acquisition (MUGA) scan. The primary clinical efficacy end point was the modified Rodnan skin score (mRSS).24 A 25% sustained improvement in the mRSS at any point in the follow-up was considered clinically important and a successful outcome.25 Secondary outcome measures included the Health Assessment Questionnaire-Disability Index (HAQ-DI) and physician global assessment (PGA) determined by a visual analogue scale on a scale from 0 to 100. Values for the percentage predicted lung volumes were referenced from NHANES/Hanikson et al26 and for diffusing capacity of the lungs for carbon monoxide (DLCO) from Knudson et al.27 The disease duration was defined as the time from the first non-Raynaud's symptom related to scleroderma to study entry. Treatment protocol Cyclophosphamide (50 mg/kg) was administered intravenously over 1 hour daily for four consecutive days (200 mg/kg total) through a Hickman catheter. The dose of cyclophosphamide was based on the ideal body weight as determined by the Metropolitan Life tables.28 29 If the patient's actual weight was less than the ideal body weight, the actual body weight was used to calculate the cyclophosphamide dose. Intravenous mesna (10 mg/kg) was given 30 minutes before cyclophosphamide and then 3, 6 and 8 hours after cyclophosphamide was administered for prophylaxis against haemorrhagic cystitis. Intravenous ondansetron (32 mg) was administered 1 hour before each dose of cyclophosphamide. Six days after the last dose of cyclophosphamide, all patients received granulocyte colony-stimulating factor (5 µg/kg/day) until the neutrophil count was 1×109/l for two consecutive days. Prophylactic antibiotic support, consisting of fluconazole (400 mg/day), norfloxacin (400 mg/day), and valaciclovir (500 mg twice a day, if antibodies to herpes simplex were present), was given beginning the day after the last dose of cyclophosphamide and continuing until the neutrophil count exceeded 0.5×109/l. Dapsone (100 mg three times a week for 6 months) or trimethoprim-sulfamethoxazole (80/400 mg three times a week for 6 months) was administered for Pneumocystis carinii prophylaxis. Packed red blood cell (leucocyte-poor) transfusions were administered to maintain a haematocrit level \>25%. Platelet transfusions were given for bleeding or to maintain a platelet count \>10×109/l, or both. All blood products were irradiated (\>2000 rad) to prevent graft versus host disease.

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