Phase II Pilot Study of Cyclophosphamide and Rabbit Anti-Thymocyte Globulin as Salvage Therapy in Patients With Diffuse Systemic Sclerosis

PROTOCOL ENTRY CRITERIA: --Disease Characteristics-- Diagnosis of diffuse systemic sclerosis Progressive disease Skin score at least 16 Interstitial or pulmonary vasculitis (FVC or DLCO no greater than 70% predicted) with evidence of alveolitis by bronchoalveolar lavage (BAL) Proteinuria (more than 500 mg/24 hours) Rapid deterioration in pulmonary function (at least 15% decrease in FVC or DLCO within the past 6 months) or new evidence of alveolitis by CT scan changes or BAL No acute renal failure secondary to systemic sclerosis crisis DLCO greater than 20% predicted Ineligible for or refused autologous or allogeneic peripheral blood stem cell or bone marrow transplantation --Prior/Concurrent Therapy-- Endocrine therapy: Concurrent prednisone allowed if prior chronic use Other: At least 4 days since prior immunosuppressive therapy --Patient Characteristics-- Performance status: Karnofsky 50-100% Hematopoietic: Absolute neutrophil count at least 1,500/mm3 Platelet count at least 100,000/mm3 Hepatic: Bilirubin less than 2.5 times upper limit of normal (ULN) SGOT less than 2.5 times ULN Renal: See Disease Characteristics Creatinine clearance at least 35 mL/min No requirement for renal dialysis Cardiovascular: Ejection fraction greater than 45% No myocardial infarction within the past 12 months No unstable angina No uncontrolled cardiac arrhythmias No evidence of congestive heart failure Pulmonary: See Disease Characteristics Other: Not pregnant Negative pregnancy test Fertile patients must use effective contraception HIV negative No active uncontrolled infection No hypersensitivity to rabbit proteins No prior hemorrhagic cystitis requiring transfusion No concurrent active hemorrhagic cystitis by cystoscopy (if prior history) No concurrent malignancy