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