Long Term Effects of Cyclophosphamide Treatment on Lung Function and Survival in Scleroderma Patients with Interstitial Lung Disease

BACKGROUND: Scleroderma (SSc) patients with active interstitial lung disease (ILD) experience a decline in lung function and increased mortality; cyclophosphamide (CYC) therapy may stabilize lung function at one and two years follow-up. Long-term lung function and survival outcomes of SSc patients with ILD following CYC treatment remain largely unknown. METHODOLOGY: We reviewed records of SSc patients with active ILD who had received at least six months of CYC treatment and had pulmonary function tests (PFTs) performed at least two years from the onset of treatment. PRINCIPAL FINDINGS: Thirty eight patients meeting eligibility criteria had a mean follow-up period from start of CYC to the last follow-up PFT of 5.1 years (range 2.3 -10.8 years). At a median of 4.1 years (range 9 months - 8.4 years), 12/38 (32%) patients had a significant decline in % predicted Forced Vital Capacity from their baseline PFT. At a median of 3.9 years (range 7 months - 8.4 years); 12/36 (33%) patients experienced a significant decline in their % predicted carbon monoxide diffusing capacity. Three patients died at a follow-up between 4.5-6 years and two received bilateral lung transplants because of severe restrictive lung disease. CONCLUSIONS: While the majority of SSc patients treated with CYC for active ILD experience long-term lung function stability and survive, greater than 1/3 of patients will experience either lung function decline, death, or require a lung transplant. This suggests that despite aggressive immune suppressing therapy, a subset of patients will have continued lung function decline, highlighting the need for ongoing monitoring and better therapeutic options.