Pirfenidone for Restrictive Chronic Lung Allograft Dysfunction

Despite advances in lung transplantation, median survival remains only 55% at 5 years. The primary cause of death is chronic lung allograft dysfunction (CLAD), occurring in 43% of recipients at 5 years. Recently, it has been recognized that CLAD can have an obstructive (BOS) or a restrictive (RCLAD) phenotype, also known as restrictive allograft syndrome (RAS), and that both may coexist. These phenotypes differ not only in their spirometric, radiographic and histologic features but also in their rates of progression and survival. Thus, there is a critical need to find therapies other than re-transplantation, which remains the only effective therapeutic option and explore the pathobiology driving RCLAD. RCLAD shares features with Idiopathic Pulmonary Fibrosis (IPF), including its progressive and lethal course, extracellular matrix deposition, architectural distortion, fibroblast proliferation, and short telomeres in lung epithelial cells. These common features suggest RCLAD and IPF may share molecular pathogenesis. As a result, some have explored using FDA approved anti-fibrotic medications for IPF in RCLAD in case reports. This proposal aims to gather the preliminary data needed to design a multicenter randomized controlled trial (RCT) of pirfenidone for RCLAD. To do so, the investigators first need evidence of tolerability, to understand drug interactions with the immunosuppressive regimen used to maintain allograft function and early evidence that pirfenidone may slow FVC decline and radiographic progression in RCLAD. Evidence that pirfenidone is well tolerated in transplant recipients and that it slows the progression of RCLAD would be paradigm shifting. Further, identifying subjects at risk for RCLAD before the onset of spirometric changes would allow to start therapeutic interventions sooner, maximizing their benefit. Finding biomarkers that predict response to pirfenidone would identify patients most likely to benefit.