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.

Inclusion criteria

• Subject who underwent bilateral lung transplantation at University of California San Francisco (UCSF) and have a diagnosis of RCLAD based on the International Heart and Lung Transplant (ISHLT) classification. The diagnosis of RCLAD is based on spirometry (Forced Expiratory Volume in 1 second (FEV1) ≤ 80% and FVC ≤ 80% of best post-transplant baseline) and CT scan (e.g. pleuroparenchymal fibroelastosis) findings.

Exclusion criteria

• FVC decline related to non-RCLAD causes (e.g. pulmonary edema, pleural effusion, etc).
• Patients with any severe comorbidity complicating RCLAD which might determine their prognosis and functional level (e.g. active malignant disease) within the last 12 months
• Patients who have resumed smoking after transplantation
• Renal insufficiency (creatinine clearance < 30 ml/min calculated by the CKD-Epi formula)
• Total bilirubin above the upper limit of the normal range (ULN)
• Aspartate or alanine aminotransferase (AST or ALT) > 3 times the ULN.
• Known allergy of hypersensitivity to Pirfenidone
• Pregnancy
• Ongoing use or expected use of any of the following therapies:
• Strong inhibitors of CYP1A2 (e.g. fluvoxamine or enoxacin).
• Moderate inhibitors of CAYP1A2 (e. g. mexiletine, thiabendazole, or phenylpropanolamine). Ciprofloxacin will be allowed only at doses equal or less than 500 mg BID.
• Inability to provide informed consent.