A Phase III, Prospective, Multicenter, Randomized, Controlled Clinical Trial to Demonstrate the Efficacy and Safety of Liposomal Cyclosporine A (L-CsA) Inhalation Solution Delivered via the PARI Investigational eFlow® Device plus Standard of Care versus Standard of Care Alone in the Treatment of Chronic Lung Allograft Syndrome / Bronchiolitis Obliterans Syndrome in Patients post Double Lung Transplantation (BOSTON-2)


About this study

The purpose of this study is to evaluate L-CsA for the treatment of bronchiolitis obliterans syndrome in adults diagnosed with Bronchiolitis Obliterans Syndrome (BOS) following double-lung transplant. Patients will receive either L-CsA (5 mg) via the PARI Investigational eFlow® Device twice daily plus Standard of Care (SoC) treatment, or SoC alone, for a period of 48 weeks. All patients will be eligible to continue in an open-label extension trial of L-CsA following completion of BOSTON-2.

Participation eligibility

Participant eligibility includes age, gender, type and stage of disease, and previous treatments or health concerns. Guidelines differ from study to study, and identify who can or cannot participate. There is no guarantee that every individual who qualifies and wants to participate in a trial will be enrolled. Contact the study team to discuss study eligibility and potential participation.

Inclusion Criteria:

  • Adult patients ≥ 18 years who received a single lung transplant at least 12 months prior to Screening.
  • Patients with clinically defined BOS (CLAD - BOS phenotype) with screening FEV1 between 85-60% of personal best FEV1 value post-transplant.
  • Patients with an FEV1/FVC ratio of 2.5 mg/dL, or requiring chronic dialysis. 1
  • Patients in whom the diagnosis of BOS has been confirmed by the elimination of other possible causes of obstructive lung disease.
  • Patients with a diagnosis of BOS made at least 1 year after transplant surgery and within 12 months prior to the Screening Visit.
  • Patients should be on a three-drug maintenance regimen of immunosuppressive agents including tacrolimus, a second agent such as but not limited to MMF or azathioprine, and a systemic corticosteroid such as prednisone. The regimen must be stable for at least 4-weeks prior to Randomization with respect to the therapeutic agents.
  • Patients must consent to retrieve prespecified data from the historic medical record (e.g., information related to the transplant surgery; spirometry data; medication use).
  • Patients must be receiving or have received post-transplant prophylaxis against Cytomegalovirus (CMV) and Pneumocystis pneumonia as per SoC at the site.
  • Patients capable of understanding the purposes and risks of the clinical trial, who have given written informed consent and agree to comply with the clinical trial requirements/visit schedules, and who are capable of aerosol inhalation.
  • Women of childbearing potential must have a negative serum or urine pregnancy test within 7 days prior to randomization and must agree to use one of the methods of contraception listed in Appendix II of the protocol through their End of Study Visit.
  • Patients have no concomitant diagnoses that are considered fatal within one year (12 months) of Screening.

Exclusion Criteria:

  • Patients with confirmed other causes for loss of lung function, such as acute infection, acute rejection, restrictive allograft syndrome (RAS), etc.
  • Patients with Cystic Fibrosis.
  • Patients with acute antibody-mediated rejection at Screening. In this context, clinically stable patients displaying low and stable levels of donor-specific antibodies (DSA) at the Screening Visit (as judged by the Investigator) are eligible for the study.
  • Active acute bacterial, viral, or fungal infection not successfully resolved at least 4 weeks prior to the Screening Visit. Patients with chronic infection or colonization who are clinically stable as per judgement of the Investigator are eligible for the study.
  • Mechanical ventilation within 12 weeks prior to Randomization.
  • Patients with uncontrolled hypertension.
  • Patient has baseline resting oxygen saturation of < 89% on room air or use of supplemental oxygen.
  • Evidence of functional airway stenosis (e.g., bronchomalacia/tracheomalacia, airway stents, or airways requiring balloon dilatations to maintain patency) with onset after the initial diagnosis of BOS and ongoing at Screening and/or Randomization Visit.
  • Known hypersensitivity to L-CsA or to cyclosporine A.
  • Patients with chronic renal failure, defined as serum creatinine > 2.5 mg/dL, or requiring chronic dialysis.
  • Patients with liver disease and serum bilirubin > 3-fold upper limit of normal range or transaminases > 2.5 upper limit of normal range.
  • Patients with active malignancy within the previous 2 years, including post-transplant lymphoproliferative disorder, with the exception of treated, localized basal and squamous cell carcinomas. 
  • Pregnant women or women who are unwilling to use appropriate birth control to avoid pregnancy through their End of Study Visit. 
  • Women who are currently breastfeeding. 
  • Receipt of an investigational drug as part of a clinical trial within 4 weeks prior to the Screening Visit. This is defined as any treatment that is implemented under an Investigational New Drug (IND) or compassionate use.
  • Patients who have received extracorporeal photophoresis (ECP) for treatment of BOS within 1 month prior to Randomization. 
  • Patients who are currently participating in an interventional clinical trial. 
  • Psychiatric disorders or altered mental status precluding understanding of the informed consent process and/or completion of the necessary procedures. 
  • Any co-existing medical condition that in the Investigator's judgment will substantially increase the risk associated with the patient's participation in the clinical trial.

Participating Mayo Clinic locations

Study statuses change often. Please contact the study team for the most up-to-date information regarding possible participation.

Mayo Clinic Location Status Contact

Jacksonville, Fla.

Mayo Clinic principal investigator

Si Pham, M.D.

Open for enrollment

Contact information:

Si Pham M.D.



More information


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