Early extracorporeal photopheresis treatment is associated with better survival in patients with chronic or recurrent acute lung allograft dysfunction.

BACKGROUND: Due to development of chronic lung allograft dysfunction (CLAD), prognosis for patients undergoing lung transplantation (LTx) is still worse compared to other solid organ transplant recipients. Treatment options for slowing down CLAD progression are scarce with extracorporeal photopheresis (ECP) as an established rescue therapy. The aim of the study was to identify characteristics of responders and non-responders to ECP treatment, assess their survival, lung function development and by that define the subset of patients who should receive early ECP treatment. METHODS: We performed a retrospective study of all LTx patients receiving ECP treatment at the University Hospital Zurich between January 2010 and March 2020. Patients were followed-up for a maximum period of 5 years. Mortality and lung function development were assessed by CLAD stage and by CLAD subtype before initiation of ECP treatment. RESULTS: Overall, 105 patients received at least one ECP following LTx. A total of 57 patients (61.3%) died within the study period with a median survival of 15 months. Mortality was 57% for patients who started ECP at CLAD1, 39% for CLAD2, 93% for CLAD3, and 90% for CLAD4 (p < 0.001). Survival and lung function development was best in young patients at early CLAD stages 1 and 2. Response to ECP treatment was worst in patients with CLAD-RAS/mixed subtype (14.3%) and patients with ECP initiation in CLAD stages 3 (7.1%) and 4 (11.1%). Survival was significantly better in a subset of patients with recurrent acute allograft dysfunction and earlier start of ECP treatment (105 vs 15 months). CONCLUSION: In this retrospective analysis of a large group of CLAD patients treated with ECP after LTx, early initiation of ECP was associated with better long-term survival. Besides a subset of patients suffering of recurrent allograft dysfunction, especially a subset of patients defined as responders showed an improved response rate and survival, suggesting that ECP should be initiated in early CLAD stages and young patients. ECP might therefore prevent long-term disease progression even in patients with CLAD refractory to other treatment options and thus prevent or delay re-transplantation.

Influence of mycophenolate mofetil dosage and plasma levels on the occurrence of chronic lung allograft dysfunction in lung transplants: a retrospective cohort analysis.

INTRODUCTION: Development of chronic lung allograft dysfunction is a limiting factor for post-lung transplant survival. We evaluated whether the dose of the immunosuppressant mycophenolate mofetil or plasma concentrations of the active metabolite mycophenolic acid affect the development of chronic lung allograft dysfunction. METHODS: In this retrospective cohort study we recruited 71 patients with a lung transplant between 2010 and 2014 which survived the first year after transplantation up to 1 July 2021. An event-time-analytical Cox proportional-hazards regression model with time-varying-covariates (18,431 measurements for MPA, mycophenolate mofetil dosage, lymphocytes) was used to predict chronic lung allograft dysfunction, with adjustment for sociodemographic factors and lung function at baseline. RESULTS: 37 patients did not develop chronic lung allograft dysfunction (age 41.3 ± 15.6 years, baseline FEV1 95.5 ± 19.1% predicted) and 34 patients developed chronic lung allograft dysfunction (age 50.9 ± 13.3 years, baseline FEV1 102.2 ± 25.4% predicted). Mean mycophenolic acid did not differ significantly between the groups (2.8 ± 1.7 and 3.0 ± 2.3 mg/l; p = 0.724). In the first 4 post-transplant years the death rate was 25%. A total of 50% of the patients died by the ninth post-transplant year. There was a dose-effect relationship between mycophenolate mofetil dosage, mycophenolic acid (r2 = 0.02, p <0.001), as well as lymphocyte levels (r2 = -0.007, p <0.001), but only the traditional risk factor age predicted chronic lung allograft dysfunction. Continuously measured mycophenolic acid did not predict chronic lung allograft dysfunction (hazard ratio 0.98, 95% confidence interval 0.90-1.06, p = 0.64 over a period of 382.97 patient-years). CONCLUSION: Mycophenolate mofetil dosage and mycophenolic acid were not associated with chronic lung allograft dysfunction development. Thus, the mycophenolate mofetil dose or mycophenolic acid plasma concentration are not a primary factor related to organ rejection, but chronic lung allograft dysfunction may be influenced by other components of immunosuppression or other factors.