Outcomes Following ATG Therapy for Chronic Lung Allograft Dysfunction

Background. Chronic lung allograft dysfunction (CLAD) is the major factor limiting survival post lung transplantation (LTx) with limited effective therapeutic options. We report our 12-y experience of antithymocyte globulin (ATG) as second-line CLAD therapy. Methods. Clinical and lung function data were collected on LTx patients receiving ATG. Rate of FEV1 decline (mL/d) was calculated before and after ATG. Partial response to ATG was defined by rate of FEV1 decline improving 20%. Complete response was defined by an absolute improvement or stability in baseline FEV1. Results. Seventy-six patients received ATG for CLAD. Of these, 5 patients who had a clinical diagnosis of antibody-mediated rejection and were treated with plasmapheresis before or after ATG were excluded from analysis. Sixteen (23%) were complete responders, 29 (40%) were partial responders, and 26 (37%) did not respond. Those with CLAD stage 2 or 3 and younger age were more likely to respond. Partial responders had a 65% lower risk of death or retransplant (HR, 0.35; P = 0.003), whereas complete responders reduced their risk by 70% (HR, 0.30; P = 0.006). Conclusions. ATG appears to stabilize or attenuate lung function decline in CLAD, which may lead to improved retransplant-free survival. Although certain predictors of response have been identified in this large single-center review, these findings need to be confirmed by a multicenter randomized-controlled trial to determine predictors of response to ATG for CLAD.