Comparison of extracorporeal photopheresis efficacy in treated versus non-treated patients with refractory BOS

Background: Bronchiolitis obliterans syndrome (BOS) remains the main limitation for long-term survival after a lung transplantation. Several studies showed promising results regarding extracorporeal photopheresis (ECP) efficacy in BOS management. We aimed to compare, among recipients with BOS, the FEV1 evolution in ECP-treated patients to non-ECP treated patients. Methods: In this retrospective monocentric study, 25 patients with BOS were included after receiving an optimized treatment. Twelve patients with refractory BOS were treated with ECP. Among control patients not treated with ECP (n=13), 6 showed a persistent decline but did not undergo ECP for various reasons. Results: ECP stabilized pre-ECP lung function decline in the subsequent 6 to 24 months (Repeated measures one-way Anova–p=0.002) without any significant impact of FEV1 decline speed prior ECP nor the time between BOS diagnosis and ECP onset. There was a positive correlation between the monthly FEV1 gain and BOS stage severity within the first 6 months after ECP onset (p=0.09)(Figure 1A). ECP-treated patients showed a similar risk of additional permanent drop in FEV1 of 20% or higher after BOS onset compared to controls, but a lower risk when compared to control decliners (p=0.05) (figure 1B).   Conclusion: ECP quickly stabilized FEV1 decline in refractory BOS patients, compared to non-treated decliners. Randomized controlled studies are needed.