Comparison of two inline photopheresis systems: A paired crossover trial.

Background: Extracorporeal photopheresis (ECP) has been demonstrated as an effective treatment for graft-versus-host disease (GvHD). The inline system was developed by Therakos in 1987. Recently, Fresenius Kabi implemented an integration of cell separator Amicus and a UVA photoactivation device (Phelix), realizing an inline photopheresis system.

Study design and methods: In 2022 we designed a prospective paired crossover trial (NCT05718674) comparing two integrated ECP protocols: Therakos CELLEX and Amicus ECP system. Twenty patients affected by corticosteroid resistant GvHD were submitted to 80 ECP, 40 paired procedures.

Results: All procedures were well tolerated, with no significant differences in procedure duration. CELLEX cell product showed higher granulocytes and platelet content, while Amicus cell product exhibited higher enrichment of lymphocytes, resulting in significantly higher MNC purity (92.9% vs. 84%). A significantly higher granulocytes and platelets absolute content was observed in CELLEX cell products, while Amicus cell products showed a significantly higher number of TNCs and MNCs. Differences in granulocyte and platelet content remained significant even after normalization of the data according to blood volume processed. These findings are confirmed by a statistically significant higher CE2% for CELLEX for granulocytes and platelets along with the lack of significant difference observed for TNCs and MNCs.

Discussion: Our analysis shows differences in the characteristics of the procedure and the cell product. Anyway, both devices are effective for performing ECP procedure, as they collect a cell product suitable for photopheresis. At present, our results represent the first data set comparing two available inline ECP devices.