Drug monitoring of orally administered 8-methoxypsoralen in patients treated with extracorporeal photopheresis

Recently extracorporeal photopheresis (ECP). a new therapy involving extrac orporeal activation of orally administered 8-methoxypsoralen (8-MOP), has b een established for the treatment of different skin diseases. The pharmacok inetic profile of 8-MOP has been pursued in a clinical study which aimed to assess the efficacy of ECP in patients with progressive systemic sclerosis and cutaneous T-cell lymphoma, However, the enormous intraindividual varia tions in plasma as well as buffy coat concentrations affect the efficacy of oral 8-MOP therapy. Therefore, the introduction of a liquid 8-MOP formulat ion enabling the direct administration of the drug into the treatment bag o f the ECP device is challenging.