Extracorporeal Photopheresis with 5-Aminolevulinic Acid in Crohn’s Disease—A First-in-Human Phase I/II Study

<b>Background/Objectives:</b> With the increasing prevalence of Crohn's disease (CD), treatment options for patients who fail conventional and advanced therapy are highly needed. Therefore, we explored the safety and efficacy of extracorporeal photopheresis (ECP) using 5-aminolevulinic acid (ALA) and blue light (405 nm). <b>Methods:</b> Patients with active CD who failed or were intolerant to biological therapy were eligible. Mononuclear cells (90 mL) were collected from each patient using a Spectra Optia^® apheresis system and diluted with 100 mL of 0.9% sodium chloride in a collection bag. The cells were incubated with ALA at a concentration of 3 millimolar (mM) for 60 min ex vivo and illumination with an LED blue light (405 nm) source (BLUE-PIT^®) before reinfusion to the patient. Recording of vital signs and adverse events were regularly performed. At week 13, we assessed the patients with colonoscopy, the Harvey Bradshaw Index (HBI), the Inflammatory Bowel disease Health Related Quality of Life Questionnaire, and the measurement of serum C-reactive protein and fecal calprotectin (FC) levels. Biopsies of the intestines were taken for immunohistochemistry. <b>Results:</b> Seven patients were included. Four patients completed the treatments, with a total of 24 treatments. Three of the four patients achieved a favorable response, including a lower HBI, lower FC levels, and/or endoscopic improvement. No significant adverse events were observed. The remaining three patients received only one, three, or five treatments due to technical difficulties, medical reasons, or the withdrawal of informed consent. <b>Conclusions:</b> ALA-based ECP appears safe and seems to give some clinical improvement for the patients with active CD who failed to respond to conventional and advanced therapies.