EPIC- Extracorporeal Photopheresis (ECP) for Immune-related Colitis

Inclusion Criteria: * Participants diagnosed with unresectable or metastatic melanoma or unresectable, advanced or metastatic NSCLC, who received ICI treatment with agents like anti-programmed death-1 (PD-1), anti-cytotoxic T-lymphocyte antigen 4 (CTLA-4), and had shown a response to the treatment, based on having a complete response, partial response, or stable disease determined by Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 criteria. * Participants diagnosed with ir-colitis of at least Grade 2 severity based on American Society of Clinical Oncology (ASCO) Guidelines (diarrhea with an increase of ≥4 stools more than at baseline) with other causes of diarrhea and colitis ruled out. * Participants with endoscopy evidence of ir-colitis based on colonoscopy (modified Mayo Endoscopy Subscore of ≥2). * Participants with inadequate response to corticosteroids, defined as no improvement in ir-colitis after at least 72 hours of corticosteroid treatment, or relapse of ir-colitis during or after corticosteroid tapering. * Participants who have an Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 2. * Participants who may become pregnant must have a negative serum pregnancy test, agree to use effective birth control methods during the study and for 30 days after the last treatment, and not be breastfeeding. * Participants whose sexual partner may become pregnant, must use condoms or other effective contraception, and avoid donating blood, semen, or spe…