PHOENIX-ECP- Extracorporeal Photopheresis for Immune-related Colitis and/or Hepatitis in Advanced Melanoma With Inadequate Response to Steroid Exposure

Inclusion Criteria: 1. Participants diagnosed with unresectable or metastatic melanoma ( Stage III and Stage IV) received ICI treatment (e.g., anti-PD-1, anti-PD-L1, anti-LAG-3, anti-CTLA-4 antibody, as ICI monotherapy or ICI combination therapy) and ICI paused or discontinued because of the development of ir-colitis or ir-hepatitis. 2. Participants diagnosed with ir-colitis and/or ir-hepatitis with a severity of Grade 2 or higher, based on ASCO Guidelines ( 3. Participants with endoscopic evidence of ir-colitis 4. Participants with inadequate response to corticosteroids, as defined per protocol 5. Participants who have Eastern Cooperative Oncology Group (ECOG) performance status 0, 1 or 2. Exclusion Criteria: 1. Presence of irAEs in addition to and other than ir-colitis and/or ir-hepatitis, with a higher severity grade than the irAE for inclusion (ir-colitis/ir-hepatitis) based on ASCO guidelines. 2. Participant has a diagnosis of uveal melanoma as the sole melanoma subtype 3. Treatment of ir-colitis or ir-hepatitis with any systemic therapy other than corticosteroids 4. Concurrent conditions which may require treatment with high dose corticosteroid (\> 1 milligram per kilogram per day \[mg/kg/day\]) and interfere with the corticosteroid tapering schedule recommended by the protocol. 5. Pre-existing liver disease 6. Active alcohol use disorder 7. Concomitant treatment with any chemotherapy or targeted therapy for the treatment of unresectable or metastatic melanoma. 8. Use of any investigational agent within 5 half-lives of the investigational agent prior to randomization. 9. Contraindications or known allergic reaction to any of study intervention and/or procedures 10. Participants unable to tolerate the fluid shift associated with the ECP procedure. 11. Positive result for active or previous viral infections: covid-19, hepatitis B/C, CMV, EBV, adenovirus 12. History of previous or concurrent malignancies within the last 3 years, other than unresectable or metastatic melanoma.