Itacitinib for the Treatment Steroid Refractory Immune Related Adverse Events Arising From Immune Checkpoint Inhibitors

Inclusion Criteria: * Must have signed and dated an IRB/IEC approved written informed consent form in accordance with regulatory and institutional guidelines. This must be obtained before the performance of any protocol related procedures that are not part of normal participant care. * Must be willing and able to comply with scheduled visits, treatment schedule,laboratory tests, biopsies, and other requirements of the study. * Must have received at least one immune checkpoint inhibitor (ICI) therapy either as single agent(s) or in combination(s), including but not limited to nivolumab, ipilimumab, pembrolizumab, cemiplimab, atezolizumab, durvalumab, or avelumab. * Must experience at least one Grade 2, 3 or 4 (CTCAE Version 5.0) toxicity/immune-related adverse event (irAE) attributed to immune checkpoint inhibitor (ICI) therapy as diagnosed by the patient's study physician. This may be established by clinical, histological, or imaging criteria as defined below: * Symptoms must be attributed to an immune-related adverse event (irAE), with no infectious or alternative cause suspected by the patient's study physician. * Must be actively experiencing Grade 2+ irAE (at the time of screening) as broadly defined below: * Cutaneous toxicity (including skin rash) * Colitis/enteritis (As defined by Grade 2+ diarrhea or Grade 2+ colitis (either or both conditions) * Pneumonitis * Arthritis * Hepatitis (As defined by Grade 2+ elevation in AST or ALT (either or both va…