Use of Apremilast for the Treatment of Immune Checkpoint Inhibitor Psoriasis and Psoriatic Arthritis

OBJECTIVE: The objective of this study was to present effectiveness and tolerability of apremilast in a cohort of 21 patients with immune checkpoint inhibitor psoriatic arthritis (ICI-PsA) and/or immune checkpoint inhibitor psoriasis (ICI-PsO). METHODS: This multicenter study combined data from patients treated with apremilast after experiencing ICI-PsO and/or ICI-PsA. Patients taking apremilast before ICI initiation and patients with preexisting autoimmune disease before ICI therapy were also included. Response to apremilast was determined as complete, partial, or none as determined by improvement in Common Terminology Criteria for Adverse Events grading after drug initiation. RESULTS: There were 21 patients who used apremilast for either ICI-PsO and/or ICI-PsA, but only five of these patients had de novo ICI-PsO and/or ICI-PsA. Of these five patients, four had partial response or improvement in their immune-related adverse event with apremilast, although there were intolerances in three of these patients. Of the 21 total patients, 16 had a relevant preexisting autoimmune disease, indicating a likely flare of the underlying disease with ICI therapy. Flares occurred much sooner for patients with ICI-PsA (4 weeks) compared to patients with ICI-PsO only (39.7 weeks), although the majority of both groups had grade II severity. Among the 13 patients with preexisting disease and no exposure to apremilast before ICI therapy, all patients in the ICI-PsO-only group (100%) responded to apremilast with either a complete or partial response, whereas only 57% of patients in the ICI-PsA group had complete or partial response. Twenty-nine percent of patients in the entire cohort had to discontinue apremilast due to intolerability. Thirty-eight percent of the entire cohort had progression of cancer or death at last follow-up after being on apremilast. CONCLUSION: This study highlights the potential benefit of apremilast for the treatment of ICI-PsO, both de novo and PsO flare, with less of an apparent benefit for ICI-PsA. Thirty percent of patients in the whole group had to discontinue apremilast due to intolerance. Apremilast may be an attractive therapeutic option for either condition given that it is not immunosuppressive, but further prospective observational studies with larger patient numbers are needed.