POS0432 USE OF APREMILAST FOR THE TREATMENT OF IMMUNE CHECKPOINT INHIBITOR-INDUCED PSORIASIS AND PSORIATIC ARTHRITIS

Background: Apremilast is a phosphodiesterase-4 inhibitor that is approved for the treatment of psoriasis (PsO), psoriatic arthritis (PsA), and oral ulcers from Behcet's disease. Despite its non-immunosuppressive nature, its use for the treatment of immune-related adverse events (irAE) from immune checkpoint inhibitors (ICI), specifically ICI-induced PsO (ICI-PsO) and ICI-induced PsA (ICI-PsA) has not been widely reported. A recent systematic literature review identified only 18 individual cases of patients with ICI-PsO/PsA that were treated with apremilast [1]. Objectives: To describe the use of apremilast in a cohort of patients with ICI-PsO and ICI-PsA to explore effectiveness and tolerability. Methods: This was a retrospective observational study including all patients that were treated with apremilast for any irAE indication, including those that had pre-existing autoimmune disease, from three different major U.S. academic medical centers. The study was approved by the HSS internal review board, the individual institutions and data transfer agreements were set in place. Variables gathered included demographics, cancer type and stage, ICI regimen, irAE time of onset, severity per Common Terminology Criteria for Adverse Events, and response and tolerability to apremilast for irAE treatment. Response to apremilast was determined as complete, partial, or none by medical record review. Descriptive statistics were used to describe variables. Results: We identified 23 patients that used apremilast for an irAE indication, 21 used it for either ICI-PsO and/or ICI-PsA (Table 1), and two used it for oral ulcers or lichen planus. Of the 21 ICI-PsO/PsA patients, ten used it for PsO alone and eleven used it for PsA, with (8/11) or without (3/11) PsO. Mean age was 59 years (SD 12), 71% were male, and 90% of the cohort was white. Melanoma, lung, and genitourinary cancers were most prevalent, and about half the patients were being treated for stage 4 cancer. Sixty-two percent of this cohort used anti-PD1/PDL-1 monotherapy and the rest used combination therapy (anti-PD1/L1 and anti-CTLA-4). Age, sex, race, stage and ICI regimen was similar for the only PsO group and the PsA group. Seventy-six percent of patients had a pre-existing autoimmune disease such as PsO, PsA or inflammatory bowel disease. One patient was on apremilast for PsO+PsA at baseline before ICI initiation, and another patient was remotely on apremilast five years prior to ICI initiation for PsO+PsA. Median onset of irAE for the group as a whole was 18 weeks from ICI initiation, but it was 34.4 weeks for the PsO group and 6.3 weeks for the PsA group. Most of the patients experienced grade II irAE. All in the only PsO group (100%) responded to apremilast as either complete or partial response, whereas only 54% of patients in the PsA group had complete or partial response. Four patients required the use of steroids for their irAE (2 in each group), but only the PsO patients were able to discontinue their steroids at the time of last follow-up. Three patients in the PsA group used DMARD therapy at some point – 2 used methotrexate and one used sulfasalazine. About 30% of patients in the entire cohort had to discontinue apremilast due to intolerability, such as diarrhea (4 patients), nausea (2 patients) and depression (1 patient). Cancer status at last follow-up was similar for the two groups with about 1/3 of the cohort having progression of disease or death at time of last follow-up. Apremilast was not effective for the two patients with oral ulcers and lichen planus, and it was discontinued for inefficacy. Conclusion: This is the largest published cohort of patients who were treated with apremilast for an irAE, primarily PsO and PsA. Apremilast for ICI-PsO allowed for limited oral steroid use compared to ICI-PsA, and tolerability in this cohort was similar to previous studies of apremilast in non-ICI settings. This study highlights the potential favorable use of apremilast for the treatment of ICI-PsO over ICI-PsA though further studies with larger patient numbers are still needed, especially to assess effects on cancer response. REFERENCES: [1] Kaur, Manjit, et al. "Apremilast for immune checkpoint inhibitor-associated psoriasis and psoriatic arthritis: A systematic review." JAAD Reviews 2 (2024): 149-152. Acknowledgements: NIL . Disclosure of Interests: Nilasha Ghosh: None declared, Pankti Reid Conducted unbranded speaking for Amgen, advisory board participation for AbbVie, PADCEV, Jeffrey A. Sparks Dr. Sparks has received research support from Boehringer Ingelheim, Bristol Myers Squibb, Johnson & Johnson, and Sonoma Biotherapeutics unrelated to this work. He has performed consultancy for AbbVie, Amgen, Boehringer Ingelheim, Bristol Myers Squibb, Fresenius Kabi, Gilead, Inova Diagnostics, Johnson & Johnson, Merck, MustangBio, Novartis, Optum, Pfizer, ReCor, Sana, Sobi, and UCB unrelated to this work, Kaitlin McCarter: None declared, Kyle Ge: None declared, Anne Bass: None declared. © The Authors 2025. This abstract is an open access article published in Annals of Rheumatic Diseases under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Neither EULAR nor the publisher make any representation as to the accuracy of the content. The authors are solely responsible for the content in their abstract including accuracy of the facts, statements, results, conclusion, citing resources etc.