Alexandra Ladouceur1, Marina Amaral De Avila Machado2, Marie Hudson1, Cristiano Moura3 and Sasha Bernatsky3, 1McGill University, Montréal, QC, Canada, 2Research Institute of McGill University Health Center, Montréal, QC, Canada, 3Research Institute of the McGill University Health Centre, Montréal, QC, Canada
Background/Purpose: Since patients with pre-existing autoimmune conditions are commonly excluded from clinical trials with immune checkpoint inhibitors (ICI), we aimed to describe the characteristics of ''real-world" patients with pre-existing autoimmune conditions diagnosed with metastatic melanoma and started on ICI.
Methods: Using US administrative health claims data from MarketScan (Jan. 2012-July 2019), we identified a cohort of adults with metastatic melanoma (based on International Classification of Diseases, ICD physician billing or hospitalization diagnostic codes) who started ipilimumab (IPI), pembrolizumab (PEM), nivolumab (NIVO), or IPI/NIVO. Cohort entry was defined as the date of first prescription for one of these drugs. Inclusion criteria required health/drug plan coverage for 12 months before cohort entry. Pre-existing autoimmune conditions were identified, within the 12 months before cohort entry, based on ≥1 ICD physician billing or hospitalization diagnostic code for the condition of interest.
Results: We studied 3409 adults with metastatic melanoma (2071 male). Over a quarter (N=908, 26.6%) had pre-existing autoimmune conditions at baseline. Of these, the most frequent was hypothyroidism (N=380), myopathy and myositis (N=76), type I diabetes mellitus (N=44), rheumatoid arthritis (N=36) and vitiligo (N=24). Pre-existing autoimmune conditions were more frequent in women versus men (31.9% vs 23.2%). From one year to the next, there was no clear increase in the percent of pre-existing autoimmune disease among the newly diagnosed metastatic melanoma patients. There was a non-significant trend towards fewer pre-existing autoimmune conditions in patients treated with combination IPI/NIVO (22%) versus ICI monotherapy (26-28%).
Conclusion: Pre-existing autoimmune conditions are present in a considerable number of metastatic melanoma patients receiving ICI. Combination therapy with IPI/NIVO improves outcomes in metastatic melanoma, though with higher adverse events. Pre-existing autoimmune conditions might be seen by clinicians as a relative contraindication for combination ICI, but this should be evaluated in future studies.
Disclosures: A. Ladouceur, None; M. Amaral De Avila Machado, None; M. Hudson, Bristol-Myers Squibb(BMS), Boehringer-Ingelheim, Mallinckrodt; C. Moura, None; S. Bernatsky, None.
