Immune-Related Adverse Events After Immune Checkpoint Inhibitors for Melanoma Among Older Adults

Abstract

Importance: Immune checkpoint inhibitors (ICIs) have improved survival in patients with advanced melanoma but can be associated with a spectrum of immune-related adverse events (AEs), including both autoimmune-related AEs and other immune-related inflammatory AEs. These associations have primarily been evaluated in clinical trials that include highly selected patients, with older adults often underrepresented.

Objective: To evaluate the association between use of ICIs and immune-related AEs (autoimmune and other immune related) among older patients with cutaneous melanoma.

Design, setting, and participants: A population-based cohort study was conducted from January 1, 2011, to December 31, 2015. Data were analyzed from January 31 to May 31, 2021. With use of a linked database of Medicare claims and Surveillance, Epidemiology, and End Results (SEER) Program population-based cancer registries, patients of White race diagnosed with stages II-IV or unknown (American Joint Committee on Cancer, AJCC Cancer Staging Manual 6th edition) first primary cutaneous melanoma during 2011-2015, as reported to SEER, and followed up through December 31, 2015, were identified.

Exposures: Immune checkpoint inhibitors for treatment of melanoma.

Main outcomes and measures: The association between ICIs and immune-related AEs ascertained from Medicare claims data was estimated using multivariable Cox regression with hazard ratios (HRs) and 95% CIs and with cumulative incidence accounting for competing risk of death.

Results: The study included 4489 patients of White race with first primary melanoma (3002 men [66.9%]; median age, 74.9 [range, 66.0-84.9] years). During follow-up (median, 1.4 [range, 0-5.0] years), 1576 patients (35.1%) had an immune-related AE on a Medicare claim. Use of ICIs (reported for 418 patients) was associated with autoimmune-related AEs (HR, 2.5; 95% CI, 1.6-4.0), including primary adrenal insufficiency (HR, 9.9; 95% CI, 4.5-21.5) and ulcerative colitis (HR, 8.6; 95% CI, 2.8-26.3). Immune checkpoint inhibitors also were associated with other immune-related AEs (HR, 2.2; 95% CI, 1.7-2.8), including Cushing syndrome (HR, 11.8; 95% CI, 1.4-97.2), hyperthyroidism (HR, 6.3; 95% CI, 2.0-19.5), hypothyroidism (HR, 3.8; 95% CI, 2.4-6.1), hypopituitarism (HR, 19.8; 95% CI, 5.4-72.9), other pituitary gland disorders (HR, 6.0; 95% CI, 1.2-30.2), diarrhea (HR, 3.5; 95% CI, 2.5-4.9), and sepsis or septicemia (HR, 2.2; 95% CI, 1.4-3.3). Most associations were pronounced within 6 months following the first ICI claim and comparable with or without a baseline history of autoimmune disease. The cumulative incidence at 6 months following the first ICI claim was 13.7% (95% CI, 9.7%-18.3%) for autoimmune-related AEs and 46.8% (95% CI, 40.7%-52.7%) for other immune-related AEs.

Conclusions and relevance: In this cohort study of older adults with melanoma, ICIs were associated with autoimmune-related AEs and other immune-related AEs. Although some findings were consistent with clinical trials of ICIs, others warrant further investigation. As ICI use continues to expand rapidly, ongoing investigation of the spectrum of immune-related AEs may optimize management of disease in patients.

Figure.. Cumulative Incidence of Selected Autoimmune- and Other Immune-Related Adverse Events (AEs) Among Patients Diagnosed With Cutaneous Melanoma, Accounting for Competing Risk of Death, by Receipt of Immune Checkpoint Inhibitors (ICIs)

eTable 2 in the Supplement provides the definition of autoimmune-related AEs (A-C) and other immune-related AEs (D-H). Cumulative incidence in the absence of ICIs is provided for perspective, but the curves have different time scales and are not adjusted for differences between the populations and should therefore be interpreted cautiously. eTable 4 in the Supplement provides point estimates and 95% confidence bounds. Individuals with a previous claim (at or before melanoma diagnosis) were excluded from analyses of autoimmune-related AEs (overall), primary adrenal insufficiency, ulcerative colitis, hypothyroidism, and hypopituitarism as described in eTable 2 in the Supplement. For all outcomes, the number at risk at the start of an interval excludes people who had the event earlier in follow-up, died, or ended follow-up before the start of the interval. ^aSmall numbers were suppressed for privacy.