A prospective cohort study on the safety of checkpoint inhibitors in older cancer patients - the ELDERS study.

OBJECTIVE

Older cancer patients are underrepresented in the pivotal trials of checkpoint inhibitors (CPIs). This study aimed to investigate the impact of an ageing immune system on CPI-related toxicity and provide evidence for the role of geriatric assessments with CPI.

METHODS

The ELDERS study is a prospective observational study with two cohorts: older (70+ years of age) and younger (<70 years of age). Patients with advanced/metastatic non-small-cell lung cancer or melanoma starting single-agent CPI were eligible. The older cohort was assessed for frailty with Geriatric-8 (G8) screening, which when positive (<15 points) was followed by a holistic set of geriatric assessments. Primary endpoint was the incidence of grade 3-5 immune-related adverse events (irAEs).

RESULTS

One hundred and forty patients were enrolled with 43% being pretreated and pembrolizumab represented 92% of treatments on study. The older cohort had a significantly higher comorbidity burden (P < 0.001) and polypharmacy (P = 0.004). While 50% of older patients had a positive G8 screening, 60% on this frail subgroup had a performance status score of 0 or 1. There was no significant difference in the incidence of irAEs grade 3-5 between older and younger cohorts (18.6% versus 12.9%; odds ratio 1.55, confidence interval 95% 0.61-3.89; P = 0.353). Exposure to systemic steroids due to irAEs was numerically longer for older patients (22 versus 8 weeks; P = 0.208). A positive G8 screening predicted hospital admissions (P = 0.031) and risk of death (P = 0.01).

CONCLUSIONS

The use of CPI in older patients was not associated with more high-grade toxicity. The G8 screening identified a subgroup with higher risk of AEs and its implementation should be considered in the context of CPI.