The efficacy and toxicity of immune checkpoint inhibitors in a real-world older patient population

Immunotherapy has emerged as an effective treatment option for the management of advanced cancers. The effects of these immune checkpoint inhibitors in the older patient population has not been adequately assessed.

To understand the impact of aging on CTLA-4 and PDL-1 inhibitors efficacy and immune-related adverse events (irAE) in the context of real-world management of advanced solid cancers.

This retrospective study involved all non-study patients with histologically-confirmed metastatic or inoperable solid cancers receiving immunotherapy at Kingston Health Sciences Centre. We defined 'older patient' as age ≥ 75. All statistical analyses were conducted under SPSS IBM for Windows version 24.0.

Study outcomes included immunotherapy treatment response, survival, as well as number, type, and severity of irAEs.

Our study (N = 78) had 29 (37%) patients age <65, 26 (33%) patients age 65-74, and 23 (30%) patients age ≥75. Melanoma, non-small cell lung cancer, and renal cell carcinoma accounted for 70%, 22%, and 8% of the study population, respectively. Distributions of ipilimumab (32%), nivolumab (33%), and pembrolizumab (35%) were similar in the study. The response rates were 28%, 27%, and 39% in the age <65, age 64-74, age ≥75 groups, respectively (P = 0.585). Kaplan-Meier curve showed a median survival of 28 months (12.28-43.9, 95% CI) and 17 months (0-36.9, 95% CI) in the age <65 and age 64-74 groups, respectively; the estimated survival probability did not reach 50% in the age ≥75 group (P = 0.319). There were no statistically significant differences found in terms of irAEs, multiple irAEs, severity of grade 3 or higher, types of irAEs, and irAEs resolution status when comparing between different age groups.

Our results suggest that patients age ≥75 are able to gain as much benefit from immunotherapy as younger patients, without excess toxicity. Our findings suggest that single agent immunotherapy is generally well-tolerated across different age groups with no significant difference in the type, frequency or severity of irAEs. Future studies evaluating aging and combination immunotherapy are warranted.

Journal of geriatric oncology. 2018 Aug 10 [Epub ahead of print]

Joobin Sattar, Adi Kartolo, Wilma M Hopman, Joshua Matthew Lakoff, Tara Baetz

Department of Medicine, Queen's University, Kingston, Ontario, Canada., Kingston General Health Research Institute, and Department of Public Health Sciences, Kingston, Ontario, Canada., Department of Medicine, Queen's University, Kingston, Ontario, Canada; Department of Endocrinology, Kingston, Ontario, Canada., Department of Medicine, Queen's University, Kingston, Ontario, Canada; Kingston General Health Research Institute, and Department of Public Health Sciences, Kingston, Ontario, Canada; Cancer Centre of Southeastern Ontario, Kingston, Ontario, Canada. Electronic address: .