Oral Presentation Clinical Oncology Society of Australia Annual Scientific Meeting 2024

Estimating rates of immune-related adverse events in an Australian state-wide hospital population (#112)

Bishma Jayathilaka 1 2 3 , Fan He 2 , Maarten IJzerman 2 3 4 , George Au-Yeung 3 5 , Fanny Franchini 2
  1. Pharmacy Department, Peter MacCallum Cancer Centre, Parkville, VICTORIA, Australia
  2. Cancer Health Services Research, Centre for Cancer Research, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Melbourne, Victoria, Australia
  3. Sir Peter MacCallum Department of Oncology, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Melbourne, Victoria, Australia
  4. Erasmus School of Health Policy & Management, Erasmus University, Rotterdam, The Netherlands
  5. Department of Medical Oncology, Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia

Background 

Immune-related adverse events (irAE) complicate the use of immune checkpoint inhibitors (ICI). There are limited real-world studies examining potential contributors to identify patients at risk. We aimed to estimate rates of irAE among patients in hospital admitted and emergency episodes across Victoria, Australia using linked administrative datasets. 

 

Method

We analysed episodes of care coded by International Statistical Classification of Diseases and Related Health Problems 10th Revision Australian Modification (ICD-10-AM) to infer irAE-related admissions/visits. We used the PRedicting the population health economic IMpact of current and new CAncer Treatments dataset containing patients in Victorian Cancer Registry diagnosed with specific cancers between 2010-2021. Patients were linked to Commonwealth datasets (Pharmaceutical Benefits Scheme [PBS], Medicare Benefits Scheme, National Death Index). We identified patients who received at least one ICI dose (ipilimumab, nivolumab, pembrolizumab, durvalumab, avelumab, atezolizumab, cemiplimab). We developed definitions for irAE occurrence based on ICD-10-AM codes. We applied definitions to the Victorian Admitted Episodes Dataset (VAED) and Victorian Emergency Minimum Dataset (VEMD) to estimate irAE occurrence rates among ICI exposed patients. 

 

Results

Among 213,476 patients, 7,175 received at least one ICI dose. Colitis/enterocolitis was the most identified irAE inferred in VAED and VEMD. Combined rate for all colitis/enterocolitis definitions was 21.26%. Rarer irAE types were inferred from VAED including neurological and cardiac. Inference rate of neuropathy was 1.20%. Inference rates for myocarditis and pericarditis were 0.84% and 0.70%, respectively. 

 

Conclusion

Our findings are comparable to observational/cohort studies suggesting our method to infer irAE at a population-level may be appropriate but requires validation in different datasets. Identifying irAE occurrence is a crucial step towards evaluating factors associated with irAE risk, which is the next stage of research. Our project contributes to the growing knowledge on real-world irAE prevalence and underscores the potential use of administrative data to examine irAE risk factors.