Introduction
Immunotherapy (IO) is a well-established cancer therapy, however, a subset of patients experience severe immune related adverse events (irAEs) necessitating hospitalisation and resulting in treatment discontinuation. We examined the safety of rechallenging this cohort of patients.
Methods
A comprehensive, retrospective, single centre analysis was conducted, examining medical records of cancer patients who received immune checkpoint inhibitors at St John of God Subiaco Hospital between 2016 and 2018. Data from patients who required hospitalisation was recorded from 2016 to 2022. Patients’ cancers, immunotherapies, toxicities, hospital management and outcomes were analysed.
Results
Of the 307 patients that received IO over two years, 22% (n=69) had irAEs requiring hospital admission. Of those 69 patients, 68% (n=47) were rechallenged with immunotherapy. The median duration between toxicity and rechallenge was 49 days, the shortest duration was 17 days and the longest was 994 days. 40% (n=19) were readmitted with irAEs. The median toxicity grade of those readmitted was 3, two of these patients required ICU admission, 1 died as a result of their toxicity. 40% (n= 19) of the 47 patients that were rechallenged were alive at the end of 2022. Of the 19 patients that were still alive, 95% (n=18) had a diagnosis of metastatic melanoma. Of the 18 metastatic melanoma patients, 100% had a complete metabolic response (CMR) at the end of 2022, one of whom ceased IO due to toxicity but then proceeded to have a CMR.
Conclusion
The decision to rechallenge patients subsequent to hospitalisation for irAEs is nuanced. Our review found that rechallenging can be safely performed, however it underscores the value of a tailored approach in a carefully selected subset of patients.