Background:
Immune checkpoint inhibitors have changed the landscape of medical oncology, with sustained tumour responses in traditionally aggressive cancers. Immune-related adverse events (IRAEs) are a known complication that can result in significant morbidity, but are predictive of response in advanced melanoma(1). Early time to response may also potentially guide physicians towards shorter treatment courses, leading to improved health economic resource utilisation. We sought to investigate the hypothesis of IRAE being predictive of response to immunotherapy in advanced melanoma and lung cancer, amongst early responders.
Methods:
A retrospective audit at a tertiary centre (Austin Hospital) was conducted assessing all patients receiving immunotherapy with either ipilimumab, pembrolizumab, nivolumab or in combination between January 2005 to March 2017. Those patients receiving 5 or less cycles of nivolumab or pembrolizumab or 3 or less cycles of ipilimumab (including combination immunotherapy) were included for analysis. Data extracted included IRAE graded by CTCAE V4.03, sites of disease, time to response, tumour and patient characteristics.
Results:
One hundred and twenty patients were identified. Of these, 19 (7 melanoma and 12 lung cancer) had early IRAE resulting immunotherapy cessation. Of the 7 melanoma patients, 5 had partial response (PR), 1 complete response and 1 stable disease on first radiological assessment by RECIST criteria. Of the 12 lung cancer patients (all receiving nivolumab), only 1 patient had PR. The remaining 11 (91.6%) patients’ best response was disease progression. Grade 3 or 4 IRAEs included hepatitis (6), pneumonitis (4), colitis (3) arthritis (1), cerebritis (1) and nephritis (1).
Conclusion:
Our data supports existing literature that IRAE from immune checkpoint inhibitors are predictive of response in melanoma. However, we did not find the same association in advanced lung cancer. Further research is needed in this area across tumour subtypes other than melanoma.