Cancer outcomes in patients requiring immunosuppression in addition to corticosteroids for immune-related adverse events after immune checkpoint inhibitor therapy

Aim To examine the cancer-specific outcomes for patients who experience immune-related adverse events requiring immunosuppression beyond corticosteroids. Methods We performed a retrospective case series of patients between January 1, 2009 and April 1, 2018, across three metropolitan hospitals in Adelaide, South Australia. Eligible patients were identified from pharmacy records. Patients with a solid organ malignancy had discontinued checkpoint inhibitor therapy due to toxicity, and required immunosuppression in addition to corticosteroids to treat any immune-related adverse event. Results From 3860 patient dispensation records of immunosuppressive medications, 19 eligible patients were identified. Eight received a CTLA-4 inhibitor, four a PD-1 inhibitor, five combination immunotherapy, and two remained blinded. Sixteen patients had melanoma and three had non-small cell lung cancer. Median time to treatment failure was 8.7 months, and median overall survival was 9.4 months. Of those evaluable, the objective response rate was 35%, while 53% had progressive disease. Four patients died due to complications of their irAE, while six died from progressive disease. Conclusion Patients who received immunosuppression for checkpoint inhibitor therapy toxicity had variable outcomes. This in part reflects a heterogeneous population, and the evolution of irAE management over time. Several patients continued to derive a benefit after cessation of therapy despite the use of immunosuppressive medications; conversely, four died as a direct consequence of their irAE. Physicians should promptly introduce immunosuppressive therapy in patients not responding to corticosteroids to mitigate the risk of life-threatening adverse events, given that current evidence does not clearly demonstrate a detriment to cancer-specific outcomes.