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.