Immune manifestations with checkpoint inhibitors in a single Brazilian center: experience and literature review.

OBJECTIVES: The presence of autoimmune events were recorded in patients receiving immune checkpoint inhibitors. MATERIALS & METHODS: Retrospective study in patients receiving immune checkpoint inhibitors (ICIs) during the period of 2012-2019. RESULTS: A total of 554 patients received ICIs of which 123 developed an immune related adverse event. Twenty one (17%) with toxicity were identified as having a pre-existing autoimmune disease and 88 required treatment with corticosteroids or hormone replacement. Thirty two (26%) out of 123 had to temporarily discontinue ICIs due to autoimmune manifestations. Endocrine and skin manifestations were the most prevalent immune disorders in our cohort. In melanoma better efficacy was seen in patients with immune toxicity. CONCLUSION: Autoimmune diseases appear in patients receiving ICIs in this real world experience. Our results differ from other series on the frequency of autoimmunity. Complete discontinuation of ICIs due to autoimmunity was rare.

Analysis of the Abscopal Effect With Anti-PD1 Therapy in Patients With Metastatic Solid Tumors.

Abscopal effect is a rare phenomenon characterized by tumor regression of untreated metastatic lesions after a local therapy (eg, radiotherapy). We studied the probability of abscopal effect with radiotherapy associated with anti-programmed death cell 1 (PD1) therapy after progression on anti-PD1. This study is a retrospective analysis of patients treated with nivolumab or pembrolizumab for melanoma, non-small cell lung cancer (NSCLC) and renal cancer at Antônio Ermírio de Moraes Oncology Center, Brazil. To be eligible for this analysis, patients must have had unequivocal evidence of disease progression on anti-PD1 therapy and subsequent radiotherapy for any tumor site while still receiving anti-PD1. The abscopal effect was characterized as a response outside the irradiated field after radiotherapy plus anti-PD1. Sixteen patients were evaluated, including 12 metastatic melanoma, 2 metastatic NSCLC, and 2 metastatic renal cell carcinoma. The median time to disease progression on anti-PD1 was 3 months. The radiotherapy field included lung, lymph nodes, and bones, with a median total dose of 24 Gy (1-40 Gy), usually in 3 fractions (1-10 fractions). Three patients with melanoma developed an abscopal effect at a rate of 18.7% (25% among melanoma patients). Of note, one of them achieved a remarkable complete response lasting >6 months. Three patients with melanoma obtained a significant local response after radiotherapy, despite no response in distant metastases. Eleven patients presented disease progression after radiotherapy. No increased toxicity was observed. In conclusion, no patients with NSCLC or renal cancer showed abscopal effect, but 25% of patients with melanoma showed regression of nonirradiated lesions when anti-PD1 was continued after radiation to a tumor site that had progressed on anti-PD1 monotherapy.