Immune-related adverse events predict the therapeutic efficacy of anti-PD-1 antibodies in cancer patients

Abstract

Background: Cancer immune therapy has shown remarkable benefit in the treatment of a range of cancer types, although it may initiate autoimmune-related disorders in some patients. We have attempted to establish whether the incidence of irAEs after the use of anti-PD-1 antibodies nivolumab or pembrolizumab in advanced malignancies is associated with anti-PD-1 treatment efficacy.

Patients and methods: We studied patients treated with single-agent nivolumab or pembrolizumab for advanced cancer. irAEs (immune-related adverse events) were identified clinically and graded as per the Common Terminology Criteria for Adverse Events version 4.0. Efficacy was evaluated with objective response rate (ORR, immune-Response Evaluation Criteria in Solid Tumours [RECIST] criteria) progression-free survival (PFS) and overall survival (OS). Tests were performed to determine the association between irAEs and ORR, PFS or OS.

Results: We identified 106 patients. Primary diagnoses were lung cancer (n = 77), melanoma (n = 8), head and neck carcinoma (n = 7), renal carcinoma (n = 5), Hodgkin's lymphoma (n = 3), urothelial carcinoma (n = 3) and gallbladder adenocarcinoma, hepatocellular carcinoma and Merkel cell carcinoma (n = 1 each). IrAEs were observed in 40 patients (37.7%). The most frequent irAEs were hypothyroidism (n = 15), nephritis (n = 5) and hyperthyroidism (n = 4). Objective response was observed in 44 patients (41.5%), and median PFS was 5.5 months (0.5-31 months). Thirty-three of the 40 patients with irAEs had objective response (82.5%) in contrast with 11 of the 66 cases without irAEs (16.6%) (OR 23.5, P < 0.000001). PFS in patients with irAEs was 10 months and 3 months in those without irAEs (HR 2.2, P = 0.016). OS in patients with irAEs was 32 months and 22 in those without irAEs, without statistically significant differences.

Conclusion: In advanced cancer treated with single-agent anti-PD-1 antibodies, patients with irAEs showed a markedly improved efficacy over patients without irAEs (ORR of 82.5% and PFS of 10 months vs ORR of 16.6% and PFS of 3 months). Future studies of anti-PD-1 immune-therapy should address this association to explore the underlying biological mechanisms of efficacy.

Keywords: Advanced cancer; Immune-related adverse events; Nivolumab; Pembrolizumab; Response predictive factor.