Immune-mediated adverse events following influenza vaccine in cancer patients receiving immune checkpoint inhibitors.

Objectives: The emergence of immune checkpoint inhibitors has transformed treatment paradigms for various malignancies. Patients with cancer are at increased risk of complications and hospitalizations from influenza; therefore, it is recommended that they receive inactivated influenza vaccination. However, efficacy and safety of inactivated influenza vaccination in patients receiving immune checkpoint inhibitors is uncertain. The objective of this prospective case series was to evaluate the incidence of immune-mediated adverse events (imAEs) following inactivated influenza vaccination in patients receiving immune checkpoint inhibitors. Changes in cytokine and chemokine levels were also evaluated.
Methods: Patients receiving immune checkpoint inhibitors during the 2017-2018 influenza season were eligible for study participation. Peripheral blood samples were collected prior to administration of inactivated influenza vaccine and two post-vaccination time points. Evaluation of new or worsening imAEs occurred via patient questionnaire and review of medical records for 60 days following inactivated influenza vaccination. Baseline imAEs were evaluated from review of medical records for 60 days prior to inactivated influenza vaccination. Serum cytokines and chemokines were measured using a multiplex Luminex assay.
Results: Twenty-four patients were enrolled in this study. Seven patients experienced any grade imAE (one patient having 2) within 60 days following inactivated influenza vaccination. The majority were Grades 1-2, including rash ( n  = 3), hypothyroidism, myalgia, and colitis ( n  = 1 each). Two patients experienced severe imAEs (grade 3 nephritis and grade 4 diabetes). No significant changes ( p  > 0.05) in serum cytokine or chemokine concentrations were observed.
Conclusions: Although small, our study suggests that inactivated influenza vaccine may be safely administered to patients receiving immune checkpoint inhibitors. The majority of imAEs following inactivated influenza vaccination were Grades 1-2 and did not require changes in immune checkpoint inhibitor therapy.