Flu vaccine not contraindicated for checkpoint inhibitor-treated cancer patients
medwireNews: A US chart review has found no increase in the incidence of severe immune-related adverse events (irAEs) among advanced cancer patients who receive an influenza vaccination during the 2 months before or after initiating immune checkpoint inhibitor therapy.
“Based on these findings, we support the current [Advisory Committee on Immunization Practices] recommendation for annual seasonal influenza vaccination in patients on [immune checkpoint inhibitors],” the team writes in Clinical Infectious Diseases.
Researcher Mini Kamboj and colleagues from Memorial Sloan Kettering Cancer Center in New York identified 370 individuals who received an inactivated influenza vaccine at their institution within 65 days of treatment with the immunotherapy agents nivolumab, pembrolizumab, or ipilimumab, primarily for lung cancer (46%) and melanoma (19%). The study period encompassed three consecutive influenza seasons between 2014 and 2017.
Twenty percent of the participants experienced a new-onset irAE of any grade over a median follow-up of 1.4 years, with grade 3 or 4 events occurring in 8%. There were no irAEs of grade 5.
The rates were similar in a subgroup of 170 patients who initiated treatment with the PD-1 inhibitors nivolumab or pembrolizumab for the first time during the study period. Specifically, the incidence of any-grade and grade 3–4 irAEs was 18.0% and 7.6%, respectively, in this patient group. And the likelihood of developing an irAE was not significantly affected by whether individuals were vaccinated before or after initiating PD-1 blockade, the investigators report.
And they point out that these rates in the overall cohort and subgroup are “not higher than in previously published reports, which were not limited to—and likely included few—patients vaccinated for influenza during or shortly before [immune checkpoint inhibitors] treatment.”
Interestingly, laboratory-confirmed influenza occurred in 3.5% of participants across the three seasons, while the equivalent rate across the study institution was 10.7%.
Although Kamboj et al caution against drawing any definite conclusions due to the small number of events and the potential ascertainment bias due to the study design, they believe “the potential role of anti-PD-1 agents in enhancing vaccine induced protection merits further investigation in larger epidemiological studies.”
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