Evaluation of the use of COVID-19 vaccines in patients treated with immunotherapy.

Abstract

e18781 Background: Immunotherapy can boost a patient’s immune system to bring about anti-tumor activity and may theoretically exaggerate the inflammatory immune response to infection or vaccinations. Conversely, vaccination may enhance immune activity in patients on immunotherapy. Currently, there are limited safety data in patients treated with immunotherapy who received COVID-19 vaccines. Methods: An IRB-approved retrospective review of Dana-Farber Cancer Institute patients treated with PD-1 checkpoint inhibitors and received COVID-19 vaccines was performed. The primary endpoint was the incidence rate of immune-related adverse events (irAEs) pre- and post- COVID-19 vaccinations. An Electronic Health Record search identified all patients who completed COVID-19 vaccines between 12/1/2020 and 3/31/2021 and received anti-PD-1 monotherapy between 10/1/2020 and 5/31/2021. Medical record review identified timing, occurrence, and grading of irAEs as defined by clinicians or Common Terminology Criteria for Adverse Events (CTCAE), version 5.0. Results: A total of 229 patients were included in the study. The most common underlying cancers were lung (32%) and melanoma (26%). The majority of patients had Pfizer-BioNTech COVID-19 vaccine; 64% of all patients received the third dose of vaccine. The median duration of treatment was 15 months, and median duration of follow-up was 19 months. Among the study cohort, 120 irAEs occurred before vaccination (any grade); 30 (25%) were grade 1, 35 (29%) were grade 2, 11 (9%) were grade 3 or 4, and 44 (37%) were ungraded. The main types of irAEs were skin toxicities (37% of all irAEs) followed by thyroid dysfunction (22%) and colitis (11%). Of the 75 irAEs that occurred after vaccination, 24 (32%) were grade 1, 16 (21%) were grade 2, 16 (21%) were grade 3 or 4, and 19 (26%) were ungraded. The main irAEs types were skin toxicity (31% of all irAEs) followed by thyroid dysfunction (13%) and hepatic toxicity (12 %). The all-grade pre- and post-vaccine irAE incidence rates per 100 patient-months were 4.13 and 5.09, respectively. Within this cohort, there were 0.96 (95% CI -0.362-2.284, p = 0.15) more irAEs post vaccine per 100 patient-months of anti-PD-1 therapy. Conclusions: The data weakly suggested that there is a higher incidence of irAEs post COVID-19 vaccine; however, the comparison did not achieve statistical significance. Further analysis of other patient characteristics will help to determine if any specific patterns are observed.[Table: see text]