COVID-19 mRNA Vaccines Aid Immune Checkpoint Inhibitor Cancer Therapy

Many cancers elicit T cell attacks. But these cancer cells also produce “checkpoint” molecules on their surface that attach to receptors on the attacking T cells. This “handshake” between the cancer cells and the T cell quiets the T cells and allows the cancer to grow. In Nobel prize–winning research, researchers showed that immune checkpoint inhibitors (ICIs) can improve the T cell attack dramatically and can improve the patient's outcome. But ICIs don't work in some patients.

Previous studies in animals showed that SARS-CoV-2 (COVID-19) mRNA vaccines prime the attacking CD8+ T cells and augment the effect of ICI drugs. Might the same be true in humans? In an observational study of patients who received ICI therapy, investigators compared outcomes among patients who received the mRNA vaccines within 100 days of starting ICI therapy and those who didn't. The researchers adjusted for multiple potential confounders.

In 1000 patients with unresectable stage III or stage IV non–small-cell lung cancer and in 200 patients with stage IV melanoma, median and 3-year overall survival were significantly better in those who had received mRNA vaccines near the start of ICI therapy. In both animal and preclinical human studies, the researchers showed that the mRNA vaccines augmented the immune response by increasing production of type I interferon, which activated myeloid cells and lymphocytes.