In a new study, researchers have identified benefits of SARS-COV-2 mRNA vaccines for cancer patients undergoing immunotherapy. The findings, particularly relevant for melanoma patients and those with non-small cell lung carcinoma (NSCLC), suggest that these vaccines could significantly enhance the effectiveness of immune checkpoint inhibition (ICI) treatments. The study was presented at the 2024 Society for Immunotherapy of Cancer (SITC) Annual Meeting in Houston.
Personalized mRNA vaccines had previously been found to enhance responses to immune checkpoint inhibition (ICI) by stimulating IFN-α-dependent increases in PD-L1 expression in tumours. In this study, the researchers hypothesized that mRNA vaccines encoding non-tumour antigens, including those targeting SARS-COV-2, would similarly augment responses to ICI by stimulating secretion of interferon-alpha (IFN-α, a signalling protein that further enhances responses to immune checkpoint inhibitors) and PD-L1 expression (a protein crucial for immune response).
Led by Dr. Adam Grippin and Dr. Steven Lin from the University of Texas MD Anderson Cancer Center, the study found that SARS-COV-2 mRNA vaccination was associated with a marked increase in IFN-α levels in healthy volunteers. This increase correlated with higher expression of PD-L1 in tumour biopsies across various cancer types.
For melanoma patients specifically, the results were striking. Those who received a SARS-COV-2 mRNA vaccine within 100 days of starting ICI treatment showed substantially improved outcomes. Overall survival rates were significantly higher, with a 69% reduction in mortality risk compared to unvaccinated patients. Moreover, vaccinated patients exhibited better progression-free survival and a lower risk of disease progression.
This research provides crucial insights into the underlying mechanisms of how mRNA vaccines may boost immunotherapy effectiveness. The study found a significant increase in plasma IFN-α levels 24 hours after vaccination in healthy volunteers, suggesting a rapid immune response that could prime the body for enhanced cancer treatment.
While these results are promising, the researchers caution that more extensive clinical trials are needed to confirm these effects.
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