The mRNA COVID-19 vaccination seems to offer an unexpected advantage: it may extend the lives of cancer patients by enhancing immunotherapy effectiveness.

A study analyzing about 1,000 individuals undergoing treatment for advanced skin and lung cancer revealed that those who received an mRNA COVID-19 vaccine within 100 days of starting treatment with an immune checkpoint inhibitor had nearly double the survival time compared to those who did not receive the vaccine during this period. Clinical trials to validate these findings are set to commence by year-end.

“The outcomes were astonishing,” states Elias Sayur, a researcher at the University of Florida. They speculate about the potential to develop an mRNA vaccine that enhances this immune response. “Could we craft a universal mRNA vaccine that activates the immune system across all cancer patients?” he muses. “The possibilities are extensive.”

However, is it advisable for someone just commencing checkpoint inhibitors to get a COVID-19 vaccine to improve treatment efficacy? “I am hesitant to provide clinical recommendations without concrete proof,” Sayur cautions. “Attempting to harness your immune system against cancer also carries risks,” he adds, urging adherence to established vaccine guidelines.

The rationale behind this finding lies in the immune system’s capacity to eliminate many cancers even before they escalate. Yet, some tumors evolve to obstruct this response. They achieve this by manipulating the “off switch” of T cells, which are responsible for destroying cancer cells. A well-known off switch is the protein PD-1 found on T cell surfaces.

PD-1 becomes inactive when it binds to a protein called PD-L1 on certain cell surfaces. This serves as a safety mechanism for cells to signal, “cease the attack, I am benign.”

Numerous cancers hijack PD-L1 by producing it in excessive amounts. Checkpoint inhibitors function by preventing PD-1 and other off switches from becoming activated. These treatments have significantly increased survival rates for conditions like lung cancer and melanoma, earning a Nobel Prize for their developers in 2018.

However, the efficacy of checkpoint inhibitors varies significantly. When an individual’s immune system fails to react to the tumor by dispatching T cells for an attack, these drugs offer limited benefit.

Consequently, combining checkpoint inhibitors with vaccines that bolster the immune system’s tumor combat capabilities could prove to be more effective than either strategy used in isolation. Cancer vaccines are generally tailored to elicit a response to mutated proteins in cancer cells and are often personalized. “We are attempting to discern the unique aspects of their tumors,” Sayur explains. “It demands substantial time, funding, and complexity.”

During cancer vaccine trials, his team observed that the non-specific mRNA vaccine used as a control also exhibited remarkable effectiveness. “It was an absolute surprise,” Sayur remarks.

In July, Sayur and colleagues published findings indicating that mRNA vaccines enhance anti-tumor responses, even when not aimed at cancer-specific proteins, as revealed in studies in mice. Vaccines can initiate an innate immune response that acts like an alarm, energizing the immune system and prompting T cells to move from tumors to lymph nodes, where they rally other immune cells for a focused attack.

Recognizing this potential, Sayur and his team examined the medical records of patients treated at the University of Texas MD Anderson Cancer Center.

Out of 884 advanced lung cancer patients receiving checkpoint inhibitors, 180 had received mRNA COVID-19 vaccinations within 100 days of initiating treatment. Those vaccinated survived for approximately 37 months, contrasting with roughly 20 months for those unvaccinated.

Furthermore, among 210 individuals with melanoma that had metastasized, 43 had been vaccinated within 100 days of starting checkpoint inhibitors. They had a survival time of around 30 to 40 months, compared to around 27 months for individuals who were not vaccinated in that time frame. Some vaccinated individuals remained alive at the time of analysis, indicating their survival may extend even longer. The research findings were shared at the European Society of Medical Oncology Congress in Berlin, Germany.

Previous reports have suggested that after receiving an mRNA COVID-19 vaccine, a proportion of tumors exhibited shrinkage, indicating potential anti-tumor effects in certain cases even without checkpoint inhibitors. “It’s certainly a possibility, but further investigations are essential to fully understand,” comments Sayur.

The United States recently declared significant cuts in funding for mRNA vaccine development, despite the substantial benefits they have provided during the pandemic and the vast potential they hold for treatments beyond vaccines.