Researchers developed a system that redirects pre-existing antiviral signals to help the immune system recognize and attack cancer cells.
RT’s Three Key Takeaways:
- Harnessing Antiviral Memory: The PROTEXI platform redirects immune responses generated by SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) infection or vaccination to act as a catalyst for antitumor immunity.
- Improved Survival Rates: Preclinical studies in melanoma and breast cancer models showed the vaccine reduced tumor burden, enhanced the effectiveness of other immunotherapies, and created long-lasting immune memory.
- Upcoming Clinical Trials: Researchers plan to initiate first-in-human clinical evaluations of the personalized vaccine in patients with sarcoma, a disease that often evades traditional treatments.
Scientists from Celloram Inc, University Hospitals, and Case Western Reserve University developed a cancer vaccine platform that repurposes immune memory from COVID-19 to target tumors, according to a study published in Nature Communications.
The platform, known as PROTEXI, is a dendritic cell vaccine designed to use pre-existing antiviral immune memory to improve the body’s ability to identify and eliminate cancer. While cancer vaccines have historically struggled to generate strong immune responses in “immune-cold” tumors, this approach uses the mass immune memory created by the global pandemic to stimulate a response.
“Rather than inventing a completely new immune response, we are enhancing the ability of the immune system to recognize cancer by leveraging anti-viral memories it already has,” said Tej Pareek, chief executive officer of Celloram Inc.
The platform works by pairing tumor-specific antigens with helper signals from SARS-CoV-2 Spike protein epitopes. These epitopes are small fragments recognized by immune systems already primed through previous infection or vaccination. This pairing converts dormant antiviral memory into an active response against cancer cells.
In preclinical models of melanoma and breast cancer, the vaccine slowed tumor growth and improved survival rates. The research also demonstrated that the platform converted tumors that typically evade the immune system into ones that were more susceptible to attack. The effectiveness of the platform was further validated in humanized mouse models using immune cells from donors who had received a COVID-19 vaccine.
“The preclinical data exceeded our expectations. PROTEXI not only enhanced tumor-specific immune responses but also reshaped the tumor microenvironment, expanded immune memory, and improved responses in models resistant to current therapies,” said Seunghwan Lim, vice president of research and operations at Celloram Inc, in a news release.
The study found that the platform uses pre-existing antiviral CD4+ helper T-cell immunity to strengthen tumor-specific CD8+ cytotoxic T-cell responses. This mechanism allows for a more coordinated and durable antitumor response compared to conventional dendritic cell vaccines, according to the researchers.
“For decades, researchers have recognized the importance of helper T cells in generating durable antitumor immunity, yet identifying clinically useful helper signals has remained a major challenge,” said John Letterio, director of the angie fowler adolescent and young adult cancer institute at University Hospitals Rainbow Babies & Children’s Hospital and co-leader of the developmental therapeutics program of the Case Comprehensive Cancer Center, in a news release.
Celloram and University Hospitals Cleveland Medical Center are now moving the platform toward first-in-human clinical trials. The upcoming study will focus on patients with sarcoma to evaluate the safety and immunologic activity of the personalized vaccine approach. Researchers suggested that if the trials are successful, the platform could eventually be applied to a wide range of therapy-resistant cancers.
“What is particularly elegant about PROTEXI is that it leverages one of the most powerful biological resources already present within the human population: pre-existing antiviral immune memory,” said Seong-Jin Kim, co-founder of Celloram and chairman of MedPacto Inc, in a news release.
The research was supported by the Case Comprehensive Cancer Center and the National Cancer Institute of the National Institutes of Health (NIH).
