Dana-Farber Cancer Institute researchers have demonstrated that a modified version of their personalized cancer vaccine generates significantly stronger immune responses in melanoma patients compared to previous formulations. The phase 1 clinical trial results, published in Cell, show that the updated NeoVaxMI vaccine is safe, feasible, and produces enhanced vaccine-specific immune responses.
Enhanced Vaccine Formulation Shows Promise
The NeoVaxMI vaccine builds upon the original NeoVax platform developed by Patrick Ott, MD, PhD, clinical director of the Melanoma Disease Center at Dana-Farber, and Catherine Wu, MD, chief of the Division of Stem Cell Transplantation and Cellular Therapies. The enhanced formulation adds Montadine, an immune-boosting compound, to the existing combination of personalized neoantigens and poly-ICLC immunostimulant.
"We believe that the immunogenicity of current personalized cancer vaccines, considered critical for their effectiveness, can be improved substantially," says Ott. "This study provides evidence showing that changes in formulation and administration improve the power of the vaccines."
Comprehensive Immunotherapy Approach
The trial enrolled patients with previously untreated advanced or high-risk melanoma, with the primary goal of fully vaccinating all participants and conducting in-depth immune response analysis. The treatment protocol incorporated three therapeutic components: patients received systemic nivolumab before, during, and after the vaccine series, along with local ipilimumab administration at vaccination sites.
The addition of subcutaneous ipilimumab delivery was specifically designed to enhance T cell activation in response to vaccine-introduced antigens. Systemic nivolumab, a standard of care therapy for resected or advanced melanoma, reduces immune suppression throughout the treatment period.
Robust Immune Response Data
All nine fully vaccinated patients demonstrated T cell responses to neoantigens when researchers isolated T cells from blood samples and tested their ability to recognize vaccine-specific neoantigens. Notably, six of nine patients showed cytotoxic responses by CD8+ T cells, a critical component of anti-cancer immunity.
"These observations of ex vivo CD8+ T cell responses are what we want to see in a vaccine, and we were excited to see this important aspect of a cancer vaccine-induced immune response on the current trial," says Ott.
Advanced Analysis Reveals Tumor Infiltration
Using leading-edge single cell sequencing approaches, investigators analyzed skin biopsies from vaccine and ipilimumab injection sites. The analysis revealed increased macrophage populations after vaccination, suggesting that NeoVaxMI effectively primed the injection site environment for immune activation.
"The right environment at the injection site to trigger the immune cells to begin an immune activation cascade is critical," says Ott.
The research team also demonstrated that vaccination induced different T cell receptor patterns compared to standard nivolumab treatment alone. The number of distinct vaccine-specific T cell types activated after vaccination exceeded those produced by nivolumab treatment, indicating a potent vaccine-induced immune response.
Crucially, using new single-cell interrogation technologies, researchers confirmed that vaccine-induced T cells successfully infiltrated tumors in four patients with available tumor samples.
Safety Profile and Future Implications
NeoVaxMI demonstrated a favorable safety profile without introducing new safety concerns. The vaccine was well tolerated across all participants in the small phase 1 cohort.
"These are exciting observations showing that this new formulation and delivery strategy improves the power of the vaccination," says Ott. "The methods we used to measure the immune responses are rigorous and unique in the field in the setting of a clinical trial. Studies like this are important if we want to continue to improve personalized cancer vaccines."
The study's limitations include its small size and the simultaneous introduction of three new agents, making it challenging to attribute specific improvements to individual vaccine modifications. However, the comprehensive immune response data provides strong evidence for the enhanced vaccine's potential in personalized cancer immunotherapy.
