Sequence-Anchored Shared Tumor-Specific Epitopes for Pre-Manufactured HLA-Matched mRNA Cancer Vaccine Libraries: A...

Area of Science:

• Oncology
• Immunology
• Vaccine Development

Background:

• A single cancer vaccine is insufficient for all patients.
• Recurrent tumor-specific epitopes offer a strategy for developing targeted mRNA vaccines.
• Pre-manufactured, HLA-matched vaccines can be tailored for molecular subgroups.

Purpose of the Study:

• To define and present sequence-anchored reference designs for shared tumor-specific epitopes.
• To establish criteria for identifying viable tumor-specific targets for vaccine development.
• To categorize potential neoantigens into viral oncoproteins, driver mutations, hematologic neoantigens, and fusion junctions.

Main Methods:

• Defined shared tumor-specific epitopes using a rigorous cancer-cell-only criterion.
• Identified recurrent peptides from viral oncoproteins, driver mutations, frameshifts, altered C-termini, and fusion junctions.
• Developed fifteen sequence-anchored reference designs and one placeholder across thirteen candidates.

Main Results:

• Presented reference designs for viral oncoproteins (HPV16/18 E6/E7, Merkel cell polyomavirus), driver neoepitopes (KRAS, IDH1, H3 K27M), hematologic neoantigens (NPM1, CALR), and fusion junctions (EWS-FLI1, BCR-ABL).
• Ensured targets were recurrent, absent from essential normal tissues at the peptide-HLA level, naturally presented on tumor cells, and sufficiently clonal.
• Provided representative ORFs anchored to canonical accessions with documented events.

Conclusions:

• The presented designs are reference constructs requiring independent validation and safety assessments.
• These designs are not clinical-grade products but form a governed library for specific contexts.
• Historical vaccination data highlights both potential and limitations, with no current proof-of-benefit for these specific designs.