Abstract
Background: With mRNA vaccines, cancer immunotherapy is changing to an entirely different
ballpark. These vaccines enable rapid prototyping and simultaneous antigen presentation to
stimulate strong responses from both CD8+ and CD4+ T cells. This review aims to integrate the
current developments and the future direction of this developing technology.

Key Advances: Constructing an effective vaccine clinically useful was made possible by the
sequential advancements in technology, such as nucleoside modifications (e.g., pseudouridine) to
enhance stability and translation, codon and UTR sequence optimization, and lipid nanoparticle
(LNP) delivery systems to ensure in vivo uptake. Such advancements make constructing off-the
shelf and bespoke neoantigen vaccines possible.

Clinical Impact: Personalized mRNA vaccines have been effective when combined with immune
checkpoint inhibitors. In the case of resected melanoma, the combination of mRNA-4157 and
pembrolizumab reduced the risk of recurrence by 44% (HR=0.56). BNT122's recurrence-free
survival at 18 months was 79%. There is a similar indication of efficacy for pancreatic cancers and
microsatellite-stable colorectal cancers.

Challenges and Future Directions: Persisting issues include the variability of tumors,
immunosuppressive microenvironments, inefficiency of LNP (such as hepatic sequestration), and
complicated, high-cost manufacturing (>$100,000/dose). AI antigen prediction, next-generation
delivery platforms for targeted lymphoid tissue accumulation, and combination strategies with
stromal modulators will be critical to address in the future. To enhance global access, innovations
in manufacturing at scale and prophylactic vaccination for high-risk populations are required.

Conclusion: Taking into account the regulatory approvals and the ongoing Phase-III trials, it
seems that mRNA vaccines will soon lead to a breakthrough in personalized oncology, shifting the
paradigm of treatment from immediate intervention to chronic care and prevention.

Key words: mRNA vaccine; cancer immunotherapy; neoantigen; lipid nanoparticles; personalized medicine; immune checkpoint blockade.