The Immune System That Could Not See the Tumour
Cancer cells arise from the accumulation of somatic mutations in the DNA of normal cells, and each tumour carries a unique mutational signature whose protein products, called neoantigens, are expressed on the cancer cell surface in ways that distinguish the cancer cell from the normal cells from which it arose. In principle, the immune system should recognise these neoantigen-presenting cancer cells as abnormal and mount a cytotoxic T cell response that eliminates them, and in some patients this immune surveillance does operate to control tumour growth. The clinical reality is that most established tumours have evolved mechanisms to evade immune recognition, suppressing the T cell response through checkpoint inhibitor pathways, reducing neoantigen expression, and creating the immunosuppressive tumour microenvironment that prevents effective immune attack. The commercial development of immune checkpoint inhibitor drugs targeting PD-1, PD-L1, and CTLA-4 has restored T cell activity in a subset of patients whose tumours are immunogenic, producing the durable responses in melanoma, lung cancer, and other tumour types that have made checkpoint inhibitors the most commercially successful oncology drug class of the past decade. But checkpoint inhibitor response rates in most tumour types are below fifty percent, and the patients whose tumours do not respond lack the T cell clones reactive to their tumour's specific neoantigens that checkpoint inhibition requires to produce an anti-tumour response.
Personalised cancer vaccines address the fundamental limitation of checkpoint inhibitor-only immunotherapy by actively generating the neoantigen-specific T cell clones that the tumour has prevented from developing spontaneously. The process begins with sequencing both the tumour's DNA and the patient's normal tissue DNA to identify the mutations unique to the tumour, predicting which of the resulting mutant peptides will be presented on the patient's specific HLA molecules and therefore visible to T cells, and synthesising a vaccine encoding the selected neoantigens in a format that elicits a potent T cell response. The mRNA format, whose manufacturing speed and flexibility was demonstrated by the COVID-19 vaccine programmes that produced authorised vaccines within eleven months of the SARS-CoV-2 sequence being published, has enabled personalised cancer vaccine production timelines that compress the neoantigen selection to vaccine delivery timeline to weeks rather than the months that peptide vaccine manufacturing required in earlier personalised vaccine approaches.
Moderna and Merck's Phase Three Data
The Phase 2b clinical trial data from Moderna's mRNA-4157 personalised neoantigen vaccine combined with pembrolizumab checkpoint inhibition in resected high-risk melanoma, reported in 2023 and followed by updated data in subsequent years, demonstrated a forty-four percent reduction in the risk of recurrence or death compared with pembrolizumab alone in patients with high-risk stage three and four melanoma who had undergone surgical resection. This result, whose magnitude and statistical significance exceeded the pre-trial expectations of many in the oncology clinical community, was the commercial inflection point that transformed personalised cancer vaccines from a promising research concept into a commercially validated clinical approach whose regulatory approval path has now been opened by the Phase 3 trial that Moderna and Merck are conducting. The commercial implications of a positive Phase 3 result extend beyond melanoma to the multiple other solid tumour indications where the combination of surgical resection, personalised vaccine, and checkpoint inhibition might improve the disease-free survival outcomes that oncology's standard of care has not meaningfully improved for decades.
BioNTech's personalised cancer vaccine programme, whose BNT111 neoantigen vaccine in melanoma and BNT122 pancreatic cancer vaccine are in clinical development, represents the alternative mRNA manufacturing platform whose COVID-19 vaccine success demonstrated the speed and scalability that personalised vaccine production requires. The pancreatic cancer application of personalised vaccines is commercially significant because pancreatic ductal adenocarcinoma is among the malignancies with the worst prognosis and the most limited treatment options, and the preliminary clinical data from BioNTech's pancreatic cancer personalised vaccine trial showing immune responses to personalised neoantigens in the majority of treated patients has created substantial clinical excitement about whether personalised vaccination can improve outcomes in a disease where conventional chemotherapy provides only modest survival benefit.
Manufacturing at Personalised Scale
The commercial challenge of personalised cancer vaccines is the manufacturing model that personalised medicine requires. Each patient's vaccine encodes a unique neoantigen sequence derived from their specific tumour's mutational profile, making the vaccine a unique drug product that cannot be manufactured in advance and must be produced on demand within the timeframe that clinical use requires. The bioinformatics pipeline that identifies and ranks neoantigens from tumour sequencing data, the mRNA synthesis platform that manufactures the personalised construct, and the quality control testing that verifies the product before patient administration must all operate at the speed that clinical turnaround requires while meeting the regulatory quality standards that a licensed drug product demands. The industrialisation of this personalised manufacturing process, whose per-patient cost must ultimately reach levels that reimbursement frameworks can support, is the commercial development challenge that the personalised cancer vaccine developers are investing in alongside their clinical programmes.
Top 10 Companies in Personalised Cancer Vaccines Globally
- Moderna: US mRNA company with mRNA-4157 personalised neoantigen vaccine in Phase 3 trial for high-risk melanoma in combination with Merck's pembrolizumab; its forty-four percent recurrence risk reduction in Phase 2b and its Merck co-development partnership create the most commercially advanced personalised cancer vaccine programme and the one whose regulatory approval would establish personalised vaccination as a standard oncology treatment category.
- BioNTech: German mRNA company with BNT111 melanoma and BNT122 pancreatic cancer personalised vaccine programmes; its mRNA manufacturing infrastructure from COVID-19 vaccine production and its Genentech collaboration for pancreatic cancer create the alternative mRNA personalised vaccine platform whose clinical diversity across tumour types is broader than any other developer.
- Merck: US pharmaceutical company co-developing mRNA-4157 with Moderna and providing pembrolizumab whose checkpoint inhibition combines with personalised vaccination to produce the clinical efficacy that neither treatment achieves alone; its oncology commercial infrastructure and its global regulatory relationships create the commercialisation capability that Moderna's vaccine technology requires to reach patients worldwide.
- Neon Therapeutics (BioNTech): US personalised neoantigen vaccine pioneer acquired by BioNTech whose neoantigen prediction algorithms and clinical trial experience in personalised vaccine development informed the BioNTech personalised vaccine programme; its scientific heritage in neoantigen biology creates the intellectual foundation for BioNTech's personalised vaccine approach.
- Gritstone Bio: US personalised cancer vaccine company with GRANITE self-amplifying RNA neoantigen vaccine approach; its self-amplifying RNA technology that produces more antigen per dose than conventional mRNA and its colorectal cancer and lung cancer programmes create the personalised vaccine platform differentiation that distinguishes it from Moderna and BioNTech's lipid nanoparticle mRNA approaches.
- Inovio Pharmaceuticals: US DNA vaccine company with personalised neoantigen vaccine programmes using electroporation delivery of plasmid DNA encoding tumour-specific antigens; its DNA vaccine platform whose room temperature stability advantage over mRNA creates the distribution logistics benefit that global oncology application of personalised vaccines would require in markets without ultra-cold chain infrastructure.
- Nousbiotherapeutics: UK personalised cancer vaccine company using personalised adenovirus-based neoantigen vaccines; its gorilla adenovirus vector platform and its T cell immunogenicity focus create the non-mRNA personalised vaccine approach whose clinical immune response data in colorectal cancer demonstrates the technology's neoantigen-specific T cell generation capability.
- Agenus: US immuno-oncology company with neoantigen vaccine programmes and checkpoint antibody development; its ATLAS neoantigen identification platform and its combination of personalised vaccination with its own checkpoint inhibitor antibodies create the integrated neoantigen immunotherapy company whose vertical integration from vaccine to checkpoint inhibitor distinguishes it from the mRNA platform companies dependent on Merck's pembrolizumab combination.
- Vaccinex: US company with VX15 semaphorin 4D antibody in combination with personalised neoantigen vaccination; its approach combining neoantigen vaccination with a tumour microenvironment-modifying antibody that reverses the immunosuppression preventing T cell entry creates the combination immunotherapy approach that the tumour microenvironment barrier to vaccine efficacy motivates.
- Immatics: German cancer immunotherapy company with personalised tumour-associated antigen approaches using its XPRESIDENT target discovery platform; its HLA-presented peptide identification technology and its ACTengine adoptive cell therapy programmes create the complementary personalised cancer treatment approaches that pair with vaccine-based immunotherapy in the combination treatment strategies that oncology's future is moving toward.