A new industry analysis highlighted that the biggest barriers for mRNA neoantigen cancer vaccines are less about clinical efficacy and more about scaling production. Personalized vaccines require “n-of-1” manufacturing, chain-of-identity tracking, and batch-specific purification. The piece uses the recent Merck and Moderna personalized melanoma Phase 3 results as context, noting that only topline outcomes have been released so far, while commercialization depends on manufacturing throughput and process validation for tens of thousands of patient-specific units. 4basebio CEO Amy Walker emphasized that the industry must “scale out vs scale up,” shifting from conventional batch production logic to a manufacturing architecture built for many individualized batches. For biotech operators and investors, the operational bottleneck could determine which programs reach market readiness first, even when the clinical readout is strong.