Shorthand for a medicine individualized to a single patient. In cancer vaccines it describes an N-of-1 product tested in an ordinary cohort trial — not a single-patient trial design.
The phrase is used two ways. A true N-of-1 trial is a study design: one patient cycled through treatment and control, where N=1 is literally the sample size. A personalized cancer vaccine is something different — an N-of-1 product: each patient gets a uniquely sequenced vaccine, but it is tested in a conventional, multi-patient, randomized trial. Read "N-of-1 cancer vaccine" as a statement about manufacturing, not about statistics.
Why it matters for the digest: an individualized product collides with a regulatory and reimbursement system built around one fixed, reproducible drug. How regulators resolve that — by validating the process rather than the molecule — is the gating question for whether these vaccines become approved, payable products.