From Priority Need to Evidence-to-Action: A Structured Narrative Review of Six Purposefully Selected Anti-Infective Innovations

Regulatory approval establishes an initial benefit–risk judgment but does not show whether an anti-infective innovation will reach eligible patients, retain benefit in routine care, or preserve future treatment options. We conducted a structured critical narrative review of six purposefully selected, nonrepresentative exemplars: ceftazidime/avibactam, cefiderocol, long-acting cabotegravir/rilpivirine, nirmatrelvir/ritonavir, bedaquiline–pretomanid–linezolid with or without moxifloxacin, and letermovir. The scope covered qualifying approvals from January 2015 to 12 August 2026. An iterative working registry contained 371 publication records; 44 publications underwent detailed extraction and appraisal, with authoritative documents supporting regulatory and guideline interpretation. Related reports were clustered, and comparisons considered population, treatment strategy, comparator, outcome, follow-up, and epidemiologic context. Across the exemplars, the principal decision problem shifted from initial activity to mechanism-specific treatment, delivery infrastructure, contemporary absolute benefit, regimen optimization, or prevention beyond treatment cessation. Apparent disagreement between early and later evidence could reflect different questions, residual bias, or unresolved biological variation rather than failed replication. Access and diagnostic turnaround conditioned the benefit achievable outside specialized programs. Documentary mapping distinguished explicit action linkage, qualified guideline linkage, incorporation of evidence into guidance without demonstrated recommendation change, and untraced pathways. The review contributes a comparative synthesis rather than new primary data or a validated scoring framework. Its findings support post-approval programs that connect causal comparisons, patient-important outcomes, microbiology, equitable reach, and clearly documented decision pathways, while avoiding generalization from six selected examples to all anti-infective innovations.