Biosimilars as antivirals: scientific and regulatory readiness for rapid, cost-effective deployment in infectious threats

INTRODUCTION: Rapid and equitable access to antiviral biologics in outbreaks is constrained by bespoke manufacturing, lengthy trials, and uneven procurement. Biosimilar antivirals could change responsiveness from single-source supply to multi-manufacturer preparedness if regulatory and chemistry, manufacturing, and controls (CMC) platforms are leveraged. AREAS COVERED: Evidence on antiviral biologic classes, orthogonal analytics, critical quality attributes, pharmacokinetic/pharmacodynamic (PK/PD) biomarkers, regulatory convergence, value assessment, and manufacturing scale-up is summarized. Platform CMC and tech-transfer enablers (e.g. single-use, modular/distributed facilities) are described alongside integration of dynamic transmission models with distributional cost-effectiveness analysis to address equity. The review evaluates how high-resolution analytical similarity, combined with comparative clinical pharmacology, can reduce the need for comparative clinical efficacy studies in selected programs. paradigm. Databases and regulatory/health technology assessment portals were searched from January 2010 to 10 October 2025. Predetermined criteria with structured extraction and consensus resolution were utilized for dual screening. EXPERT OPINION: The field is moving toward PK/PD-anchored, analytics-first pathways that, with thorough mapping of structure - function relationships, may limit the need for Phase III trials. Pre-specified PD/analytic packages are provided for each modality/virus, along with reference product batch libraries, bridging plans, reliance agreements, and standing commission regulations to operationalize this approach in an emergency.