Agentic Workflow Drift in Life Sciences: Extending the Reasoning-Layer Risk Taxonomy to GxP-Regulated Pharmaceutical and Biotechnology Operations

Agentic AI is beginning to support regulated activities across pharmaceutical manufacturing, biotechnology, pharmacovigilance, clinical development, and regulatory affairs through emerging copilots, autonomous workflow orchestration, and AI-assisted quality operations. In these settings, consequential determinations turn on the operational meaning of regulated terms, whether a deviation is critical, whether an adverse event is serious, whether a batch may be released, whether a subject is eligible. These deployments change where regulated operational decisions are formed. Rather than executing predetermined logic alone, autonomous agents increasingly reconcile multiple validated sources to determine what a regulated term means at runtime, and act on the resolved interpretation without a qualified reviewer resolving it first. Every checkpoint clears, every system performs as designed, and the organization is still wrong. This shift introduces a distinct governance exposure. Agentic Workflow Drift is the mechanism by which agentic systems satisfy mandatory validation checkpoints while executing under an unauthorized operational interpretation, producing outcomes that are procedurally compliant and substantively wrong. The analysis distinguishes the reasoning layer within the GxP control environment, demonstrates that computer system validation, 21 CFR Part 11 controls, data integrity programs, and quality management system review each govern an artifact that exists before or after the moment of interpretation, and shows that none governs the interpretation itself as a distinct object. The same reasoning surface also permits deliberate manipulation. That deliberate form is Agentic Workflow Subversion, treated here as a distinct and serious exposure, because in medical research and manufacturing the deliberate steering of an agent's resolved interpretation can influence batch release, safety reporting, and trial eligibility, and through them patient safety and product quality. The concepts translate naturally into established GxP practice, mapping the Reasoning Baseline, the Semantic Deviation Index, and the Deterministic Gate onto established GxP concepts such as predetermined acceptance criteria, review by exception, and quality-controlled definitions, rather than replacing the validation disciplines already familiar to regulated organizations.