Distributed Manufacturing, Foreign Establishments, and Why the FDA's New Proposed Rule Matters to Clinical Pharmacology

On July 13, 2026, the United States Food and Drug Administration (FDA) published a proposed rule amending 21 CFR Part 207, the drug establishment registration and listing regulations. ¹ The rule does two things. First, it creates a new registration pathway for “distributed manufacturing establishments” (DMEs). DMEs are basically hub‐and‐spoke operations in which a single quality unit oversees distributed manufacturing units (DMUs) that can be added, removed, or physically relocated across multiple sites, potentially in different countries, without each one requiring a separate registration. Second, it aligns FDA's foreign establishment registration and listing requirements with the PREVENT Pandemics Act, closing a gap in which an active pharmaceutical ingredient (API) manufacturer that shipped only to other foreign sites had, in practice, remained invisible to the Agency even when its material eventually reached the United States as finished product. ¹ This rule warrants the attention of our readers, not only those in Chemistry, Manufacturing, and Controls (CMC) and regulatory affairs but also clinical pharmacologists more generally, given its broader implications for the field. The FDA is accepting comments on the proposed rule through September 11, 2026.

Distributed Manufacturing and the Question of “Equivalence”

Distributed manufacturing has been building toward this moment since the FDA named it a priority technology under its Framework for Regulatory Advanced Manufacturing Evaluation (FRAME) initiative, followed by a 2022 discussion paper, a public workshop, and a 2023 stakeholder action plan. ² , ³ , ⁴ The appeal is real: mobile or geographically distributed units that are “equivalent in design and operation” can be surged to where demand exists, which matters for shortage‐prone sterile injectables, cell and gene therapy starting materials, and emergency countermeasures. ¹ Critically, the proposed rule does not require DMUs to be identical, only equivalent. The FDA deliberately leaves the concept of “equivalent” in this context open for the field to help calibrate. ¹

That is where clinical pharmacology has a stake. We have long owned the question of what counts as pharmacokinetically indistinguishable when something about how a product is made changes. Distributed manufacturing pushes that question into a more dynamic setting: not whether a post‐approval site changed, but whether a unit that relocated last month still behaves, in vivo, like the sibling unit that never moved. FDA's own preamble flags this directly, noting that relocation introduces independent factors such as climate, utilities, or local conditions that could affect a unit's equivalence, and that this equivalence “would need to be evaluated and confirmed prior to manufacturing at the new location and through continued validation and monitoring.” ¹ For products in early clinical development manufactured under a decentralized strategy, that evaluation will draw on the same bridging and comparability logic that clinical pharmacology has long applied to bioequivalence, only now applied across a mobile, multi‐site network rather than a fixed plant.

Foreign Establishment Registration and the Material We Dose

The second part of the rule is less novel conceptually but no less relevant. As of late 2024, nearly 60% of registered drug establishments were located outside the United States, and the FDA's preamble acknowledges that many API manufacturers supplying only other foreign sites have simply never registered, even when their material eventually crosses the US border. ¹ For early‐phase clinical pharmacologists, API sourcing is not an abstraction as it underlies every impurity qualification and every claim in a first‐in‐human protocol about what is actually being dosed. Better visibility into that supply chain strengthens the ground on which dose‐escalation decisions and safety margins already rest.

The FDA proposal is timely because the drug ecosystem has outgrown the assumptions embedded in older registration frameworks. According to the FDA's agenda description, the rule would clarify that foreign drug manufacturing establishments may be subject to registration and listing requirements even when they do not directly import or offer products for import into the United States, and it would create registration requirements for establishments engaged in distributed manufacturing. For clinical pharmacologists, this is not merely an administrative adjustment; it is an acknowledgement that modern development and supply chains are networked, modular, and often geographically dispersed.

That matters because the scientific risk profile of a drug is inseparable from where and how it is made. Distributed manufacturing can improve resilience, shorten lead times, and support localized production, but it also introduces questions about comparability, process control, batch genealogy, and change management that are highly relevant to exposure–response interpretation and product consistency. The agency's current registration and listing infrastructure already supports inspection planning, recall execution, postmarket surveillance, supply‐chain resiliency, and counterterrorism. The proposed rule appears designed to make those functions more complete in a world where manufacturing is no longer a single‐site concept.

For clinical pharmacology, the practical implication is improved traceability across the product lifecycle. When registration and listing data are current, regulators and sponsors can more readily connect a marketed product to its manufacturing history, site network, and labeling state, which in turn helps interpret unexpected safety signals, performance drift, or geographic differences in product behavior. This is especially important as the field increasingly relies on model‐informed drug development, decentralized clinical operations, and faster post‐approval iteration.

The proposal also raises an important question for sponsors: who owns the truth about the product? The FDA's existing framework makes clear that establishments must register and list, with updates required on a defined schedule, and that the resulting database supports the Drug Establishments Current Registration Site and the National Drug Code ecosystem. As manufacturing models become more fragmented, clinical pharmacologists may need to think of registration and listing as part of the evidence base that underwrites product credibility, not as a post‐manufacturing clerical task.

What This Means for Clinical Pharmacology

If a product intended for first‐in‐human or dose‐range studies is, or may later be, manufactured under a decentralized strategy, comparability assessments belong in the development plan from the outset, not retrofitted once a DMU relocates. Physiologically based pharmacokinetic modeling has matured enough in current regulatory practice to support bridging arguments for manufacturing changes without new clinical studies in many circumstances, ⁵ and a framework built around “equivalent, not identical” units is a natural extension of that logic. The field of clinical pharmacology should help the FDA calibrate when such evidence can substitute for a dedicated bridging study following a DMU relocation, and when it cannot. Equivalence in design is not the same as equivalence in performance, and that gap is precisely where clinical pharmacology earns its keep.

For the clinical pharmacology community, this rule should be read as part of a larger shift: the science of therapeutics is moving from product‐centric development toward ecosystem‐centric assurance. The best dose‐selection strategy can still be undermined by weak manufacturing visibility, and the best pharmacometric model cannot compensate for poor traceability in the commercial supply chain. In that sense, registration and listing are not peripheral compliance requirements; they are part of the scaffolding that allows clinical pharmacology to translate into dependable patient care.

I encourage readers to review the proposed rule, consider whether it touches programs that they are working on, and weigh in during the comment period. I also welcome submissions to this journal on comparability, bridging, and early‐phase trial design.

Funding

No funding was obtained for this work.

Conflicts of Interest

The author declares no conflicts of interest.