EU MDR Compliance: What Changed from the MDD

The EU Medical Device Regulation, Regulation (EU) 2017/745 (“MDR”), replaced the Medical Device Directive, Council Directive 93/42/EEC (“MDD”), and its sibling for active implantables, the Active Implantable Medical Devices Directive (90/385/EEC), becoming fully applicable on 26 May 2021. Most guidance written about “EU MDR” describes the finished regime as if it always looked this way. It didn’t — and for a manufacturer whose quality system, technical file and supplier contracts were built around the MDD, what actually changed matters more than what the current rules say in isolation, because a legacy MDD-era program has specific gaps to close, not a blank slate to fill.

A regulation, not a directive — and why that distinction is not just legal trivia

The MDD was a directive: EU member states transposed it into national law, and implementation varied at the margins from one member state to the next. The MDR is a regulation — directly applicable in every member state with no national transposition step, which is precisely why it could add EU-wide mechanisms the MDD never had, like a single central device database and a named compliance role inside every manufacturer. The practical shift for anyone with an existing MDD program: national-level interpretation differences you may have relied on largely disappear, and several obligations that used to sit implicitly with “the manufacturer” now attach to a specific, MDR-created role or system.

What exists under the MDR that had no MDD counterpart

These are not tightened versions of MDD requirements — they are new obligations the MDD never imposed at all.

• The Person Responsible for Regulatory Compliance (PRRC). Article 15 MDR requires every manufacturer to have at least one named, qualified individual responsible for technical-documentation conformity, post-market surveillance and vigilance oversight, and regulatory-registration duties — for a manufacturer with no EU establishment, that obligation falls to its authorised representative instead. The MDD had nothing equivalent; a handful of member states had informal national “safety officer” expectations, but Article 15 is the first EU-wide, legally mandated version of the role.
• EUDAMED. The MDD had no central EU device database. The MDR created one — six modules covering actor registration, UDI/device registration, notified bodies and certificates, market surveillance, clinical investigations, and post-market surveillance/vigilance — phased in separately over several years rather than switched on at once. See CASRAI’s module-by-module EUDAMED status guide for exactly which modules are mandatory right now.
• A formal Unique Device Identification system. The MDD had no UDI requirement of any kind. The MDR mandates a UDI on the device or its packaging and registration of that identifier in EUDAMED’s UDI/DEV module, the traceability mechanism a recall or field safety corrective action now runs on. See CASRAI’s UDI guide for carrier formats and the basic-UDI-DI concept.
• Four additional Annex VIII classification rules. The MDR’s risk-based classification annex carries rules with no MDD equivalent, extending classification into device categories the MDD’s older rule set simply didn’t address. A device that classified one way under the MDD is not guaranteed the same class under the MDR — reclassification, usually upward, is common enough that it needs to be checked explicitly rather than assumed. CASRAI’s EU MDR Classification Rules guide walks all 22 Annex VIII rules.
• Scrutiny and unannounced audits. The MDR added a formal scrutiny procedure for certain high-risk devices’ clinical evaluation, and requires notified bodies to run unannounced factory audits on a defined cycle — oversight mechanisms the MDD’s notified-body regime did not include. See CASRAI’s notified body designation and audits guide.

The clinical evidence bar moved, even for devices that didn’t change

The MDD allowed a broad equivalence route: a manufacturer could rely heavily on another device’s published clinical data if it could argue technical, biological and clinical equivalence. The MDR keeps the equivalence route but narrows it substantially for Class III and implantable devices, generally requiring the manufacturer to have direct contractual access to the equivalent device’s own technical documentation rather than relying on published literature alone. That single change is why a number of legacy MDD-cleared devices — unchanged in design — have needed genuinely new clinical evidence to requalify under the MDR. CASRAI’s guides on the Clinical Evaluation Report, PMCF plan and post-market surveillance plan cover what MDR-level evidence actually has to contain.

MDD vs MDR: the practical delta, side by side

Area	Under the MDD	Under the MDR
Legal instrument	Directive — national transposition, some cross-country variance	Regulation — directly applicable, uniform EU-wide
Named compliance role	None required	PRRC required (Art. 15)
Central device database	None	EUDAMED, phased in by module
Device identification	No UDI requirement	UDI mandatory, registered in EUDAMED
Classification rules (Annex)	Fewer rules; some device categories unaddressed	Four additional rules; reclassification common
Equivalence route for clinical evidence	Broad; published literature often sufficient	Narrowed for Class III/implantables; contractual access to the equivalent device’s file generally required
Notified body oversight	Periodic surveillance audits	Adds scrutiny procedure and unannounced audits
Post-market obligations	Vigilance reporting	Adds a formal PMS plan, PSUR, and (for higher-risk devices) a PMCF plan

The extended transition deadlines — who still has time, and how much

Regulation (EU) 2023/607, in force since 20 March 2023, amended MDR Article 120 to extend how long a device can keep being placed on the market under a valid MDD or AIMDD certificate while its MDR conformity assessment is still underway. The extended dates run by device class:

Device category	Extended deadline
Class III custom-made implantable devices	26 May 2026
Class III devices and implantable Class IIb devices	31 December 2027
Non-implantable Class IIb devices, Class IIa, Class Is and Class Ir devices, and Class I devices reclassified upward under the MDR	31 December 2028

The extension is conditional, not automatic: it applies only to devices that held a valid MDD/AIMDD certificate as of 26 May 2021 (or one issued afterward that remained valid), and the manufacturer had to have a signed written agreement with an MDR notified body in place by 26 September 2024, plus a formal MDR certification application submitted by 26 May 2024. A device whose design or intended purpose changes significantly during this window loses the extension. Regulation 2023/607 also removed the MDR’s original “sell-off” deadline — a device already placed on the market can continue to be made available or put into service until its certificate’s revised expiry or the device’s own shelf life, without a separate cut-off date. Manufacturers relying on this extension for continued compliance work should track it alongside CASRAI’s field safety corrective action and complaint handling guides, since both regimes’ reporting obligations apply throughout the extended window, not just after full MDR certification.

What a legacy MDD-era program should actually check right now

• Confirm which extended deadline actually applies to each device by its current MDR classification, not its old MDD classification — reclassification changes which row of the table above applies.
• Confirm the notified body agreement and application deadlines above were genuinely met and documented; missing either one forfeits the extension regardless of certificate validity.
• Name a PRRC and document the role formally — this has no grace period tied to the transition deadlines above.
• Check EUDAMED module status against CASRAI’s EUDAMED guide; actor registration and UDI/device registration are the modules most likely to already be mandatory.
• Re-run the device through the current Annex VIII classification rules rather than assuming the MDD-era class still applies.

Frequently asked questions

Does the MDR extension mean I don’t need to do anything until 2027 or 2028?

No. The extension only postpones the deadline for holding a full MDR certificate on devices that already had a valid MDD/AIMDD certificate and met the notified-body-agreement and application deadlines above. Vigilance reporting, post-market surveillance, PRRC designation, and EUDAMED registration obligations that are already in force apply now, regardless of which extended deadline a device’s certificate falls under.

Is every device automatically eligible for the extended deadline?

No. Eligibility depends on the device having held a valid MDD/AIMDD certificate as of 26 May 2021 (or one issued after that date that stayed valid), a signed notified body agreement by 26 September 2024, a submitted MDR application by 26 May 2024, and no significant change to the device’s design or intended purpose in the meantime. A device that fails any one of those conditions does not get the extension.

Did the MDD’s classification of my device carry over to the MDR automatically?

Not necessarily. The MDR’s Annex VIII adds classification rules the MDD didn’t have, and several device categories reclassify upward under the new rule set. Confirming current MDR classification is a required step, not an assumption to make from the old MDD class.

What happened to the MDD’s “sell-off” period?

Regulation (EU) 2023/607 removed it. Devices already placed on the market can continue to be made available or put into service until the certificate’s revised expiry date or the device’s own shelf life runs out, rather than a fixed sell-off cutoff separate from that.

Is the AIMDD (active implantable devices directive) part of this same transition?

Yes. The MDR repealed both the MDD (93/42/EEC) and the AIMDD (90/385/EEC), and the extended transition deadlines under Regulation 2023/607 apply to certificates issued under either directive.

Related CASRAI resources

• Laboratory Compliance & Quality — the full cluster overview.
• EU MDR Classification Rules (Annex VIII) — all 22 rules that set a device’s class.
• EUDAMED — module-by-module mandatory-use status.
• UDI Medical Device — FDA and EU unique device identifier requirements.
• EU Authorised Representative (Article 11) — the parallel MDR-created role for non-EU manufacturers.
• Notified Body Designation and Audits Under MDR/IVDR — the scrutiny procedure and unannounced-audit cycle.
• Clinical Evaluation Report Under EU MDR — the narrowed equivalence route in detail.
• PMCF Plan Under EU MDR — ongoing clinical evidence obligations.
• Field Safety Corrective Action — FSCA vs recall vs field safety notice, EU/US cross-walk.
• IVDR (EU 2017/746) — the parallel regulation for in vitro diagnostics.
• ISO 13485 — the QMS standard MDR conformity assessment is built around.