CDx Consultation Under IVDR: The 60-Day Procedure That Determines Your Market Access

She's reading the same paragraph for the third time.

Not because it's complicated — because it's circular. The IVDR says the Notified Body must seek a scientific opinion on the "suitability" of the companion diagnostic "in relation to the medicinal product." But what does "suitability" actually mean in practice?
What goes into the dossier? Who decides which authority to consult? And what happens when performance data changes after the initial opinion?

The answers aren't buried — they're scattered. Across Article 48 of the IVDR, Annex IX Section 5.2, Annex X Section 3(k), and separate EMA procedural guidance documents that have been revised multiple times since 2022.

What follows pulls those threads together into a single, navigable framework — the kind of clarity the regulation itself doesn't provide.

What the EMA Q&A Actually Covers

Why this matters: The EMA Q&A sections on companion diagnostics address the procedural gaps that the IVDR itself leaves open — particularly around which authority to consult, what to include in the dossier, and how follow-up consultations work.

The IVDR establishes the legal framework for companion diagnostics in Article 2(7) and sets out the consultation requirement in Article 48. But the regulation's language is deliberately broad — it tells you that a consultation must happen without prescribing exactly how.

The EMA Q&A fills those gaps. It clarifies three things that matter most for teams navigating their first CDx consultation:

A companion diagnostic under IVDR is defined as a device "essential for the safe and effective use of a corresponding medicinal product." That word — essential — carries significant regulatory weight, because it means the CDx is not optional. Without it, the medicinal product cannot be prescribed safely. And that's precisely why the consultation procedure exists: to verify that the diagnostic is genuinely suitable for the therapeutic decision it enables.

When EMA Consultation Is Required

Why this matters: Getting the authority wrong doesn't just delay your submission — it can invalidate your entire conformity assessment. The decision tree below is the one your team should be using before any consultation is initiated.

The IVDR doesn't automatically route all companion diagnostic consultations through EMA. The determining factor is the regulatory status of the corresponding medicinal product — not the diagnostic device itself.

The nuance here is the word "exclusively." Some medicinal products can be authorised either centrally or nationally. If the product can go through a national route, the mandatory EMA requirement doesn't apply — even if the sponsor ultimately chooses the centralised procedure. The trigger is scope, not choice.

The 60-Day Consultation Procedure

Why this matters: Understanding each step — and especially the clock-stop mechanism — prevents the kind of timeline surprises that cascade through your entire development programme.

The consultation procedure for companion diagnostics is shorter than the ancillary substance procedure (60 days vs 210 days), but it carries its own complexities — particularly around who prepares what, and what triggers an extension.

The applicant for the consultation is the Notified Body — not the device manufacturer. This is a critical distinction because it means the Notified Body controls the submission timeline and manages the regulatory relationship with EMA. The manufacturer provides the technical content, but the formal interaction runs through the NB.

That said, EMA's procedural guidance recommends close collaboration between the NB and manufacturer throughout. The consultation dossier should reflect both the NB's conformity assessment perspective and the manufacturer's technical expertise. Misalignment between the two is one of the most common reasons for questions during the assessment period.

What You Need to Submit

Why this matters: The consultation is based entirely on two documents — the SSP and IFU. If these don't contain sufficient performance data, EMA will issue questions that can double your timeline.

Unlike the ancillary substance consultation, which requires a comprehensive dossier covering quality, safety, and usefulness, the CDx consultation focuses specifically on suitability — whether the diagnostic is fit for the therapeutic decision it supports.

The EMA guidance specifically calls out that "a sufficient level of information regarding the analytical and clinical performance" must appear in both the SSP and IFU. This isn't a vague request — it means EMA expects to see actual performance data, not just references to studies that exist elsewhere.

Follow-Up Consultations and Changes

Why this matters: Your CDx will evolve — new biomarkers, updated cut-off values, expanded indications for the corresponding drug. Each change triggers a regulatory decision that can either be a 30-day follow-up or a full 60-day re-consultation.

Once an initial consultation opinion is issued, ongoing obligations don't end. Article 48 of the IVDR requires that when changes are made to a CDx that affect its performance, intended use, or suitability in relation to the medicinal product, the manufacturer must inform the Notified Body. The NB then determines whether a follow-up consultation is needed.

The practical implication is significant: a change to cut-off values for an existing biomarker might qualify as a 30-day follow-up, while adding an entirely new biomarker to the CDx panel would likely trigger a new initial consultation. The Notified Body makes this determination, but EMA's procedural guidance recommends advance notice — ideally at least one month before the planned follow-up submission — so that appropriate planning can occur on both sides.

There's also a post-consultation information flow obligation. If EMA obtains new information about the corresponding medicinal product that could affect the CDx's suitability assessment, EMA is obligated to advise the Notified Body. The NB must then consider this information when reviewing the conformity assessment — potentially triggering a new consultation even without changes to the CDx itself.

Timelines and Fees That Nobody Maps

Why this matters: Your project plan needs real numbers — not regulatory aspirations. The table below shows what to actually budget for.

Fees for CDx consultations follow the same framework established in Council Regulation (EC) No 297/95. The fee is charged to the device manufacturer, not the Notified Body, and SME reductions are available for qualifying manufacturers registered with EMA's SME office.

What most teams underestimate isn't the fee itself — it's the indirect cost. The consultation period happens while your medicinal product development is ongoing, and misalignment between the CDx consultation timeline and the drug's regulatory milestones can create a dependency bottleneck. If your CDx opinion isn't ready when the MAA assessors need it, the entire submission can stall.