MAT: to GMP or not to GMP? That's a question causing frequent confusion in the pharma industry.

Based on many industry discussions, it's clear there's a misunderstanding about when to apply Good Manufacturing Practices (GMP), especially for analytical methods like the Monocyte Activation Test (MAT).
The answer is simpler than you think. The regulatory status isn't determined by the activity itself, but by its PURPOSE.
Let's break down the MAT lifecycle:

BUILDING the Strategy (Managed by the PQS, but NOT GMP Certified)

These activities are foundational and scientific. Their purpose is to create and justify the control strategy, not to execute it on a commercial batch.

• Pyrogenicity Risk Analysis (ICH Q9): This is a strategic, cognitive activity. You are thinking and justifying why and how you will test, not actually testing a batch for release.
• MAT Method Development: This is pure R&D. It must be flexible and iterative. Applying rigid GMP rules here is a "conformity paradox" – you can't follow a fixed procedure when your goal is to create that procedure.
• MAT Method Validation (ICH Q2): This is a formal, one-time project. Its purpose is to prove and document that the method is "fit for purpose." It is a prerequisite to GMP use, much like qualifying a new piece of equipment (Annex 15). It generates a static report for your Marketing Authorisation (MA) file.

EXECUTING the Strategy (Absolutely a GMP Certified Activity)
This is where the switch flips. The purpose is no longer knowledge generation; it's routine execution for a batch decision.

• Routine MAT for Batch Release (EudraLex Ch 6): Here, you are strictly following the validated, MA-approved method on a specific commercial batch. The result directly informs the Qualified Person's (QP) decision to release or reject that product. This is the very definition of a GMP Quality Control test.

Why This Distinction Matters
Confusing these two phases means applying rigid, inflexible GMP controls to flexible R&D and validation processes. This stifles innovation, misallocates resources, and fundamentally misunderstands the logical framework of EudraLex and ICH guidelines.

• Development (R&D) informs GMP.
• Validation qualifies the method for GMP.?
• Routine Batch Control is GMP.?

A robust Pharmaceutical Quality System (PQS) oversees all of these activities, but it applies the right controls for the right purpose.
Do you see this "GMP vs. non-GMP" confusion in your organization? Let's discuss.