MAT Service Portfolio

A successful MAT implementation follows a structured, phased approach, moving from initial feasibility assessment to a fully validated method suitable for routine GMP use.

Phase I: Preliminary Testing (Feasibility) This initial phase is a critical risk-mitigation step designed to determine the fundamental suitability of the MAT for a specific product before committing to extensive development and validation. Rushing into validation without this screening is a common and costly error. The MAT relies on the response of living cells, and if the product itself is harmful to those cells, the test cannot work. This phase includes two key screens:

• Cytotoxicity Screen: The product is tested for any inherent toxicity to the monocytes. A cytotoxic product would kill the cells, preventing them from producing cytokines in response to a pyrogen and thereby leading to a false-negative result.   

• Interference Screen: The product is assessed for its potential to interfere with the assay's signaling or readout mechanisms. This is performed by spiking the product with known concentrations of endotoxin (a TLR4 ligand) and at least two different NEP controls (representing other TLR ligands, as required by EP 2.6.30). The percent recovery of these spikes is measured. A recovery outside the acceptable range of 50-200% indicates that the product matrix is either inhibiting or enhancing the cytokine response, which must be addressed during method development.   

Phase II: Method Development Once feasibility is confirmed, a robust and reliable method is developed. This involves:

• Method Selection: Based on the product's characteristics and regulatory requirements, one of the three compendial methods described in EP 2.6.30 is chosen. Method A (Quantitative Test) is the most common. Method C (Reference Lot Comparison Test) is particularly useful for complex biologics or vaccines where a well-characterized reference batch is available.   

• Optimization: The primary goal is to identify the optimal, non-interfering dilution of the product that allows for accurate pyrogen detection while minimizing any matrix effects identified in Phase I. Method robustness may also be assessed by intentionally varying critical parameters, such as incubation times, to ensure the method is reliable under routine laboratory conditions.   

Phase III: Product-Specific Validation The final phase is the formal validation of the developed method to document its fitness for purpose and to meet regulatory requirements.

• Regulatory Requirements: The validation requirements differ between major regulatory bodies. In Europe, because the MAT is a compendial method (EP 2.6.30), only a product-specific verification is required. This typically involves successfully executing the test for interfering factors on at least three independent production batches. For submission to the U.S. FDA, the MAT is considered an alternative method, and a full validation according to USP is generally expected. This is a more extensive exercise that formally assesses parameters such as Accuracy, Precision (Repeatability and Intermediate Precision), Specificity, Linearity, Range, and Robustness.   

• Validation Protocol and Report: The validation is executed under a formal, pre-approved protocol, and the results are compiled in a comprehensive validation report. This report serves as the official documentation to support the method's use in a GMP environment and is a key component of regulatory filings.