Validation and international regulatory experience for a mycoplasma touchdown PCR assay

Area of Science:

• Biotechnology and Pharmaceutical Manufacturing
• Microbiology and Molecular Diagnostics

Background:

• Mycoplasma contamination poses a significant risk to biopharmaceutical production, particularly in recombinant factor VIII (rFVIII) manufacturing.
• Current detection methods, primarily culture-based, can be time-consuming and may lack the sensitivity required for early contamination detection.

Purpose of the Study:

• To develop and validate a Polymerase Chain Reaction (PCR) assay for rapid and reliable detection of mycoplasma contamination in rFVIII production fermenters.
• To establish the assay as a suitable replacement for conventional culture-based methods in routine monitoring.

Main Methods:

• Development of a qualitative 'touchdown' (TD) PCR protocol utilizing primers specific to the 16S rRNA gene.
• A simplified nucleic acid extraction procedure was integrated into the workflow.
• Validation according to International Council for Harmonisation (ICH) guidelines, including limit of detection (LOD) and specificity studies.

Main Results:

• The PCR assay demonstrated a broad detection capacity for various mycoplasma species.
• Validated LOD was between 579 and 1715 mycoplasma genome copies/mL.
• Achieved 1000-10,000-fold greater specificity compared to Gram-positive bacteria and comparable sensitivity to culture methods down to 1 CFU/mL.

Conclusions:

• The developed PCR assay is a validated, sensitive, and specific tool for monitoring mycoplasma contamination in rFVIII fermenters.
• The method is suitable for replacing traditional culture-based assays in routine bioprocess monitoring.
• Regulatory approvals are progressing, with ongoing efforts to address comparative detection limits with culture-based methods.