Comparison of 2 emulsion-based digital PCR systems: ddPCR from BioRad vs. dPCR from Stilla, for reliable determination of AAV genome titre

Adeno-associated viruses (AAV) have emerged as a leading vector for gene delivery for treating various diseases due to its safety profile and efficient transduction of numerous target tissues. AAV, like other viral vectors, are complex molecules leading to challenges in their characterisation. OXB is advancing its AAV process development and manufacturing platforms and is becoming an industry leader in AAV manufacturing and control of several serotypes (currently AAV2/5/6/8 and 9). For its part, as a leading actor in cutting-edge analytical services dedicated to innovative medicinal products, Quality Assistance is committed to develop a reliable titration method to assess the safety and efficacy of AAV-based gene therapies from clinical or preclinical stages to drug product QC.

Whether for monitoring the entire manufacturing process (enrichment of the full / empty ratio of AAV particles) or ensuring accurate dosing of the drug product, an exact viral titration of the vector genome copies is critical for rAAVs-based products. Historically, qPCR has been a fast, accurate, and inexpensive method for quantifying viral vectors. Recently, digital PCR has gained popularity, particularly given that it allows for absolute quantification without the need for a reference standard (thus avoiding standard curve bias or the lack of existing standards) and because it offers better performance in terms of accuracy and precision. It is now considered an interesting alternative to the classical qPCR method.

This application note describes how different digital PCR equipment – here two major actors of the emulsion-based digital PCR, the BioRad QX200 and Stilla Naica platforms – can provide a reliable AAV genome titre while evaluating the difference they encompass.

About OXB

OXB is a quality and innovation-led CDMO in cell and gene therapy with over 25 years of experience in manufacturing. They offer end-to-end capabilities, from plasmid design and optimisation to clinical and commercial GMP manufacturing, accompanied by robust control systems, analytical methods and deep regulatory knowledge. They have an expertise, among others, across lentivirus, AAV, and adenoviral vectors and have developed our LentiVector® and inAAVate™ platforms.