Opportunities and challenges of real-time release testing in biopharmaceutical manufacturing.

Real-time release testing (RTRT) is defined as "the ability to evaluate and ensure the quality of in-process and/or final drug product based on process data, which typically includes a valid combination of measured material attributes and process controls" (ICH Q8[R2]). This article discusses sensors (process analytical technology, PAT) and control strategies that enable RTRT for the spectrum of critical quality attributes (CQAs) in biopharmaceutical manufacturing. Case studies from the small-molecule and biologic pharmaceutical industry are described to demonstrate how RTRT can be facilitated by integrated manufacturing and multivariable control strategies to ensure the quality of products. RTRT can enable increased assurance of product safety, efficacy, and quality-with improved productivity including faster release and potentially decreased costs-all of which improve the value to patients. To implement a complete RTRT solution, biologic drug manufacturers need to consider the special attributes of their industry, particularly sterility and the measurement of viral and microbial contamination. Continued advances in on-line and in-line sensor technologies are key for the biopharmaceutical manufacturing industry to achieve the potential of RTRT. Related article: http://onlinelibrary.wiley.com/doi/10.1002/bit.26378/full.

Proteomic profiling of a high-producing Chinese hamster ovary cell culture.

The productivity of mammalian cell culture expression systems is critically important to the production of biopharmaceuticals. In this study, a high-producing Chinese hamster ovary cell culture which was transfected with the apoptosis inhibitor Bcl-X(L) gene was compared to a low-producing control that was not transfected. Shotgun proteomics was used to compare the high and low-producing fed-batch cell cultures at different growth time points. The goals of this study were twofold; it would be of value to find a biomarker that could predict cell lines with higher growth efficiency and to gain mechanistic insights into the effects of the introduction of a foreign gene that is known to have growth regulating properties in human cells. A total of 392 proteins were identified in this study, and 32 of these proteins were determined to be differentially expressed. In the high-producing cell culture, several proteins related to protein metabolism were upregulated, such as eukaryotic translation initiation factor 3 and ribosome 40S. In addition, several intermediate filament proteins such as vimentin and annexin, as well as histone H1.2 and H2A, were downregulated in the high producer. The expression of these proteins may be indicative of cellular productivity. A growth inhibitor, galectin-1, was downregulated in the high producer, which may be linked to the expression of Bcl-X(L). The molecular chaperone BiP was upregulated significantly in the high producer and may indicate an unfolded protein response due to endoplasmic reticulum (ER) stress. Several proteins involved in regulation of the cell cycle such as RACK1 and GTPase Ran were found to be differentially expressed, which may be due to a differentially controlled cell cycle between low- and high-producing cell cultures.