A primary concern for any operations or quality assurance manager who oversees a commercial or clinical cell manufacturing process is to tightly control the reagents used to perform critical process parameter steps. Clostridial histolyticum collagenases demand this oversight since the quality and consistency of these enzymes directly impact the reproducibility of cell isolation/recovery methods. However, with only a few suppliers of GMP Grade purified C. histolyticum collagenases, the risk of backorders is a concern. The focus of this post is to review the steps VitaCyte takes to ensure that collagenase backorders are improbable.
VitaCyte’s staff has the industry’s broadest expertise in manufacturing C. histolyticum collagenases and associated proteases. Bob McCarthy and Francis Dwulet, co-founders of VitaCyte, were key project team members in the development of the first purified collagenase-protease enzyme mixture at Boehringer Mannheim Biochemicals in 1994. Liberase™ HI Purified Enzyme Blend resolved a significant problem in realizing the promise of human islet transplantation, enabling the recovery of a sufficient number of islets for subsequent transplantation. Liberase HI quickly became the gold standard product for human islet isolation and contributed to the success of the Edmonton Protocol, the first demonstration that human islet transplantation could successfully treat adult type 1 diabetic patients with hypoglycemic unawareness. A recent review of the initial development of Liberase HI and subsequent enzyme improvements summarized insights into enzyme-mediated cell isolation.1 VitaCyte’s Collagenase HA and Roche’s purified collagenase found in the Liberase products are very similar, each containing a 60:40 class I:class II mixture of intact collagenase.
VitaCyte’s Collagenase HA product is unlikely to encounter backorders for several reasons.
- VitaCyte tightly controls the entire manufacture of collagenase, from raw material, through purified intermediates, to the final products.
- The inventory levels for each component are carefully monitored based on sales demand.
- The trigger for generating a new lot of final product occurs when the existing inventory approaches a three-month inventory level.
- The triggers for purified intermediates and raw materials are 6 and 9 months inventory levels, respectively. If sales increase, these levels are adjusted to maintain the appropriate inventory level.
Manufacture of a new Collagenase HA lot requires thawing the frozen purified class I and class II collagenase intermediates (each stored separately), mixing the product in a 60:40 class I:class II ratio, and sterilizing the mixture by passage through a sterile 0.22 µM filter in a biosafety cabinet. The sterile product is assayed for collagenase activity, then dispensed by an aseptic fill into sterile serum bottles in a biosafety hood, frozen, then lyophilized. Multiple bottles from the new lot of product are analyzed to ensure it meets specifications. A small number of retention samples is set aside for future analyses if appropriate.
Collagenase is stable for at least four years when stored at or below -20ºC. This claim is based on real time stability analysis of selected retention samples stored for at least four years at -20ºC. These analyses showed that the product met final product specifications. The long shelf life ensures use of these products before expiration.