Preclinical development of vaccine candidates is an important link between the discovery and manufacture of vaccines for use in human clinical trials. Here, an exploratory clinical study utilizing multiple gp120 envelope proteins as vaccine antigens was pursued, which required a harmonized platform development approach for timely and efficient manufacture of the combined HIV vaccine product. Development of cell lines, processes, and analytical methods was initiated with a transmitted founder envelope protein (CH505TF), then applied to produce three subsequent gp120 Env (envelope) variants. Cell lines were developed using the commercially available Freedom CHO DG44 kit (Life Technologies). The fed-batch cell culture production process was based on a commercially-available medium with harmonized process parameters across the variants. A platform purification process was developed utilizing a mixed mode chromatography capture step, with ceramic hydroxyapatite and ion exchange polishing steps. A suite of analytical methods was developed to establish and monitor the Quality Target Profile (QTP), release and long-term stability testing of the vaccine products. The platform development strategy was successfully implemented to produce four gp120 envelope protein variants. In some cases, minor changes to the platform were required to optimize for a particular variant; however, baseline conditions for the processes (cell line type, media & feed system, chromatography resins, and analytical approaches) remained constant, leading to successful transfer and manufacture of all four proteins in a cGMP facility. This body of work demonstrates successful pursuit of a platform development approach to manufacture important vaccine candidates and can be used as a model for other vaccine glycoproteins, such as HIV gp140 trimers or other viral glycoproteins with global health implications. Clinical trial identifier. NCT03220724, NCT03856996.
Bispecific biotherapeutics offer potent and highly specific treatment options in oncology and immuno-oncology. However, many bispecific formats are prone to high levels of aggregation and instability, leading to prolonged development timelines, inefficient manufacturing, and high costs. The novel class of Mabcalin™ molecules consist of Anticalin® proteins fused to an IgG and are currently being evaluated in pre-clinical and clinical studies. Here, we describe a robust high-yield manufacturing platform for these therapeutic fusion proteins providing data up to commercially relevant scales. A platform upstream process was established for one of the Mabcalin bispecifics and then applied to other clinically relevant drug candidates with different IgG target specificities. Process performance was compared in 3 L bioreactors and production was scaled-up to up to 1000 L for confirmation. The Mabcalin proteins' structural and biophysical similarities enabled a downstream platform approach consisting of initial protein A capture, viral inactivation, mixed-mode anion exchange polishing, second polishing by cation exchange or hydrophobic interaction chromatography, viral filtration, buffer exchange and concentration by ultrafiltration/diafiltration. All three processes met their target specifications and achieved comparable clearance of impurities and product yields across scales. The described platform approach provides a fast and economic path to process confirmation and is well comparable to classical monoclonal antibody approaches in terms of costs and time to clinic.