(T1530-03-20) Vial Containment Systems for Gene Therapy Drug Products

Purpose: Viral vector based gene therapy drug products typically are stored and distributed at ultra-low temperature (a freezer at ca. -80^oC or a container with dry ice at ca. -78^oC). There are several requirements of the vial containment system (i.e., vial, elastomer stopper, seal) for these drug products. It must maintain container closure integrity (CCI) performance through fill/finish operations, storage/distribution, and thaw. Also, it must have no adverse interaction with drug product. Finally, it must provide adequate recovery and functionality of vector, whether adeno-associated virus, adenovirus, or lentivirus. These requirements are more challenging than those for a vial containment system for a drug product stored and distributed at room or refrigerated temperature. Understanding performance against these requirements is essential for a manufacturer to decide if a vial containment system is potentially suitable. The purpose of the present research was a multi-year study to characterize the performance of vial containment systems comprising cyclic olefin polymer (COP) vials, bromobutyl elastomer stoppers [with ethene tetrafluoroethene (ETFE) laminate film facing drug product] and aluminum flip off seals Characterization was based both on fundamental materials properties and experimental measurements of CCI performance at ultra-low temperature, reduced potential interaction with drug product, and retention of virus viability. Comparators were vial containment systems comprising glass and polypropylene.

Methods: CCI performance over time at -80^oC and dry ice storage was evaluated by laser-based headspace analysis with both oxygen and carbon dioxide. Potential interaction with drug product was evaluated by: (a) model proteins exposure to glass and polymer systems and measurement of both particle formation and protein loss, and (b) gas chromatography headspace analysis of stoppers with and without ETFE laminate and measurement of levels of permeated compounds. Virus recovery after freeze-thaw was evaluated by optical density technique (260 nm light) and virus functionality was evaluated by flow cytometry (green fluorescent protein).

Results: CCI performance evaluation was made of systems comprising 2 ml COP vials, 13 mm stoppers, and 13 mm seals that were stored at -80^oC for up to two years. Example data are shown in the Figure. No ingress of oxygen was observed over 1 year and only a small amount (5%) was observed over 2 years (likely through permeation of COP vial). Even though some oxygen ingress was observed, there was no system breach; if there was, 21% oxygen would have been observed. In the case of storage on dry ice for 7 days, after 30 minutes at room temperature no ingress of CO₂ was observed, but after 3 days CO₂ ingress at 2.5% was observed. Ingress can be reduced substantially with a poly(ethylene terephthalate)-based secondary container. Potential interaction with drug product was evaluated in two ways. The first was by exposure of model proteins to COP vials, glass vials, and various stoppers under agitated conditions and measuring the levels of particles formed and protein loss – both indicators of unwanted interaction that may be extrapolated to virus capsids. Example data are shown in Table 1 – stoppers with ETFE gave enhanced performance as indicated by a lower level of particle formation and better protein recovery. Similar data were obtained comparing COP vials to glass vials and will be presented also. Virus recovery and functionality were evaluated after storage at -80^oC and thaw for selected adeno-associated viruses, adenoviruses, and lentiviruses. Example data for the adenovirus Ad5.F35-CMV-eGFP are shown in Table 2. The system comprising 2 ml COP vials, 13 mm stoppers, and 13 mm seals performed equivalent, within error limits, to the standard polypropylene screwcap vial system.

Conclusion: All factors considered (CCI performance, reducing risk of potential interaction, virus viability, materials of construction), vial containment systems comprising COP vials, bromobutyl elastomer stoppers with ETFE laminates, and aluminum flip-off seals, offer very good performance for the ultra-low temperature storage of virus-based gene therapy drug products versus systems comprising glass or polypropylene.

References: R. Singh, L. Waxman, L. Fang, C. Zhao. An Investigation to Examine the Effect of the Elastomeric Surface Treatment on Protein Stability. PDA Journal of Pharmaceutical Science and Technology, 75, 230-244 (2021)
R. Singh and L. Waxman. Effect of Container Surface on Adsorption and Aggregation of Protein Therapeutics. 2018 PDA Universe of Pre-Filled Syringes and Injection Devices, Orlando, FL (August 8, 2018)

Figure 1. CCI Performance after Storage at -80oC for One and Two Years

Table 1. Particle Formation and Protein Loss upon Exposure of Select Protein to Elastomer Stoppers with and without ETFE Laminate Film

Table 2. Vitality of Select Adenovirus after Storage at -80oC in COP and Polypropylene Containment Systems