The presentation addresses the challenges associated with the small batch size required for gene therapy (and similar) products with specifics on considerations for solutions in overcoming those challenges related to filling and the container closure system. The presentation will include the challenges and how those challenges can be addressed through the use of glass vials and press fit caps. The testing methodology for container closure integrity testing of press fit caps (in place of traditional aluminum overseals) and manufacturing considerations required to ensure proper CCI will be addressed. The pros and cons of conversion to this style of closure versus traditional closures will be addressed. The important take-aways for this will be an understanding of how press fit caps address challenges for container closure of gene therapy products and how to assess a manufacturing system to determine if press fit caps are the right solution.