GSK has invested $800m into its drug substance and product manufacturing capabilities at the company's Pennsylvanian site.
The investment will create more than 200 new jobs, and is the largest manufacturing investment that GSK has made to date.
At the Marietta site, GSK will be able to manufacture sterile liquid vaccines and medicines, while also having the ability to manufacture medicines for clinical trials with its R&D pilot plant.
GSK will also establish a new vaccines drug substance facility at the site.
Through this expansion, the Marietta facility will be doubled both in size and capacity — allowing the company to better serve the pharmaceutical market in the US and beyond.
The pharma giant has also taken sustainability into account with this build, as the site will have solar panels and electric heat generation.
Continuous process optimisation, robotics, predictive maintenance and digital scheduling will also be incorporated to ensure the optimal functioning of the facility.
Construction should begin at the end of 2024, with the drug substance facility estimated to be operational by the end of 2027 and the drug product facility following by the end of 2028.
GSK's President of Global Supply Chain, Regis Simard, said: "This landmark investment will establish Marietta as an innovation and manufacturing hub capable of delivering next generation medicines and vaccines to people around the world."
"We’re grateful for the support of local and state officials, who made this project possible, and we are excited to expand upon the important work already underway at the Marietta site.