The new investment at the Limerick Industrial Operations and Product Supply (IOPS) campus will create an additional 300 new jobs.
Regeneron has taken its total investment for the facility to $750m and will grow its employee count to 800 through the expansion project.
According to Regeneron, the additional investment will help in construction of various manufacturing suites to the 400,000ft2 production facility in Limerick which produces large scale bulk biologics.
The expansion project is expected to allow the company to address demand for its life-transforming medicines for patients having serious diseases.
Regeneron IOPS executive vice president and general manager Dan Van Plew said: “Gut feel is a large portion of any site selection. When we picked Limerick years ago, we simply felt good about the community, universities and people.
“A few years and a lot of experience later, I can now confidently say I know Limerick is a place where you can build and thrive as a biotech. We are proud of what has happened here and the vast majority of this work has been completed by people who come from Munster.”
IOPS, which had become operational in 2015, handles the production, packaging, labelling and supply of Regeneron medicines.
It manufactures a wide range of biopharmaceuticals for patients across the world. These include therapeutic proteins that have been approved for marketing by regional or national regulatory agencies and those taking part in clinical studies.
Regeneron’s expansion project at Limerick is backed by the Irish government through IDA Ireland.
Ireland Taoiseach Leo Varadkar TD said: “Regeneron’s decision to expand so significantly is testament to the talent pool and attractive business environment available to companies in Ireland.
“This planned further expansion by Regeneron in Limerick is a significant contribution to the rejuvenation of the region.”