Adds details on deal in paragraph 5

April 22 (Reuters) - Regeneron Pharmaceuticals REGN.O said on Tuesday it has signed a deal worth more than $3 billion with contract drug developer Fujifilm Diosynth, potentially doubling its U.S. manufacturing capacity and bringing its total investments in the country to over $7 billion.

Major U.S. drugmakers, including Eli Lilly LLY.N and Johnson & Johnson JNJ.N, have recently announced additional investments in their U.S. production as they prepare to deal with potential drug import duties from President Donald Trump's administration.

Last week, the U.S. opened a national security investigation into pharmaceutical companies to show why the country needs tariffs to boost domestic manufacturing. Rates and timing remain uncertain, but the industry has been lobbying for phased-in tariffs.

Under the terms of the deal, Tokyo-based Fujifilm Diosynth's facility in Holly Springs, North Carolina will manufacture and supply drug products for Regeneron's biologic medicines for a span of 10 years. The facility is expected to be operational later this year.

Regeneron is also expanding its Tarrytown, New York-based facility and building a separate facility in the state to expand capacity to fill injection pens - a process known as fill-finish.

Its ongoing and planned investments in New York and North Carolina are expected to exceed $7 billion, Regeneron said, adding that it has added more than 7,000 jobs in the United States over the last five years.

(Reporting by Mariam Sunny in Bengaluru; Editing by Shreya Biswas and Shinjini Ganguli)

((Mariam.ESunny@thomsonreuters.com;))