The firm is to invest £80m in two new pharma services and diagnostic facilities.
Mr Tennyson said: “It’s fantastic news that Almac is to create 550 highly-skilled jobs with this £80m investment.
“This will be a huge boost to the local area, is a sign of confidence in the wider Northern Ireland economy, and will no doubt make a significant contribution to improving health outcomes globally.
“Northern Ireland now has a relative competitive advantage via the dual market access provided for under the Windsor Framework. This is particularly evident and visible in highly regulated areas such as pharma.
“I wish the team at Almac every success with their expansion.”