Ireland-based Allergan is buying US biotech Tobira Therapeutics in a deal potentially worth up to $1.7 billion, as well as Akarna Therapeutics in a deal worth at least $50 million, securing itself access to a batch of experimental therapies for nonalcoholic steatohepatitis (NASH).

As per the terms of the deal, the drugmaker will pay Tobira $28.35 per share in cash, as well as contingent value rights of up to $49.84 per share linked to certain development, regulatory and commercial milestones.

The acquisition expands Allergan's gastroenterology R&D offering with Cenicriviroc and Evogliptin, which the firm says are two differentiated, complementary development programmes for the treatment of the multi-factorial elements of NASH, including inflammation, metabolic syndromes and fibrosis.

Just hours after the deal was announced, Allergan revealed a second purchase; Akarna Therapeutics, a privately-held biopharma focused on developing novel small molecule therapeutics that target inflammatory and fibrotic diseases for an up-front payment of $50 million.

Akarna's lead drug, AKN-083, is a potentially best-in-class preclinical farnesoid X receptor agonist in development for the treatment of NASH, and is highly complementary to compounds in development by Tobira, the firm noted.

"With the increasing rates of diabetes, obesity and other metabolic conditions in the US and in developed nations globally, NASH is set to become one of the next epidemic-level chronic diseases we face as a society," said Allergan's chief executive and president, Brent Saunders, explaining the strategy behind the move.

"It is important that we invest in new treatments today so that healthcare systems, providers and patients have treatment options to face this challenge in the coming years."

It's been a busy year for Allergan; following the demise of its $160-billion merger with Pfizer, the group divested its US generics arm Anda to Teva for $500 million, and signed a $3.3-billion deal with Heptares for access to the UK-based group's portfolio of experimental neurological therapies.