AbbVie is securing its place in an emerging gastrointestinal disease drug field, paying China-based FutureGen Biopharmaceutical $150 million in immediate and near-term fees for rights to an antibody drug targeting TL1A, a molecule linked to heightened immune responses in inflammatory bowel disease.

The Illinois-based drugmaker is following rivals like Merck, Roche, Teva and Sanofi, which have piled billions of dollars into acquisitions to gain ownership of TL1A-targeting drugs.

Per terms of the deal announced Thursday, AbbVie will gain global rights to the drug, called FG-M701, and will be responsible for its development, manufacturing and commercialization. FutureGen could receive up to $1.56 billion in additional fees based on hitting development, regulatory and sales milestones.

With FG-M701, AbbVie has a potential successor to its blockbuster antibody drugs Humira and Skyrizi, which are both used in the inflammatory bowel disorders Crohn’s disease and ulcerative colitis. Humira’s main patents have expired and are subject to biosimilar competition. Skyrizi will likely be secure through 2033, however.

FG-M701 hasn’t yet been tested in the clinic, putting it years from market. But, if all goes well, the drug could be in a good position to launch as Skyrizi nears the end of its market exclusivity.

Despite drugs like Skyrizi and Humira, and others like Johnson & Johnson’s Stelara, many people with Crohn’s and ulcerative colitis don’t respond or achieve lasting remission. In response, drugmakers have sought out new mechanisms of action such as TL1A.

AbbVie’s rivals have paid significantly more in some cases to acquire TL1A drugs. Merck & Co. paid nearly $11 billion to buy Prometheus Biosciences for an experimental drug that’s completed Phase 2 testing, while Roche paid $7.1 billion to buy a Roivant-Pfizer joint venture with a drug at a similar stage of development. Sanofi has also paid Teva $500 million to collaborate on a TL1A medicine.

At least one small biotech has also gotten in the game: Spyre Therapeutics raised $180 million to advance a TL1A agent and another candidate into human testing this year.