AbbVie Inc. and Principia Biopharma Inc. mutually agreed to end a collaboration for the development of potential drugs known as oral immunoproteasome inhibitors.

Under the 2017 agreement, the companies were partnering to conduct research and pre-clinical studies of the potential treatments for autoimmune and inflammatory disorders. AbbVie was meant to initiate clinical development and commercialize the compounds discovered from the partnership.

South San Francisco, Calif.-based Principia has reacquired the rights to the program, with the termination effective in March.