Protagonist Therapeutics, Inc. expected to announced top-line data from its Phase 2 clinical trial evaluating its product candidate PN-943 for ulcerative colitis in the first half of the second quarter of 2022. The company has received a letter from United States Food and Drug Administration (the FDA") indicating the FDA's intent to rescind Breakthrough Therapy Designation for the Company's rusfertide product candidate in polycythemia vera. The Company has submitted a meeting request to the FDA, along with a briefing document articulating why the Company believes rusfertide continues to warrant Breakthrough Therapy Designation.

The FDA letter does not relate to the rusfertide Fast Track Designation, which remains active. Initiation of the company's rusfertide Phase 3 study in polycythemia vera is underway and no changes to the development plan or timeline are anticipated at this stage.