PTGX ▼ -2.3% - Protagonist Therapeutics, Inc. $PTGX - Protagonist Therapeutics Announces U.S. FDA Approval of Hepcidin Mimetic Peptide MIMRYLO(TM) (rusfertide) for Polycythemia Vera Protagonist Therapeutics shares fell 2.3% despite the company announcing FDA approval of its hepcidin mimetic peptide MIMRYLO for polycythemia vera treatment. The decline is notable given the positive regulatory milestone, suggesting investors may have been expecting the approval or are reacting to other factors not captured in the headline alone. 28-AUG-2026 08:30 PM ET