Protagonist Therapeutics (PTGX) said Monday the US Food and Drug Administration has granted its drug candidate rusfertide Breakthrough Therapy Designation for the treatment of erythrocytosis in patients with polycythemia vera, a blood disease.

The company said the designation, intended to expedite development and review of promising treatments, was based on results from a phase 3 trial. The designation also sets the drug candidate up for priority New Drug Application review, the company said.

Rusfertide is being co-developed with Takeda Pharmaceuticals (TAK), though Protagonist is primarily responsible for its development through its NDA filing.

Protagonist said the company intends to submit an NDA for rusfertide in Q4.