Protagonist Therapeutics has dosed the first patient in a Phase II study evaluating novel hepcidin mimetic PTG-300 for the treatment of patients with polycythemia vera (PV).

PV is a myeloproliferative disorder characterised by the overproduction of red blood cells.

The Phase II clinical proof-of-concept study is expected to enrol about 30 patients. It will monitor the safety profile and obtain preliminary evidence of efficacy in patients requiring phlebotomy.

It comprises a 16-week open-label dose-escalation stage every four weeks from 10mg to 80mg and a 12-week maintenance period at doses that generate desired hematocrit levels followed by a randomised and blinded withdrawal stage for 12 weeks.

The PTG-300 study also has an open-label extension for up to one year to monitor the drug’s long-term safety and benefits.

The study’s endpoints include the measurement of blood parameters, including hematocrit and haemoglobin levels, reductions or delay in phlebotomy requirements, and improvements in quality-of-life symptoms.

Protagonist Therapeutics president and CEO Dinesh Patel said: “In addition to our ongoing study of PTG-300 in patients with beta-thalassemia, we are excited to expand its clinical development with the initiation of this proof-of-concept study in polycythemia vera.

“An important aspect of the mechanism of action of the hepcidin mimetic PTG-300 is to reduce iron availability, which is required to support the excessive erythropoiesis which occurs in PV, thereby potentially enabling PTG-300 to manage this excessive erythropoiesis and ultimately reduce the phlebotomy burden in these patients.”

The injectable hepcidin mimetic PTG-300 has secured Orphan Drug designation in the US and EU.

The US Food and Drug Administration also granted fast-track designation for development in the potential treatment of beta-thalassemia.

In January this year, Protagonist dosed the first patient in a Phase II trial of PTG-300 for the treatment of patients with beta-thalassemia.