Protagonist announced preliminary results from the Phase 1 study of PTG-300 in normal healthy volunteers. PTG-300 is an injectable hepcidin mimetic peptide, discovered using the company's proprietary technology platform. Protagonist is developing PTG-300 as a potential treatment for patients with ineffective erythropoiesis in rare diseases such as beta-thalassemia and myelodysplastic syndromes (MDS).
The Phase 1 randomized, placebo-controlled single ascending- and repeat-dose study is being conducted to evaluate the safety, tolerability, pharmacokinetics and pharmacodynamics of PTG-300 in 62 normal healthy male volunteers. The study includes five cohorts of subjects in single ascending doses ranging from 1 mg to 40 mg, administered by subcutaneous injection.
Preliminary data following completion of these five single-dose cohorts indicates PTG-300's ability to achieve a dose-related reduction in serum iron, which persists beyond 72 hours at higher dose levels. This effect provides pharmacodynamic-based proof-of-concept for PTG-300 in healthy male volunteers. PTG-300 showed a dose-dependent increase in blood exposure, and was well tolerated, with no serious adverse events or dose-limiting toxicities. The most common adverse event was a transient and self-limited erythema (redness) at the injection site in some subjects at 10 mg or higher doses.
"Based on this encouraging data, we have amended the study to include two additional cohorts of an 80 mg single dose and a 40 mg dose for two weekly doses. These cohorts will further enhance the evaluation of the PK-PD effects and tolerability of PTG-300. We expect to report final top line results of the amended study in the fourth quarter of 2017," said Richard Shames, M.D., Chief Medical Officer at Protagonist.
PTG-300, an injectable hepcidin mimetic, is currently in clinical development for the potential treatment of beta-thalassemia and MDS, rare diseases characterized by chronic anemia and iron overload. Hepcidin is a peptide hormone that is the main regulatory hormone governing iron absorption, recycling and utilization by the body. Iron plays an essential role in various body functions, especially blood formation, but too much iron is toxic and causes organ damage over time. Such damage to the bone marrow, liver, and heart leads to the increased risks of ineffective erythropoiesis-induced anemia, liver disease, heart attack, heart failure, diabetes, and premature death. Abnormally low hepcidin levels, caused by genetic mutations or secondary pathology, can result in the body absorbing and storing more iron than is needed, leading to iron overload.