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# Protagonist Therapeutics Hold Lifted on Trials
- URL: https://www.fdaweb.com/protagonist-therapeutics-hold-lifted-on-trials/
- Published: 2021-10-11T12:00:00.000Z
- Updated: 2026-09-14T17:18:38.000Z
- Author: David McFarland
- Tags: Drugs, #legacy-id-D5150334

FDA has lifted a Protagonist Therapeutics clinical hold on the company's rusfertide clinical studies. The hold followed notification to FDA about a recent non-clinical finding in a 26-week rasH2 transgenic mouse model study, according to the company. “The rasH2 model is designed to detect signals related to tumorigenicity, and benign and malignant subcutaneous skin tumors were observed in this study,” it says. Affected trials for the injectable hepcidin mimetic include a Phase 2 proof-of-concept clinical trial for polycythemia vera (PV), a Phase 2 study in PV subjects with high hematocrit levels, and a Phase 2 study for hereditary hemochromatosis.

Protagonist says it provided all requested information as the basis for a complete response and subsequent clinical hold removal of the clinical hold. “In particular, the company provided the requested individual patient clinical safety reports, updated the investigator brochure and patient informed consent forms, performed a comprehensive review of the most recent safety database, and included new safety and stopping rules in the study protocols,” it explains.