FDA slaps hold on Protagonist trial for lead candidate

Sept. 17, 2021

Protagonist Therapeutics said it received verbal communication from the U.S. FDA that the company's clinical studies for its lead investigational product candidate for blood cancer, rusfertide, have been placed on a clinical hold.

The clinical hold follows the California-based biotech's notification to the FDA of a recent non-clinical finding in a 26-week rasH2 transgenic mouse model study. Both benign and malignant subcutaneous skin tumors were observed in this study.

Rusfertide (PTG-300) is an injectable hepcidin mimetic that was currently in a Phase 2 study for the treatment of polycythemia vera, a rare type of blood cancer.

The company is collaborating with the FDA and says it will be ready to make any necessary revisions to clinical trial papers as well as identify future steps in collaboration with the agency. All rusfertide dosing in active clinical trials will be halted, and study investigators have been notified to assist with patient communication.

Read the press release