Protagonist Therapeutics, Inc. announced that the U.S. Food and Drug Administration (FDA) has removed the full clinical hold on the Company's rusfertide clinical studies, announced on September 17, 2021. Per the FDA, dosing in all clinical studies of rusfertide may be resumed. The company provided the FDA with all requested information as the basis for a Complete Response and subsequent 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. The company is working closely with study investigators and clinical trial sites to resume dosing of patients in ongoing clinical trials with rusfertide after patients have been reconsented. The clinical hold was initially triggered by a recent non-clinical finding in a 26-week rasH2 transgenic mouse model indicating benign and malignant subcutaneous skin tumors. The rasH2 signal also prompted a re-examination of the four cases of cancer observed across all rusfertide clinical trials involving over 160 patients, and a comprehensive review of the safety database, including cases of suspected unexpected serious adverse reactions (SUSAR). No additional cancer cases, and no other unexpected safety signals, surfaced in this process.