- For participants with a suitable donor who meet eligibility criteria and are willing to proceed to HCT, if they have received chronic transfusion therapy for ≥ 1 year and have clinical evidence of iron overload by serum ferritin or MRI, an evaluation by liver biopsy is required. Histological examination of the liver must document the absence of cirrhosis, bridging fibrosis, and active hepatitis. The absence of bridging fibrosis will be determined using the histological grading and staging scale