Beta Thalassemia Major Anemia

The goal of this clinical trial is to learn about SP-420 ability to remove iron from organs in subjects with transfusion-dependent β-thalassemia or transfusion-dependent low-risk myelodysplastic syndrome. The main questions it aims to answer are: * How efficient is SP-420 in cleaning iron from the liver? * How is the safety and tolerability of ascending doses of SP-420? Participants will: * Take medication three times weekly * Attend up to 20 site visits * Undergo MRI scans