SP-420 in Subjects With Transfusion-dependent Beta-Thalassemia or Other Rare Anemias

Inclusion Criteria: * At least 18 years old * Iron-overload secondary to β-thalassemia (homozygote or compound heterozygote) or other rare anemias (e.g., aplastic anemia, pure red-cell dysplasia ) requiring chronic RBC transfusions and iron chelation therapy * On a stable dose of iron chelation for at least 4 weeks prior to screening visit * Weight ≥35 kg at screening * Willing to discontinue current iron chelation therapy 7 days (± 3 days) prior to the first dose of SP-420 and for the duration of the current study * LIC ≥5 and ≤25 mg/g dry weight on the R2-MRI obtained within 2 weeks prior to the baseline visit * Cardiac T2\* score \> 12 msec obtained on the MRI obtained within 2 weeks prior to the baseline visit Exclusion Criteria: * Pregnant or breast-feeding * Current malignancy with the exceptions of localized basal cell or squamous cell skin cancer or localized prostate cancer or is receiving immunotherapy, chemotherapy or radiation therapy for a malignancy * Current myelodysplastic syndrome * Alanine aminotransferase (ALT) \>4 times the upper limit of normal, decompensated cirrhosis, or ascites at screening * Past history of clinically significant kidney disease (per the Principal Investigator) * Serum creatinine greater than the upper limit of normal during screening * Urine protein to creatinine ratio \> 0.5 mg/mg during screening * Ongoing symptoms of cardiac dysfunction or failure * Ongoing symptoms of neuropathy, including peripheral sensory neuropathy, peripheral motor neuropathy, or paresthesia at screening * Received another investigational drug within 30 days or investigational antibody within 90 days of Day 1 of the study * Other condition that, in the opinion of the PI, would interfere with the conduct of the study