Study in Beta-thalassaemia or Myelodysplastic Syndrome Patients to Investigate the Safety and Tolerability of SLN124

Inclusion Criteria: * Age ≥ 18yrs; BMI 18-35 kg/m2 * β-thalassaemia intermedia or compound heterozygous HbE/β-thalassaemia * Non-transfusion dependent: ≤ 5 units red cells in last 6 months and transfusion-free for ≥8 weeks * Hb between 5 \& 11 g/dL * Ferritin \> 250 µg/L and /or liver iron ≥ 3mg Fe/g dry weight and TSAT \>40% Exclusion Criteria: * Haemoglobin S/β-thalassaemia, homozygous β-0 thalassaemia or α thalassaemia * ALT/AST \> 1.5 x upper limit normal or cirrhosis * eGFR \< 60 mL/min/1.73m2 * Platelets \<100 or \> 1000 x 109/L * Untreated B12/folate deficiency * Iron chelation therapy unless stable for ≥8 weeks * Daily NSAID, therapeutic dose anticoagulant, ESA ≤12 weeks or stable dosing of hydroxyurea ≤ 6 months * Significant cardiac disease (MI in 6 months, NYHA class III-IV heart failure, long QT) * HIV or active hepatitis B/C or malignancy within 5 year