Study stopped prior to subject administered first dose, due to COVID-19

The primary purpose of this study is to determine the safety and tolerability of SLN124 for the treatment of non-transfusion-dependent (NTD) β-thalassaemia and low risk myelodysplastic syndrome.

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