4. A current diagnosis of iron deficiency (with or without anaemia); iron deficiency defined by ferritin <30 µg/L, or ferritin <50 µg/L with transferrin saturation (TSAT) <20%, as measured by the central laboratory at the Screening visit (subjects with or without anaemia may be enrolled providing Hb is ≥8.5 g/dL as measured at the Screening visit).