Recent publications have highlighted the greater understanding of the mechanisms of BTH due to inadequate complement inhibition compared with complement activating events and the different treatment approaches required for these different mechanisms.[7, 8] A C3 inhibitor, pegcetacoplan, has shown promising results in a phase 3 open‐label, controlled trial in patients with ongoing anaemia (Hb < 10.5 g/L) despite eculizumab (PEGASUS).[9] The primary endpoint was change in Hb from baseline to week 16. This evidence concerns the gene GSTM1 and anemia.