Tofacitinib 5 mg and 10 mg may have been associated with a modest decrease in hemoglobin (Hb) baseline during the third month of the trial (-0.2 and -0.3 g/dL, respectively) [13]. According to more recent data from RA populations, upadacitinib 30 mg may also cause a transient decrease in Hb and neutrophil counts, though these findings have not yet been confirmed in PsA [38]. The gene discussed is GSTM1; the disease is rheumatoid arthritis.