Recently, there were reported that some factors associated with P-CAB non-responder (non-improvement of symptoms) in the patients with PPI-refractory GERD such as sleep disturbances, co-existing functional dyspepsia and alcohol abstinence.(37) However, there was not reported that factors of P-CAB non-responder (non-suppression of gastric acid) other than CYP3A4. Here, CYP3A4 is linked to gastroesophageal reflux disease.