Repression of BA synthesis and increased detoxification of BA by fibrates were confirmed in early-stage PBC patients measuring reduction of 7α-hydroxy-4-cholesten-3-one (C4), a marker of BA synthesis, and an increase of 4β-hydroxycholesterol, a marker of CYP3A4/5 activity after bezafibrate and UDCA combination therapy in comparison to UDCA monotherapy.184. The gene discussed is CYP3A4; the disease is primary biliary cholangitis.