All-trans retinoic acid for treatment of chronic hepatitis C

Background/Aims: In vitro studies in the subgenomic hepatitis C virus (HCV) replicon system have identified all-trans retinoic acid (ATRA) as a potential therapeutic against hepatitis C. Thus, the antiviral potential of this drug should be assessed in vivo. Methods: Twenty highly treatment experienced serotype 1 patients with non-response to conventional or pegylated interferon-alpha (Peg-/IFN-alpha) and ribavirin were randomly assigned to 12 weeks of monotherapy with ATRA (group A) or a combination of ATRA and PegIFN-alpha 2a ( group B). HCV RNA was assessed by bDNA assay and if negative by highly sensitive polymerase chain reaction. Results: During treatment, five of 10 patients in group A had a drop of viraemia > 1log, while in group B after 8 weeks five of 10 dropped > 2log, and three of 10 cleared HCV RNA from serum. Viraemia relapsed after treatment cessation. ATRA was rather well tolerated, with transient headache, dry skin and mucosa representing the most common side effects. Conclusions: The viral load reduction under ATRA monotherapy, although limited and transient, supports the antiviral activity of ATRA. However, the rapid loss of HCV RNA in three of 10 previous non-responders under ATRA and PegIFN-alpha 2a treatment demonstrates a strong additive or synergistic ATRA effect and calls for a controlled trial to assess the therapeutic potential of this drug.