Milk Thistle Falls Short in JAMA Liver Disease Study

CHAPEL HILL, NCSilymarin extracted from milk thistle (Silybum marianum) failed to improve liver health in hepatitis C patients who previously had been unsuccessfully treated with interferon therapy, according to the results of a multicenter trial reported in the July 18 issue of JAMA (308(3):274-282). The researchers were all investigators with the Silymarin in NASH and C Hepatitis (SyNCH) Study Group.

The researchers used a multicenter, double-blind, placebo controlled design involving 154 patients with chronic hepatitis C virus (HPV) infection, who had serum alanine aminotransferase (ALT) levels of 65 U/L or greater and were previously unsuccessfully treated with interferon-based therapy. In the study, conducted at four medical centersUniversity of North Carolina, Chapel Hill;  Beth Israel Deaconess Medical Center, Boston; and University of Pennsylvania and Thomas Jefferson University, both in Philadelphiapatients were randomly assigned to receive either 420 mg silymarin, 700 mg silymarin or a placebo three times per day for 24weeks. Researchers measured serum levels of ALT, a test to determine liver disease, and charted changes in ALT levels, HCV RNA levels and quality-of-life measures. They looked for ALT levels lower than 45 U/L, which indicates normal liver health.

Results showed after 24 weeks, only two patients in each treatment group had ALT levels  in the normal range. There was no significant difference between the groups in terms of mean decline in serum ALT activity at 24 weeks. Similarly, there were no differences in HCV RNA levels or quality of life measures between the groups. On a positive note for silymarin, the extract was well-tolerated, with no difference in adverse events between any of the three treatments.

The researchers concluded, "Oral silymarin, used at higher than customary doses, did not significantly alter biochemical or virological markers of disease activity in patients with chronic HCV infection who had prior treatment with IFN-based regimens. Silymarin did not provide greater benefit than placebo for patients with treatment-resistant chronic HCV infection."