AASLD 2011 (American Association for the Study of Liver Disease): da un trial randomizzato e controllato con placebo, presentato all'ultimo congresso dell'AASLD, emerge che non è vero che la silimarina, estratta dal cardo mariano, ha effetti benefici rilevabili sul decorso dell'epatite C.AASLD: Milk Thistle No Help in Chronic HCVBy Charles Bankhead, Staff Writer, MedPage Today
Published: November 14, 2011
SAN FRANCISCO -- A botanical agent used in the treatment of liver disorders had no detectable effect on hepatitis C virus (HCV) disease activity in comparison with placebo in patients with previously treated chronic disease, results of a randomized trial showed.
Patients treated for six months with either of two doses of silymarin had little change in levels of the liver enzyme alanine transaminase (ALT). About 4% of patients in each silymarin arm and in the placebo group met the primary endpoint of a decline in ALT to ≤45 IU or at least a 50% decline from baseline.
"Similarly, symptom scores and quality of life measures were unchanged during silymarin treatment," Michael W. Fried, MD, of the University of North Carolina in Chapel Hill, reported here at the American Association for the Study of Liver Diseases meeting.
The trial was perhaps the first to use a single, well-described silymarin preparation, and the doses employed in the study were five to seven times higher than customary doses, he added.
Silymarin is an extract of milk thistle and has long been used as a treatment for various types of liver disorders. A mixture of flavonolignans, silymarin has demonstrated anti-inflammatory and immunodulatory properties in vitro, as well as activity against the HCV core and virus-associated gene expression.
The substance has been evaluated in clinical trials as a therapeutic aid for cirrhosis, alcoholic liver disease, and viral hepatitis. However, the results have been inconsistent.
"Previous studies have been confounded by a lack of well-defined efficacy endpoints, inclusion of heterogeneous populations of patients with liver disease, and use of nonstandardized silymarin preparations," said Fried.
To address some of the shortcomings of previous clinical studies, the investigators designed a trial to evaluate silymarin as a potential aid in the treatment of chronic HCV that had not responded to interferon-based therapy.
All of the 154 patients enrolled at four centers in the U.S. had a history of treatment with interferon-based therapy and had not achieved a sustained virologic response. The patients had quantifiable HCV RNA and a serum ALT ≥65 IU.
The silymarin preparation used for the trial is produced in the Netherlands under the brand name Legalon 140 and is approved as a prescription drug in some European and Asian countries. The customary dose is 140 mg three times a day.
Eligible patients were randomized to one of two doses of silymarin (420 or 700 mg) or placebo. Patients in the high-dose silymarin arm took five capsules of the botanical agent three times daily. Patients randomized to the standard dose took three silymarin capsules and two placebo capsules three times each day, and patients in the placebo arm took five matching capsules three times daily.
The high-dose arm was based on results from a phase I dose-finding trial "in order to provide the highest likelihood of finding a therapeutic benefit," said Fried.
The primary endpoint, measured after 24 weeks, was a decline in serum ALT to ≤45 IU (the upper limit of normal) or a decline of at least 50% from baseline and <65 IU (1.5 times the upper limit of normal).
The patients were randomized to the three treatment arms. The three groups did not differ with respect to baseline demographic and clinical characteristics. Median age was 55, about 70% were white, about 90% had HCV genotype 1, about a fourth of the patients had evidence of cirrhosis, and 40% to 45% had a history of milk thistle use.
Adherence was good, said Fried, as about 90% of the study participants consumed more than 80% of their medication doses.
After six months, one person in the placebo group had a serum ALT ≤45 IU, as did two patients in each of the silymarin arms. Additionally, two patients in the placebo and high-dose silymarin groups had at least a 50% decline in baseline ALT to <65 IU, as did one patient in the 420-mg silymarin arm.
The proportion of patients who met either definition of the primary endpoint was 3.8% (two of 52) in the placebo group, 4% (two of 50) in the 420-mg silymarin arm, and 3.8% (two of 52) in the high-dose silymarin arm.
The three groups also did not differ significantly with respect to the mean change in ALT, change in HCV RNA, or scores on a battery of quality-of-life instruments. A graph of serum ALT levels throughout the six months showed virtually superimposable lines for the three groups.
The placebo and silymarin groups also did not differ significantly in their adverse-event profiles. The most common types of adverse events were gastrointestinal, musculoskeletal, dermatologic, infection, and physical injury. Six patients in the 420-mg silymarin arm and five in the 700-mg arm had serious adverse events, compared with one in the placebo group.
During the discussion that followed the presentation, Fried expressed doubt that using even higher doses of silymarin might lead to better results, as suggested by a member of the audience.
AASLD president T. Jake Liang, MD, said the study is informative because the results showed not only that silymarin performed no better than placebo in a well-controlled clinical trial but also that the substance is not harmful for people who take it for liver conditions.Primary source
: American Association for the Study of Liver DiseasesSource reference
: Fried MW, et al "A randomized, placebo-controlled trial of oral silymarin (milk thistle) for chronic hepatitis C: final results of the SYNCH multicenter study"
AASLD 2011; Abstract 228.