Rheuminations: Chinese Herb for RA Questioned
by Nancy Walsh, Senior Staff Writer, MedPage Today
June 20, 2014
We recently reported on a randomized study conducted in China in which a plant extract widely used in traditional Chinese medicine was found to be noninferior to methotrexate in patients with rheumatoid arthritis (RA), and had similar rates of adverse events as the drug.
But not everyone agrees that the herbal extract is safe.
In the Chinese study, which was published in Annals of the Rheumatic Diseases, 55.1% of patients receiving extracts of Tripterygium wilfordii Hook F had improved by 50% by 6 months, as had 46.4% of those given methotrexate, and 76.8% of patients using both.
The investigators, led by Xuan Zhang, MD, of the Chinese Academy of Medical Sciences in Beijing, reported that the herbal treatment improved disease activity, pain, tender and swollen joints, erythrocyte sedimentation rate, and patient assessment of function.
The most common adverse events were gastrointestinal, occurring in 29% of patients taking T. wilfordii, in 34.8% of those taking the plant extract plus methotrexate, and in 43.5% of those on methotrexate monotherapy.
Several female patients also developed menstrual irregularities, which is a recognized side effect of the herbal medication, and Zhang and colleagues suggested that the treatment “should be used in postmenopausal female patients and in patients who are no longer interested in having children.”
But a letter to the editor just published in the Annals has raised notable safety concerns with T. wilfordii — and Chinese herbal medicine in general.
“The history of long-term use in China does not establish the safety of [T. wilfordii],” wrote Donald M. Marcus, MD, who is professor emeritus at Baylor College of Medicine in Houston.
Among the points Marcus makes in his letter are that the duration of the study — 24 weeks — was too short to evaluate the safety of a treatment that is likely to be needed for years.
He also objects to the authors’ suggestion that the treatment could be suitable for postmenopausal women, stating, “they do not consider the consequences of a long-term decrease in estradiol, which include osteoporosis, fractures, and possibly cardiovascular and cognitive problems.”
In addition, the treatment can lead to impairments in renal function.
Finally, Marcus pointed out that in Chinese herbal medicine, extracts from other plants, specifically those of the Aristolochia species, have been used for hundreds of years and remain popular, despite their known nephrotoxicity.
He referenced a study conducted in Taiwan by Arthur P. Grollman, MD, of Stony Brook University in New York, who noted that more than 100 years ago, extracts derived from A. clematitis were shown to be nephrotoxic in animals.
Grollman’s study found that about one-third of the Taiwanese population may have used herbal medicines containing Aristolochia and therefore may be at risk for renal insufficiency and urothelial cancer.
“Importantly, the nephrotoxic effects of [aristolochic acid] are irreversible and its carcinogenic effects may not become manifest until 30 or more years after exposure,” Grollman wrote in Environmental and Molecular Mutagenesis.
“The role of aristolochic acids in causing urothelial carcinoma was confirmed by the finding that 60% of upper urinary tract tumors in Taiwan contained aristolochic acid-DNA adducts and signature mutations in the PF53 tumor suppressor gene,” Marcus explained.
While the short-term immunosuppressive and anti-inflammatory properties of T. wilfordiimay be similar to those of methotrexate, this herb shouldn’t be thought of as a “safe alternative” for patients with RA until much more is known about long-term effects, according to Marcus.
“Although [T. wilfordii Hook F] is approved for use in China, it should be considered an experimental therapy whose safety requires further study,” Marcus concluded.
Primary Source
Annals of the Rheumatic Diseases
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