Benefit of an extract of Tripterygium Wilfordii Hook F in patients with rheumatoid arthritis: A double‐blind,placebo‐controlled study

Objective

To examine the safety and efficacy of an extract of Tripterygium wilfordii Hook F (TWHF) in the treatment of patients with rheumatoid arthritis (RA).

Methods

An ethanol/ethyl acetate extract from the roots of TWHF was prepared and used in a prospective, double‐blind, placebo‐controlled study in patients with longstanding RA in whom conventional therapy had failed. Patients were randomly assigned to receive either placebo or low‐dose (180 mg/day) or high‐dose (360 mg/day) extract for 20 weeks, followed by an open‐label extension period. Clinical responses were defined as 20% improvement in disease activity according to the American College of Rheumatology criteria. Side effects were actively queried and recorded at each visit.

Results

A total of 35 patients were enrolled in the trial; 21 patients completed the 20‐week study. One patient from each group withdrew because of side effects. Twelve, 10, and 10 patients in the placebo, low‐dose, and high‐dose groups, respectively, completed at least 4 weeks of treatment. Of these patients, 8 and 4 in the high‐dose and low‐dose groups, but none in the placebo group, met criteria for clinical response. Four, 4, and 7 patients in the placebo, low‐dose, and high‐dose groups, respectively, were enrolled in the open‐label extension; of these, 2, 4, and 5 patients, respectively, met criteria for clinical response. The most common side effect was diarrhea, which caused 1 patient in the high‐dose group to withdraw from the trial. No patients withdrew because of adverse events during the open‐label extension.

Conclusion

The ethanol/ethyl acetate extract of TWHF shows therapeutic benefit in patients with treatment‐refractory RA. At therapeutic dosages, the TWHF extract was well tolerated by most patients in this study.