Efficacy of T2 in Active Crohn’s Disease: A Prospective Study Report
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- Ren, J., Tao, Q., Wang, X. et al. Dig Dis Sci (2007) 52: 1790. doi:10.1007/s10620-007-9747-y
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To date few therapies have been shown to reliably prevent the evolution of Crohn’s disease (CD). The traditional Chinese medicine, Tripterygium wilfordii Hook F (TWHF), has both immunomodulatory and anti-inflammatory activities. Our aim was to investigate the potential efficacy of T2, the major constituent of extracts of TWHF, in inducing remission of active CD. Twenty adult patients with active CD were enrolled to be treated with T2 pills (60 mg daily) for 12 weeks. Plasma levels of C-reactive protein (CRP), tumor necrosis factor (TNF)-α, and interleukin (IL)-1β were measured at entry and every 2 weeks thereafter until week 12. At each visit the CD Activity Index (CDAI) was calculated. The CD Endoscopic Index of Severity was measured at entry and week 12. Sixteen patients completed the study. A significant decrease in serum levels of CRP, TNF-α, and IL-1β occurred rapidly after commencement of treatment. CDAI scores showed a rapid decline during the first 8 weeks and reached their lowest at week 10. Endoscopic improvements were observed at week 12. In conclusion, T2 appears to be effective for the treatment of mildly or moderately active CD. Further controlled studies are warranted for this promising drug.
KeywordsTripterygium wilfordiiCrohn’s diseaseCrohn’s disease activity indexCrohn’s Disease Endoscopic Index of SeverityTumor necrosis factor-αInterleukin-1β
Up to now few therapies have been shown to reliably prevent the evolution of Crohn’s disease (CD). Controlled studies show that patients with mildly and moderately active CD may respond to corticosteroids . However, corticosteroid treatment cannot be used over a long period without the risk of various steroid-related adverse effects . Nonsteroidal drugs like 5-aminosalicylic acid (5-ASA), azathioprine, 6-mercaptoprine, and infliximab are additional medications for inducing remission . However, expected maximum therapeutic benefit and minimum side effects may be unachievable and the search for more effective and safer medications continues.
T2 is a chloroform/methanol extract of Tripterygium wilfordii Hook F (TWHF), the traditional Chinese medicine, which has both anti-inflammatory and immunomodulatory activities. T2 is also called polyglycosides of Tripterygium wilfordii (GTW) with the components of glucoside, diterpenes, triptolide, and tripdiolide. T2 pills are widely used against inflammatory and autoimmune diseases including a variety of nephropathies, rheumatoid arthritis, systemic lupus erythematosus, and Behcets’ disease . Impressive clinical benefit has been noted in these patients who received T2 for the treatment of arthrositis, a complicated symptom of CD .
Nevertheless, the molecular mechanisms are not yet fully understood. Several studies suggest that the relevant activity resides in the inhibition of synthesis and secretion of pro-inflammatory cytokines via blockage of the NF-κB signaling pathway [6–8]. The immunomodulatory effects can be partially attributed to its potent inhibition of T cell activation, lymphocyte proliferation, and interleukin (IL)-2 production [9, 10]. However, TWHF extract might also block other cytokine targets, such as the cytokine-driven expression of major histocompatibility complex II antigen or inducible nitric oxide (NO) synthase [11, 12]. Chen et al.  demonstrated that TWHF has a cortical hormone-like function and can promote adrenal cortex function by activating the hypothalamus-pituitary-adrenal axis. Ma et al.  previously showed that TWHF extract significantly prevented the tumor necrosis factor (TNF)-α-induced alteration of intestinal permeability which has been found in CD . Recently, Pinna et al.  described the effects of TWHF extract on cytokine secretion by CD biopsies of inflamed intestinal mucosa as well as human peripheral blood mononuclear cells.
And to our observation, the postoperative recurrence rate in patients who received long-term T2 for CD-associated arthrositis seemed lower than in other patients. The outcome was very encouraging and prompted us to undertake this prospective study to assess the safety and efficacy of T2 in a cohort of patients with active CD.
Patients and methods
This was an open, prospective study to evaluate the efficacy and safety of T2 in treatment of active CD with the aim of obtaining data to conduct a large multicenter controlled study. Eligible patients were at least 18 years old and had a definite diagnosis of active CD [17, 18].
Exclusion criteria were septic complications; the presence of other concomitant important disease; use of methotrexate, cyclosporine, azathioprine, mercaptopurine, or any investigational agents within the previous 3 months; current use of any antibiotics; current use of oral prednisolone at a dose of more than 25 mg per day or another corticosteroid at an equivalent dose; and use of enteral or parenteral nutrition.
Patients received T2 pills (Taizhou Pharmaceutical Co., Jiangsu Province, China), 120 mg daily (four 10-mg capsules three times daily). Follow-up visits were carried out every 2 weeks thereafter until 12 weeks.
At each visit, blood samples were obtained in the morning from fasting patients. C-reactive protein (CRP) level was determined by immunoturbidimetry (ITM) on a automatic biochemistry analyzer (COBAS MIRA; Hoffmann-La-Roche, Switzerland). Serum creatinine, blood urea nitrogen, alanine aminotransferase, aspartate aminotransferase, and urine analysis were also evaluated to assess possible toxicity. Remaining blood was immediately separated to serum by centrifugation and kept at −80°C for future assay of TNF-α and IL-1β concentrations, which were determined by enzyme-linked immunosorbent assay (ELISA; Biosource, Camarillo, CA, USA).
At each visit, an interim history including adverse events was recorded, and a physical examination was also performed. The CD Activity Index (CDAI) was calculated from these data . Patients were provided with a diary card which was completed by the patients themselves during the week before the visit. Clinical disease activity is grouped into remission (CDAI, <150), mild (CDAI, 150–220), moderate (CDAI, 220–450), and severe (CDAI, >450) [18, 19].
Endoscopic evaluation (CF240; Olympus, Japan) was performed at entry and week 12 and recorded on tapes or color pictures. Immediately after the procedure, the endoscopist filled out the CD Endoscopic Index of Severity (CDEIS) score as developed and validated by the GETAID. This score is based on the presence of deep or superficial ulceration, the proportion of ulcerated surface, and the presence of ulcerated or nonulcerated stenosis in the terminal ileum and four different segments of the colon .
The study protocol was reviewed and approved by the Ethics Committee for clinical studies involving humans at Nanjing University. Prior to entry, informed consent was obtained from all patients verbally and in writing after they were informed of the purpose of the study and the nature of the procedures involved. Patients were advised that they were free to withdraw from the study at any time without jeopardizing their subsequent care and treatment.
Demographic and clinical characteristics of patients with active CD
Age, yr (range)
Duration of disease, yr (range)
Disease activity, n (%)
Mild (CDAI, 150–220)
Moderate (CDAI, 220–450)
Severe (CDAI, >450)
Location of disease, n (%)
Terminal ileum and colon
Twenty consecutive patients who fulfilled the enrollment criteria were entered into the study between February 2004 and August 2005. Demographic and disease characteristics are listed in Table 1. Before entry, 17 patients were receiving mesalamine and 3 were receiving a tapering dose of prednisolone for the previous 3 months. All agents were discontinued during the trial. CD severity at entry was mild in 6 cases, moderate in 11, and severe in 3.
Four patients were withdrawn before completing the trial. One patient (male, 22 years, moderate at entry) took disallowed medication (mesalamine). One patient (female, 36 years, severe at entry) suspended the intake of T2. Two patients (both males; 59 and 43 years old and mild and moderate, respectively, at entry) refused the endoscopy at the designated time. Therefore, 16 patients completed the study according to the protocol and were available for the final efficacy assessment.
In Fig. 1, CDAI scores showed a rapid decline during the first 8 weeks. The median CDAI score was 295±101 (range, 187–478) at entry and the lowest median, 183±60 (range, 102–278), was reached at week 10 (P < 0.001). This was recorded at the same time as improvement of subjective symptoms. Clinical remission (CDAI, <150) was obtained in eight patients (50%) at week 10 and nine patients (56.2%) at week 12.
Endoscopy after 12 weeks showed marked improvement of diseased mucosa in 10 patients (62.5%). Slight improvement was shown in five patients (31.3%) whose disease severities at entry were all moderate. And one patient (6.3%) whose disease severity was severe at entry remained unchanged. Figure 2 shows near-healing of previously observed colonic ulcerations in two patients (one severe and the other moderate at entry). Figure 3 shows the endoscpic response as expressed by the CDEIS. CDEIS was 12.2±1.5 at entry and decreased to 8.6±2.0 at week 12 (P < 0.01).
Figures 4 to 6 demonstrate the changes in inflammation parameters during the study. A significant decrease in CRP levels was recorded at week 2. This was followed by decreases in TNF-α and IL-1β levels at week 4. CRP levels were 26.5±22.2 mg/L at entry and reached the lowest median level, 8.4±4.9 mg/L, at week 10 (P < 0.01). Similarly, TNF-α levels were 28.6±30.1 pg/ml at entry and reached the lowest median level, 12.9±11.9 pg/ml, at week 10 (P < 0.01). IL-1β levels were 67.5±55.3 pg/ml and reached the lowest median level, 26.0±24.7 pg/ml, at week 12 (P < 0.001).
Three patients developed at least one adverse event. However, no patient discontinued treatment because of adverse events. The most common side effect was diarrhea, which developed in all three patients. The next most common side effects were headache and nausea, which developed in two patients, respectively. A 32-year-old man developed facial rash in the first 3 weeks of the trial and recovered completely at week 6. Hepatic and renal function did not worsen in any patient during the study.
TWHF has been used in China for centuries as a remedy for arthritis and other inflammatory and rheumatic diseases. Initially, a crude water extract (decoction) of TWHF was used, and the dose was adjusted based on the weight of the plant material from which the extract was made. Patients treated with the decoction of TWHF appeared to experience therapeutic benefit but frequently developed adverse effects and toxicity . Subsequently, efforts were made to improve the extraction procedure in order to minimize toxicity and maximize therapeutic benefit. Toward this end, a variety of extraction methods was employed. Among them, ethanol/ethyl acetate extract (triptolide) and chloroform/methanol extract (T2) have been claimed to exert better therapeutic effects and cause fewer adverse events. Nowadays T2 is most widely used in China [21–23].
The mechanism of action of T2 in CD is not well understood. TWHF exerts its effects via blockage of the NF-κB signaling pathway , which plays a role in T cell activation and prduction of pro-inflammatory cytokines such as TNF-α and IL-1β, which are considered to be crucial mediators of inflammatory bowel disease [19, 24]. In the present study, serum concentrations of TNF-α and IL-1β decreased rapidly after commencement of T2 treatment. Therefore T2 may induce remission in active CD by anti-inflammation and immunomodulation.
In recent years the morbidity from CD has increased terribly for unknown reasons in the relatively advanced area of China . There remains no standard therapy to prevent evolution of CD in China. The rationale for using T2 was based on data showing benefits for the therapy of CD-associated arthrositis, and other inflammatory and immunologic derangement disease. The dose of T2 used in the present trial was also referred to the treatment of rheumatoid arthritis and glomerulonephritis.
In view of these, we undertook this prospective study to assess the efficacy and safety of T2 in patients with active CD, T2 treatment was accompanied by marked improvements of clinical symptoms and the colonoscopic appearance of the mucosa and a rapid decrease in inflammatory parameters (CRP, TNF-α, and IL-1β levels).
Furthermore, remarkable clinical benefit was obtained in the absence of severe toxicity. T2 treatment caused no hepatic or renal damage and no significant changes in routine blood biochemistry or urinary analysis. No adverse event was attributed to withdrawal, which suggests the safety and tolerability of T2. In the present study, the disease severities of most patients were mild and moderate. Our data strongly suggest that the indication for T2 treatment should be mild or moderate CD.
Although this study was not designed to evaluate the long-term efficacy of T2 treatment in CD, the present data allow some speculation on the potential of T2 use. One limitation of our data is the lack of a control group. Nonetheless, preliminary observations on clinical response, tolerance, and safety are empirical for designing large, controlled trials. Further, it is appropriate to mention here that the complete remission rate for 5-ASA, commonly used for mild to moderate CD, was 45% at week 8 in the studies reviewed by Thomsen et al.  and 43% at week 16 in those reviewed by Singleton et al. . Therefore, the 56.2% complete remission rate at week 12 achieved in this study is comparable to that for aminosalicylates. And ulceration healing by T2 was seen in some patients in this study. However, this assertion requires our admission that the effects seen in an uncontrolled trial need to be confirmed in large, randomized controlled studies.
In conclusion, T2 may be useful for mildly to moderately active CD. Randomized, controlled trials are required to determine the true clinical benefit of T2. Similarly, the effects of different doses and longer treatment times may need to be investigated. And possibly combination therapy with T2 and other medications may improve the overall outcome.
This study was supported by the National Natural Science Foundation of China (No. 30571797). We thank Moli Zhang for her help in editing the manuscript.