Clinical And Experimental Study Of Methotrexate And Cyclophosphamide In Patients With Rheumatoid Arthritis

BackgroundRheumatoid arthritis (RA) is a chronic autoimmune disease that usually leads to synovial joint damage and consequent disability. Medical management for RA includes early diagnosis and treatment. Combining disease-modifying antirheumatic drugs (DMARDs) is a widely used therapeutic alternative. However, there is uncertainty surrounding the effective regimen. Further investigation is required to determine the most effective regimen and approach to combination therapy. Based on successful combination therapy in leukocythemia, we first combined methotrexate (MTX) with low dose cyclophosphamide (CTX) to treat RA patients. MTX as prototype agent in RA is a cell cycle special stage agent, while CTX is a cell cycle nonspecial stage agent. During the last decade, the new regimen of combination therapy had been proved to be more effective and safer through we carried on clinical practice.Objective(1)To evaluate the clinical efficacy of MTX, CTX and MTX plus CTX in patients with active RA. (2)To evaluate the safety of MTX, CTX and MTX plus CTX in the treatment of RA. (3)To investigate the parameters predicting the clinical response to three treatment programs. (4)To investigate the change of cell percentage and apoptosis ratio of peripheral blood lymphocytes (PBL) before and after the treatment of RA with MTX, CTX and MTX plus CTX.MethodsThis was a multicenter, randomized, single-blind, controlled clinical study Lasting 24 weeks. 90 patients of active RA were randomized to receive a kind of treatment programs of MTX, CTX and MTX plus CTX. The primary efficacy end point was a response on the American College of Rheumatology 20% improvement criteria (ACR20) at 24 weeks. The secondary end points were responses on the ACR50 and ACR70 improvement criteria, the Disease Activity Score in 28 points, and the European League Against Rheumatism (EULAR) response criteria at 24 weeks. The clinical efficacy and safety were analysed. The parameters predicting the clinical response were analysed with ACR20 as responder by Logistic regression likelihood ratio tests at 24 weeks.Peripheral blood mononuclear cells (PBMC) were collected from 30 patients with RA who randomly received a kind of treatment programs of MTX, CTX or MTX plus CTX respectively and 10 healthy controls. The cell percentage and apoptosis ratio of PBL before and after treatment were detected by Flow cytometry. The observation time was 2 weeks after the patients began to take the drugs.Results1. Efficacy Results1) At week 24, the percent of patients achieving ACR20 in the MTX plus CTX group were significantly higher than that of MTX or CTX group (P<0.05～0.01). The percent of patients achieving ACR50 in the MTX plus CTX group were significantly higher than that of CTX group (P<0.05).2) At week 24, the percent of patients achieving the EULAR moderate response in the MTX plus CTX group were significantly higher than that of MTX or CTX group (P<0.05～0.01). DAS28 scores in MTX plus CTX group were significantly lower than that of MTX or CTX group at week 24 (P<0.05～0.01).3) At week 24, the improvement of patient's assessment of pain, tender joint counts and ESR in MTX plus CTX group were significantly higher than that of MTX group (P<0.05). While the improvement of all assessed parameters in MTX plus CTX group were significantly higher than that of CTX group (P<0.05～0.01). At week 24, The improvement of PF, RP, BP and VT scores in MTX plus CTX group is significantly higher than that of MTX or CTX group (P<0.05～0.01).2. Safety ResultsThere was no serious adverse events. In the MTX, CTX and MTX plus CTX groups, the incidence of treatment related adverse events was 32.1%,30% and 35.7% respectively. There was no statistical difference in all adverse events among three groups (P>0.05). The most frequently occurring in three groups were gastrointestinal complaint and upper respiratory tract infection. The secondary occurring was elevated liver enzyme levels. Most treatment-related adverse events were mild to moderate in severity.3. Predicting Parameters Analysis ResultsLogistic regression analysis showed that age and swollen joint counts predicted ACR20 response.4. The change of cell percentage and apoptosis ratio of PBLIn patients with MTX treatment, Cell percentage of G0/G1 stage of PBL increased and cell percentage of S stage decreased after treatment (P<0.05). There was no significantly difference of cell percentage in patients before and after treatment with CTX (P>0.05). The apoptosis level of patients who received combination therapy is significantly higher than that of patients who received MTX or CTX alone (P<0.05).Conclusion1. Combination therapy with MTX and low dose CTX resulted in significant improvement in patients with active RA. The efficacy of combination therapy was better than MTX or CTX monotherapy.2. Combination therapy is well tolerated and associated with no significant increase in the rate of adverse events compared with monotherapy.3. Age and swollen joint counts were predictive factor of ACR20 response.4. The combination therapy of MTX and CTX can effectively induced the apoptosis of PBL which was blocked on G0/G1 stage in RA patients.