Kazuhiko Inoue

Postmarketing surveillance of the safety profile of infliximab in 5000 Japanese patients with rheumatoid arthritis

Objectives: A large-scale postmarketing surveillance (PMS) study was carried out to determine the safety profile of infliximab in Japanese patients with rheumatoid arthritis (RA). Methods: The PMS study was performed for all patients with RA who were treated with infliximab. They were consecutively registered in the PMS study at the initiation of infliximab treatment and were prospectively monitored with all adverse events noted for a period of 6 months. All case reports, which include safety-related events, were collected monthly. Results: Adverse drug reactions (ADRs) were assessed for 6 months in 5000 patients who were consecutively enrolled in the PMS study. The incidence rates of total and serious ADRs were 28.0% and 6.2%, respectively. “Infections” or “respiratory disorders” were most commonly observed among serious ADRs. Bacterial pneumonia developed in 2.2%, tuberculosis in 0.3%, suspected Pneumocystis jiroveci pneumonia (PCP) in 0.4% and interstitial pneumonitis in 0.5%. Bacterial pneumonia (for which individuals of male gender, of older age and those with advanced rheumatoid arthritis and comorbid respiratory disease were most at risk) began to develop immediately after the start of treatment, while tuberculosis, PCP and interstitial pneumonitis developed about 1 month later. Serious infusion reactions were observed in 0.5% and were more likely to occur in patients who had participated in previous clinical trials of infliximab. Conclusion: This postmarketing surveillance study of patients treated with infliximab showed that infliximab in combination with low-dose MTX was well tolerated in Japanese patients with active RA.

Interleukin–6 and interleukin–8 levels in serum and synovial fluid of patients with osteoarthritis

Concentrations of interleukin (IL)-6 and IL-8 in serum and synovial fluid obtained from patients with osteoarthritis (OA) of the knee were determined by the chemiluminescence-ELISA (CL-ELISA) method, the sensitivity of which is 100-1,000 times greater than that of the conventional ELISA method. The results were compared with those obtained from patients with rheumatoid arthritis (RA) and from healthy subjects. The mean IL-6 and IL-8 levels in synovial fluid indicated higher concentrations in RA than in OA. The IL-6 and IL-8 levels in serum were significantly higher in RA and OA relative to controls. Among OA patients in whom remarkable improvement was noted in hydrarthrosis, the synovial fluid IL-6 and IL-8 levels at the initial examination were relatively higher, and were markedly decreased after treatment with sodium hyaluronate (NaHA). Among those in whom no improvement was noted in hydrarthrosis, the synovial fluid IL-6 and IL-8 levels at the time of initial examination were relatively lower, and hydrarthrosis was not significantly improved even after treatment with NaHA. In addition, there was a tendency for the synovial fluid IL-6 and IL-8 levels to decrease as HA levels increased. Evaluation of X-ray findings revealed that the IL-6 levels in synovial fluid at the initial examination in low-grade cases tended to be significantly higher than in high-grade cases. In low-grade cases, as determined by X-ray findings, there was a significant decrease in IL-6 levels in synovial fluid after treatment with NaHA.

Postmarketing Surveillance of the Safety and Effectiveness of Etanercept in Japan

Objective. Postmarketing surveillance (PMS) was conducted evaluating safety and effectiveness of etanercept (ETN; Enbrel®) in Japan, following all patients with rheumatoid arthritis (RA) during the conditional approval period of ETN. Methods. Registration of patients from 1,334 medical sites was conducted between March 2005 and April 2007. Patients were followed for 24 weeks; data regarding patients’ background, safety, and effectiveness was recorded centrally. Adverse events (AE) and adverse drug reactions (ADR) were coded using the Medical Dictionary for Regulatory Activities. Effectiveness was measured using the Disease Activity Score 28 (DAS28). Results. Of 14,369 patients registered, data collection and evaluation for 7,091 patients by March 2006 is reported. At least 1 AE was observed for 2,173 patients (30.6%); 60% of AE occurred within 8 weeks of starting ETN. Most frequent AE were injection site reaction (n = 377, 5.3%) and rash (n = 228, 3.2%). Serious AE occurred in 403 patients (5.7%); most frequent were pneumonia (n = 59, 0.8%) and interstitial lung disease (n = 42, 0.6%). Pneumonia was the most common specifically important ADR (n = 102, 1.4%). Mean baseline DAS28 was 6.0, which reduced to 4.4 within 4 weeks, and to 3.9 within 24 weeks. The proportion of patients having good or moderate EULAR response measured by DAS28 was 84.1% at Week 24. Effectiveness rates were more favorable in patients concomitantly using methotrexate. Good or moderate EULAR response rate among patients switched from infliximab was 84.9%. Conclusion. This extensive observational trial, including all patients with RA in Japan taking ETN, found ETN to be both effective and well tolerated by Japanese patients with RA. Trial registration: clinicaltrials.gov identifier NCT00503503.

Impact of trough serum level on radiographic and clinical response to infliximab plus methotrexate in patients with rheumatoid arthritis: results from the RISING study

This study is a prospective, randomized, double-blind study to compare the efficacy and safety of 10xa0mg/kg infliximab with those of 3xa0mg/kg infliximab treatment in methotrexate-refractory rheumatoid arthritis patients. After the patients received 3xa0mg/kg infliximab infusion at weeks 0, 2, and 6, they were randomly assigned to be administered 3, 6 or 10xa0mg/kg infliximab every 8xa0weeks from weekxa014 to 46. Mean American College of Rheumatology improvement (ACR-N) at weekxa054, the primary endpoint, was 51.3% and 58.3% for the 3xa0mg/kg and 10xa0mg/kg groups, respectively, with a statistically significant difference. Treatment with 10xa0mg/kg was found to be remarkably beneficial in patients who had not responded to three infusions with 3xa0mg/kg at weekxa010. The median changes in the modified Sharp score were 0.0 in the two groups. There were no significant differences in the incidences of adverse events between the groups. In patients who achieved better clinical response or greater inhibition of progression of joint damage, trough serum infliximab level was significantly higher than in patients who did not. The magnitudes of both efficacies were correlated with the trough serum infliximab level (ClinicalTrials.gov number: NCT00691028).

Synovectomy reduces stromal-cell-derived factor-1 (SDF-1) which is involved in the destruction of cartilage in osteoarthritis and rheumatoid arthritis

We have compared the concentrations of stromal-cell-derived factor-1 (SDF-1), matrix metalloproteinase-1 (MMP-1), MMP-9 and MMP-13 in serum before and after synovectomy or total knee replacement (TKR). We confirmed the presence of SDF-1 and its receptor CXCR4 in the synovium and articular cartilage by immunohistochemistry. We established chondrocytes by using mutant CXCR4 to block the release of MMPs. The level of SDF-1 was decreased 5.1- and 6.7-fold in the serum of patients with OA and RA respectively, after synovectomy compared with that before surgery. MMP-9 and MMP-13 were decreased in patients with OA and RA after synovectomy. We detected SDF-1 in the synovium and the bone marrow but not in cartilage. CXCR4 was detected in articular cartilage. SDF-1 increased the release of MMP-9 and MMP-13 from chondrocytes in a dose-dependent manner. The mutant CXCR4 blocked the release of MMP-9 and MMP-13 from chondrocytes by retrovirus vector. Synovectomy is effective in patients with OA or RA because SDF-1, which can regulate the release of MMP-9 and MMP-13 from articular chondrocytes for breakdown of cartilage, is removed by the operation.

Hypoxia upregulates the expression of angiopoietin-like-4 in human articular chondrocytes: role of angiopoietin-like-4 in the expression of matrix metalloproteinases and cartilage degradation.

The objective of this article was to investigate the role and expression of a novel adipocytokine, angiopoietin‐like‐4 (ANGPTL4), in arthropathy. Human chondrocytes were obtained from articular cartilage of patients with rheumatoid arthritis (RA) and osteoarthritis (OA), who underwent total knee or hip arthroplasty. Isolated chondrocytes were cultured under hypoxic (95% N2, 5% CO2) or normoxic conditions. The effects of hypoxia on ANGPTL4 expression were determined by real‐time reverse transcription polymerase chain reaction and Western blot analysis. We examined the role of ANGPTL4 using small interference RNA or by stimulating chondrocytes with recombinant ANGPTL4 protein. ANGPTL4 expression in the articular cartilage specimens was examined by immunohistochemistry. Hypoxia induced a significant increase in ANGPTL4 production (pu2009<u20090.05). Incubation of chondrocytes in vitro with recombinant ANGPTL4 enhanced the expression of matrix metalloproteinase (MMP)‐1 and MMP‐3. Downregulation of ANGPTL4 mRNA expression by siRNA diminished the expression of MMP‐1, but not that of MMP‐3, suggesting that each proteinase has a distinct response to ANGPTL4. Although the in vitro responses of chondrocytes to hypoxia were similar between RA and OA samples, the in vivo expression of ANGPTL4 had unique disease‐specific patterns, suggesting differences in oxygen tension in vivo. Human chondrocytes expressed ANGPTL4 and the expression was enhanced by hypoxia. ANGPTL4 might modulate cartilage metabolism by regulating MMPs.

Constitutive production of interleukin 6/B cell stimulatory factor-2 from inflammatory synovium.

Interleukin 6 (IL-6) production from synovial tissues of various diseases was examined. Augmented IL-6 production was found in inflammatory synovium not only in RA but also in other kinds of synovitis, including psoriatic arthritis and Behçets disease. Increased amounts of IL-6-mRNA were detected in rheumatoid synovium using a dot blot hydridization technique. Furthermore, there was a positive correlation between IL-6 production and accumulation of plasma cells in the synovium. These findings suggest that IL-6 plays an important role not only in immune response but also in active inflammation in various kinds of synovitis.

Efficacy of arthroscopic synovectomy for the effect attenuation cases of infliximab in rheumatoid arthritis

To investigate whether arthroscopic synovectomy is effective for nonresponders to infliximab, anti-tumor necrosis factor-α antibody, for the treatment of rheumatoid arthritis (RA), we assessed seven patients including ten arthroscopic synovectomies in knee joint, in shoulder joint, and in ankle joints. We compared C-reactive protein (CRP) and DAS28 (ESR) before and after surgery at 6 and 50xa0weeks. After arthroscopic synovectomy, we continued the infliximab treatment with methotrexate in a routine manner. We detected synovium proliferation with vascular increase in patellofemoral joint and around the meniscus and femoral and tibial side of the anterior cruciate ligament in the knee joints. We also found synovial proliferation in rotator interval in the glenohumeral joint and fatty changing in subacromial bursa in the shoulder. In the ankle joint, we found synovial proliferation with white meniscoid between tibiofibular joint to develop impingement. Serum CRP was improved from 3.45±0.4 to 1.12±0.2 at 6xa0weeks to 1.22±0.4 at 50xa0weeks after arthroscopic synovectomy. There is no severe side effect of arthroscopic synovectomy during infliximab treatment; however, one patient had slight rash that was improved. DAS28 was improved from 5.58±0.23 to 3.87±0.47 at 6xa0weeks to 2.58±1.49 at 50xa0weeks after arthroscopic synovectomy. It is possible that arthroscopic synovectomy can be one of the effective methods to continue with the infliximab treatment when its efficacy decreased or in the nonresponders of infliximab for RA patients.

ELASTASE FROM POLYMORPHONUCLEAR LEUKOCYTE IN ARTICULAR CARTILAGE AND SYNOVIAL FLUIDS OF PATIENTS WITH RHEUMATOID ARTHRITIS

SummaryObjective was to study the significance and the mechanism of action of elastase from polymorphonuclear leukocyte (PMN elastase) in patients with rheumatoid arthritis (RA). The experiments conducted consisted of two phases. Firstly, articular cartilage and synovia from 8 patients with RA undergoing total knee replacement were obtained, and the gelatinolytic enzyme activity was extracted with 2M guanidine hydrochloride. The gelatinolytic activity of each tissue was measured to confirm that the activity was due to PMN elastase by using an antihuman leukocyte elastase antibody. Secondly, the levels of PMN elastase-α1 proteinase inhibitor complex (EIC) in the blood and synovial fluid of 170 patients with RA were measured by immunoassay. The results were as follows: 1. Gelatinolitic activity was shown to be mainly due to PMN elastase, and found to be highest in cartilage and synovia in RA joints. 2. The EIC levels in plasma of RA patients were significantly higher than those in gout and osteoarthritis (OA), and the EIC levels increased according to the stage of articular cartilage destruction. Moreover, the EIC levels in synovial fluid of RA patients were higher compared to those of OA patients. The activity of PMN elastase was elevated in destructive joints of RA. With the progression of articular cartilage destruction, EIC levels in plasma of RA patients increased as well. We suggest that PMN elastase may play a significant role in RA disease.

Inducement of mitogen-activated protein kinases in frozen shoulders

BackgroundMitogen-activated protein (MAP) kinases are well-known molecules that play key roles in mechanical stress signals during skeletal development. To test our hypothesis that the synovium in frozen shoulders is induced by MAP kinases, immunohistochemical analyses for detecting expression and signal transduction of MAP kinases were performed in synovial tissue obtained from the rotator interval (RI) in frozen shoulders.MethodsSynovial tissues were examined from 10 frozen shoulder patients with a mean age of 55.4 years (46–62 years). Synovial tissues between the long head of the biceps tendon (LHB) and the RI in frozen shoulders were stained with hematoxylin and eosin (H&E) and then examined with immunohistochemical staining. Extracellular signal-regulated (ERK), the Jun N-terminal (JNK), and p38 mitogen-activated protein (MAP) kinases, nuclear factor κB (NF-κB), p50, CD29 (β1-integrin), matrix metalloproteinase (MMP)-3, interleukin-6 (IL-6), CD56, CD68, S-100, and vascular endothelial growth factor (VEGF) were analyzed to detect expression patterns.ResultsH&E showed vascular proliferation with fibrin and fibrous tissue in the synovium of frozen shoulders. ERK was expressed in the epithelial cells of vascular tissue, and JNK was expressed strongly in the interstitial cells around vascular tissue; p38 MAPK was not expressed. NF-κB was expressed in vascular tissue, and IL-6 was expressed around vascular tissue. CD29 (β1-integrin) was expressed in vascular tissue and in superficial cells of synovial tissue. MMP-3 and VEGF were expressed on the surface layer of synovial tissue and vascular tissue, and CD68 was expressed on the surface layer. Nerverelated proteins, CD56 and S-100, were expressed weakly.ConclusionsMechanical stress on the LHB and RI in the shoulder may induce ERK and JNK to express NF-κB by CD29 to develop capsule contracture, producing MMP-3, IL-6, and VEGF.