Population PK-PD Model for Tolerance Evaluation to the p38 MAP Kinase Inhibitor BCT197.

The p38 mitogen-activated protein kinase (p38) is a key signaling pathway involved in regulation of inflammatory cytokines. Unexpectedly, several clinical studies using p38 inhibitors found no convincing clinical efficacy in the treatment of chronic inflammation. It was the objective of this study to characterize the population pharmacokinetics (PK) of BCT197 in healthy volunteers and to examine the relationship between BCT197 exposure and pharmacodynamics (PD) measured as inhibition of ex vivo lipopolysaccharide (LPS)-induced tumor necrosis factor alpha (TNFα), a downstream marker of p38 activity. PK was characterized using a two-compartment model with mixed-order absorption and limited-capacity tissue binding. The PK-PD relationship revealed that suppression of TNFα was partly offset over time, despite continuous drug exposure. This may indicate a mechanism by which the inflammatory response acquires the ability to bypass p38. Simulations of posology dependence in drug effect suggest that an intermittent regimen may offer clinical benefit over continuous dosing and limit the impact of tolerance development.

EULAR response criteria for polymyalgia rheumatica: results of an initiative of the European Collaborating Polymyalgia Rheumatica Group (subcommittee of ESCISIT).

OBJECTIVE: To develop response criteria for polymyalgia rheumatica (PMR) for monitoring treatment and comparing alternative treatments regimens. METHODS: 76 patients, mean (SD) age 68.7 (7.7) years, were enrolled. Corticosteroids, and non-steroidal anti-inflammatory drugs (NSAIDs) were the only drugs allowed during the observation period. Erythrocyte sedimentation rate (ESR), C reactive protein (CRP), alpha(2) globulin, serum iron, pain, physician's global assessment (PGA), morning stiffness (MST), muscle tenderness (MT), myalgia, and the elevation of upper limbs (EUL) were determined regularly. The daily corticosteroid and NSAID doses as the corticosteroid response time were recorded. To ensure evaluation of an adequate number of patients (n = 57) week 24 was chosen for final analysis. RESULTS: ESR, CRP, alpha(2) globulin, pain, PGA, MST, myalgia, MT, and EUL showed significant improvement (p<0.0001) at week 24 compared with week 0. Multiple regression analysis showed that changes of ESR (p = 0.08), CRP (p = 0.41), alpha(2) globulin (p = 0.13), MST (p = 0.1), and MT (p = 0.07) were independent of pain, but myalgia (p<0.001) and EUL (p = 0.003) were pain dependent. Consequently, a core set of PMR response criteria, comprising ESR or CRP, pain, PGA, MST, and EUL was established. Assessment of treatment responses with this core set resulted in 90%, 70%, 50%, and 20% improvement in 31/57 (54%), 46/57 (81%), 51/57 (89%), and 54/57 (95%) of the patients, respectively. CONCLUSION: These PMR response criteria are a promising tool for better monitoring of disease activity and treatment in PMR. It is proposed that these criteria should be used in clinical trials in the near future to explore alternative treatment options for PMR.

Autoantibodies in early arthritis: advances in diagnosis and prognostication.

Several excellent reviews have recently been published on the significance of autoantibodies in rheumatoid arthritis (RA) (1-4). Here we: (i) review selected longitudinal studies examining the predictive utility of autoantibodies in early arthritis and early RA cohorts; (ii) assess the relevance of autoantibodies as an independent parameter for prediction and prognostication of RA; and (iii) describe the potential of multiplex autoantibody assays, including miniaturized, high-throughput microarray technology, to improve diagnosis and prognostication in recent-onset synovitis/early arthritis patients.

Sensitivity and specificity of anti-Sa autoantibodies for rheumatoid arthritis.

OBJECTIVE: To assess the sensitivity and specificity of the recently described anti-Sa autoantibodies in order to determine their potential usefulness for the diagnosis of rheumatoid arthritis (RA). METHODS: Sera from 67 patients with RA (including 31 patients with early RA of <3 months duration), from 180 patients with other rheumatic diseases and from 30 healthy control subjects were investigated by immunoblotting employing partially purified Sa antigen. Additionally, all sera were tested for rheumatoid factor (RF), anti-A2/RA33, antinuclear antibodies (ANA) and ANA subsets. RESULTS: Twenty-one (31%) of the 67 patients with RA, but only four of the 180 control patients, were anti-Sa positive; therefore, anti-Sa was approximately 98% specific for RA. Anti-Sa was not associated with either RF or with anti-A2/RA33. The latter antibody was present in 21 RA sera, only eight of which also contained anti-Sa. Thus, 34 RA sera (51%) showed at least one of these two autoantibodies and, importantly, 18 of these sera were RF negative. Furthermore, of the 31 patients with early RA, 12 (40%) were anti-Sa and/or anti-A2/RA33 positive. CONCLUSION: Although the numbers studied remain small, taken together, these data suggest that anti-Sa may represent a promising novel serological marker with high specificity for RA.

Chronic lower back pain due to sarcoma.

We describe a 74-year-old woman with extensive pelvic leiomyosarcoma presenting with uncharacteristic musculoskeletal pain of the lumbosacral region and left lower extremity. Hemipelvectomy was considered the treatment of choice, and a model for a pelvic prosthesis was constructed based on imaging analysis. However, the tumour (and the complaints) responded surprisingly well to a combined treatment regimen including superselective arterial catheter embolization, which led to tumour regression to such a degree that aggressive surgical treatment became unnecessary.