Anti-inflammatory approaches that target the chemokine network.

Chemokine-ligand/receptor axes play pivotal roles in a myriad of inflammatory, allergic and autoimmune diseases, as well as in the promotion of tumor growth and metastasis. Upon insult, tissue resident cells (and cancer cells in general) release a defined set of inflammatory chemokines that are responsible for the recruitment of activated pathological leukocytes. Recruited leukocytes synthesize and release a host of inflammatory mediators such as chemokines, cytokines, reactive oxygen and nitrogen species, and proteinases. These agents are responsible for the maintenance and amplification of inflammatory responses, and are directly responsible for secondary tissue damage, promotion of autoimmunity, fibrosis and tissue remodelling. Many cancers are associated with the expression of chemokine ligands that co-opt leukocytes such as tumor associated macrophages which in turn provide mediators including growth factors, chemokines and proteinases that promote angiogenesis, tumor growth, and cancer metastasis. Here, we discuss the relevant patents, development and the mechanism of action of a range of therapeutic and potential therapeutic agents that specifically target the chemokine ligand and receptor network. The main approaches that will be highlighted here are antagonism, cell depletion and the relatively unexplored fields of anti-sense, gene and stem cell therapies.

Clinical grade production and characterization of a fusion protein comprised of the chemokine CCL2-ligand genetically fused to a mutated and truncated form of the Shiga A1 subunit.

First generation chemokine ligand-Shiga A1 (SA1) fusion proteins (leukocyte population modulators, LPMs) were previously only obtained in small quantities due to the ribosomal inactivating protein properties of the SA1 moiety which inhibits protein synthesis in host cells. We therefore employed 4-aminopyrazolo[3,4-d]-pyrimidine, an inhibitor of Shiga A1, to allow the growth of these cells prior to induction and during the expression phase post-induction with IPTG. Scale-up allowed the production of gram quantities of clinical grade material of the lead candidate, OPL-CCL2-LPM. A manufacturing cell bank was established and used to produce OPL-CCL2-LPM in a fed-batch fermentation process. Induction of the expression of OPL-CCL2-LPM led to the production of 22.47 mg/L per OD(600) unit. The LPM was purified from inclusion bodies using solubilization, renaturation, refolding and chromatography steps. The identity and purity of the OPL-CCL2-LPM was determined using several analytical techniques. The product retained the ability of the SA1 moiety to inhibit protein synthesis as measured in a rabbit reticulocyte lysate cell-free protein synthesis assay and was cytotoxic to target cells. Binding studies established that the protein exerts its effects via CCR2, the cognate receptor for CCL2. Clinical trials in inflammatory nephropathies are planned.

Long-term efficacy and safety of etanercept in children with polyarticular-course juvenile rheumatoid arthritis: interim results from an ongoing multicenter, open-label, extended-treatment trial.

OBJECTIVE: To evaluate the long-term efficacy and safety of etanercept in children with juvenile rheumatoid arthritis (JRA) participating in an ongoing multicenter, open-label, extended-treatment trial. All patients had been participants in an initial randomized efficacy and safety trial of etanercept. METHODS: Etanercept was administered at a dosage of 0.4 mg/kg (maximum 25 mg) subcutaneously twice each week. Safety and efficacy evaluations were performed every 3-4 months. The JRA 30% definition of improvement (DOI) was defined as improvement of > or =30% in at least 3 of 6 response variables used to assess disease activity, with no more than 1 variable worsening by more than 30%. RESULTS: At the time of analysis, 48 of the 58 patients (83%) were still enrolled in the study; 43 of them (74%) had completed 2 years of treatment. Of these 43 patients, 81% met the JRA 30% DOI, 79% met the JRA 50% DOI, and 67% met the JRA 70% DOI. Ten children started low-dose methotrexate after year 1. Of the 32 children taking prednisone, the dosage was decreased to <5 mg/day in 26 (81%). Two children had serious infections (varicella with aseptic meningitis in one and complicated sepsis in the other). In general, adverse events were of the types seen in a general pediatric patient population. CONCLUSION: Children with severe, longstanding, methotrexate-resistant polyarticular JRA demonstrated sustained clinical improvement with >2 years of continuous etanercept treatment. Etanercept was generally well-tolerated. There were no increases in the rates of adverse events over time. However, children taking etanercept should be monitored closely for infections.

Etanercept versus methotrexate in patients with early rheumatoid arthritis: two-year radiographic and clinical outcomes.

OBJECTIVE: To compare the clinical and radiographic outcomes in patients with rheumatoid arthritis (RA) who received monotherapy with either etanercept or methotrexate (MTX) for 2 years and to assess the safety of this therapy. METHODS: In the Enbrel ERA (early rheumatoid arthritis) trial, 632 patients with early, active RA were randomized to receive either twice-weekly subcutaneous etanercept (10 mg or 25 mg) or weekly oral MTX (mean dosage 19 mg per week) for at least 1 year in a double-blind manner. Following the blinded phase of the trial, 512 patients continued to receive the therapy to which they had been randomized for up to 1 additional year, in an open-label manner. Radiograph readers remained blinded to treatment group assignment and the chronologic order of images. RESULTS: At 24 months, more 25-mg etanercept patients than MTX patients met American College of Rheumatology 20% improvement criteria (72% and 59%, respectively; P = 0.005), and more had no increase in total score and erosion scores on the Sharp scale (P = 0.017 and P = 0.012, respectively). The mean changes in total Sharp score and erosion score in the 25-mg etanercept group (1.3 and 0.66 units, respectively) were significantly lower than those in the MTX group (3.2 and 1.86 units, respectively; P = 0.001). Significantly more patients in the 25-mg etanercept group (55%) than in the MTX group (37%) had at least 0.5 units of improvement in the Health Assessment Questionnaire disability index (P < 0.001). Fewer patients in the etanercept group than in the MTX group experienced adverse events or discontinued treatment because of adverse events. CONCLUSION: Etanercept as monotherapy was safe and was superior to MTX in reducing disease activity, arresting structural damage, and decreasing disability over 2 years in patients with early, aggressive RA.

Preliminary definition of disease flare in juvenile rheumatoid arthritis.

OBJECTIVE: To develop preliminary criteria for defining disease flare in patients with polyarticular-course juvenile rheumatoid arthritis (JRA). METHODS: Data from a randomized clinical trial of etanercept in JRA (51 patients) and the 6 core response variables (CRV) for JRA were used to derive flare definitions. The criterion standard of flare was treatment with placebo. Candidate flare definitions were assessed by receiver-operator characteristic (ROC) curve properties and other statistics for diagnostic tests. RESULTS: Of the possible flare definitions tested with acceptable statistical properties, the one that seemed to be the most useful was worsening in any 2/6 CRV by > or = 40% without improvement in more than 1 of the remaining CRV by > or = 30%. Two other superior flare definitions were (1) worsening in 3/6 CRV by > or = 30% and (2) any worsening of the Childhood Health Assessment Questionnaire, worsening of erythrocyte sedimentation rate by > or = 30% and worsening of the active joint count by > or = 10%. CONCLUSIONS: CRV are useful for defining flare in JRA. Worsening in any 2/6 CRV by > or = 40% without concomitant improvement of more than one of the remaining CRV by > or = 30% appears to be the most suitable preliminary flare definition. Because the proposed flare criteria were derived from a small number of patients, it is essential to perform more definitive testing of this and several alternative flare definitions in larger patient populations.