Biologic Tumor Necrosis Factor Inhibitors Research Articles

Single-Stranded DNA Aptamers Against TNF and Their Potential Applications.

Aptamers are short, single-stranded RNA or DNA sequences, which can bind to protein ligands with high affinity and specificity. Applications of aptamers are broad, ranging from drugs and drug delivery vehicles to biosensors. Tumor necrosis factor (TNF) is an inflammatory cytokine that plays a critical role in the pathogenesis of several autoimmune inflammatory diseases. Blocking TNF activity by monoclonal antibodies or TNF receptor fusion protein has been tremendously successful in treating these diseases. However, manufacturing these biological TNF inhibitors is expensive and a significant proportion of patients do not respond to TNF blockade. Here we describe selection of single-stranded DNA aptamers for TNF blockage, and their bioactivity in blocking TNF-mediated cytotoxicity in vitro. These TNF-binding aptamers have the potential to serve as alternatives to biological TNF inhibitors and to be used as in vivo probes for TNF detection.

Biological vs Conventional Combination Treatment and Work Loss in Early Rheumatoid Arthritis

The introduction of biological tumor necrosis factor inhibitors has improved the treatment of rheumatoid arthritis (RA) but at a substantial cost. These drugs have been shown to lead to superior radiological outcomes compared with a combination of conventional disease-modifying antirheumatic drugs over 2 years. To investigate whether radiological superiority translates into better work loss outcomes. Multicenter, 2-arm, parallel, randomized, active-controlled, open-label trial. Patients with early RA (symptom duration <1 year) were recruited from 15 rheumatology clinics in Sweden from October 1, 2002, through December 31, 2005. The study population was restricted to working-age patients (aged <63 years). Patients who did not achieve low disease activity after 3 to 4 months of methotrexate therapy were randomized to receive additional biological treatment with infliximab or conventional combination treatment with sulfasalazine plus hydroxychloroquine. Monthly sick leave and disability pension days 21 months after randomization retrieved from the nationwide Swedish Social Insurance Office register. Main analyses were by intention to treat, including all patients, and adjusted for baseline sick leave and disability pension. Of 204 eligible patients, 105 were randomized to biological and 99 to conventional treatment. Seven patients in the biological and 4 in the conventional treatment group never received the study drug, and 72 and 52 patients, respectively, followed the study per protocol for 21 months. The baseline mean (SD) work loss was 17 (13) d/mo (median, 16 d/mo) in both groups (mean difference, 0.6 d/mo; 95% CI, -3.0 to 3.9). The mean changes in work loss at 21 months were -4.9 d/mo in the biological and -6.2 d/mo in the conventional treatment group (adjusted mean difference, 1.6 d/mo; 95% CI, -1.2 to 4.4). Including only patients receiving at least 1 dose of assigned treatment, the adjusted mean difference was 1.5 d/mo (95% CI, -1.5 to 4.4), and in per-protocol analysis the adjusted mean difference was 0.3 d/mo (95% CI, -2.8 to 3.8). The radiological superiority of biological compared with conventional combination therapy did not translate into better work loss outcomes in patients with early RA who had experienced an insufficient response to methotrexate. clinicaltrials.gov Identifier: NCT00764725.

Brain Protection from Stroke with Intravenous TNFα Decoy Receptor-Trojan Horse Fusion Protein

Tumor necrosis factor (TNF)-α is produced in brain in response to acute cerebral ischemia, and promotes neuronal apoptosis. Biologic TNF inhibitors (TNFIs), such as the etanercept, cannot be developed as new stroke treatments because these large molecule drugs do not cross the blood-brain barrier (BBB). A BBB-penetrating biologic TNFI was engineered by fusion of the type II human TNF receptor (TNFR) to each heavy chain of a genetically engineered chimeric monoclonal antibody (MAb) against the mouse transferrin receptor (TfR), designated as cTfRMAb-TNFR fusion protein. The cTfRMAb domain of the fusion protein acts as a molecular Trojan horse to deliver the fused TNFR across the BBB. Etanercept or the cTfRMAb-TNFR fusion protein (1 mg/kg) was administered intravenously in adult mice subjected to 1-hour reversible middle cerebral artery occlusion up to 90 minutes after the occlusion. Neuroprotection was assessed at 24 hours or 7 days after occlusion. The cTfRMAb-TNFR fusion protein treatment caused a significant 45%, 48%, 42%, and 54% reduction in hemispheric, cortical, and subcortical stroke volumes, and neural deficit, respectively. Intravenous etanercept had no therapeutic effect. Biologic TNFIs can be reengineered for BBB penetration, and the IgG-TNFR fusion protein is therapeutic after delayed intravenous administration in experimental stroke.

Brain-Penetrating Tumor Necrosis Factor Decoy Receptor in the Mouse

Biologic tumor necrosis factor inhibitors (TNFIs) include TNF decoy receptors (TNFRs). TNFα plays a pathologic role in both acute and chronic brain disease. However, biologic TNFIs cannot be developed as brain therapeutics because these large molecule drugs do not cross the blood-brain barrier (BBB). To enable penetration of the brain via receptor-mediated transport, the human TNFR type II was re-engineered as an IgG fusion protein, where the IgG part is a chimeric monoclonal antibody (MAb) against the mouse transferrin receptor (TfR), and this fusion protein is designated cTfRMAb-TNFR. The cTfRMAb part of the fusion protein acts as a molecular Trojan horse to ferry the TNFR across the BBB via transport on the endogenous BBB TfR. cTfRMAb-TNFR was expressed by stably transfected Chinese hamster ovary cells and purified by affinity chromatography to homogeneity on electrophoretic gels. The fusion protein reacted with antibodies to both mouse IgG and the human TNFR and bound TNFα with high affinity (K(d) = 96 ± 34 pM). cTfRMAb-TNFR was rapidly transported into mouse brain in vivo after intravenous administration, and the brain uptake of the fusion protein was 2.8 ± 0.5% of injected dose per gram of brain, which is >45-fold higher than the brain uptake of an IgG that does not recognize the mouse TfR. This new IgG-TNFR fusion protein can be tested in mouse models of brain diseases in which TNFα plays a pathologic role.

Recombinant human tumor necrosis factor receptor (p75) Fc fusion protein (TNFR:Fc) in rheumatoid arthritis.

Tumor necrosis factor (TNF) is the dominant mediator of the cytokine cascade that causes inflammation and joint destruction in rheumatoid arthritis. A new class of agents under investigation, the biologic TNF inhibitors, inhibits the activity of TNF. Recombinant human TNF receptor p75 Fc fusion protein (TNFR:Fc; Enbrel) blocks the activity of the cytokine TNF. The preclinical, Phase I, and Phase II data of TNFR:Fc in rheumatoid arthritis are reviewed in this article. All available data on TNFR:Fc in rheumatoid arthritis were reviewed. These data included published literature and data on file at the manufacturer. TNFR:Fc has been effective in many models of inflammation, including animal models of rheumatoid arthritis and in clinical rheumatoid arthritis trials. Conclusions from a study with TNFR "knockout" mice (genetically altered mice incapable of producing TNFR proteins) demonstrated that p75 TNFR is a natural antagonist of TNF-mediated inflammation. A placebo-controlled, dose-escalation, Phase I trial evaluated the safety and efficacy of TNFR:Fc in patients with rheumatoid arthritis. There were no serious adverse effects reported. A Phase II, randomized, double-blind, placebo-controlled trial evaluated 180 patients with active rheumatoid arthritis whose previous therapy had failed. A dose-response relationship was observed in the number of tender and swollen joints; patients who received the highest dose (16 mg/m2) of TNFR:Fc had the greatest improvement. Treatment was generally well tolerated. TNFR:Fc is nonimmunogenic; no antibodies to TNFR:Fc have been detected thus far in human studies. Preliminary data indicate that TNFR:Fc is an excellent candidate for future long-term studies in the treatment of rheumatoid arthritis.