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Rheumatoid arthritis is a condition that causes painful inflammation of several joints in the body. The joint capsule becomes swollen, and the disease can also destroy cartilage and bone as it progresses. Rheumatoid arthritis affects 0.5% to 1% of the world’s population. Up to this point, doctors have used various drugs to slow or stop the progression of the disease. But now, ETH Zurich researchers have developed a therapy that takes the treatment of rheumatoid arthritis in mice to a new level: after receiving the medication, researchers consider the animals to be fully cured.
The drug is a biotechnologically produced active substance consisting of two fused components. One component is the body’s own immune messenger interleukin 4 (IL-4); previous studies have shown that this messenger protects mice with rheumatoid arthritis against cartilage and bone damage. ETH scientists have coupled an antibody to IL-4 that, based on the key-lock principle, binds to a form of a protein that is found only in inflamed tissue in certain diseases (and in tumour tissue).
The researchers tested the new fusion molecule, which they refer to as an ‘armed antibody’, in a CTI project together with the ETH spin-off Philochem. They used a mouse model in which the animals developed swollen, inflamed toes and paws within a few days. Among other things, the researchers studied the fusion molecule in combination with dexamethasone, a cortisone-like anti-inflammatory drug that is already used to treat rheumatoid arthritis in humans. The researchers started treating each mouse as soon as they began showing signs of the disease in the form of swollen extremities.
Clinical trials in the next year
When used separately, the new fusion molecule and dexamethasone managed only to slow the progression of the disease in the affected animals. In contrast, the typical signs of arthritis, such as swollen toes and paws, disappeared completely within a few days when both medications were administered at the same time. Concentrations of a whole range of immune messengers in blood and inflamed tissue, which are changed in rheumatoid arthritis, returned to their normal levels. “In our mouse model, this combined treatment creates a long-term cure,” says Hemmerle, who, since completing her dissertation, has been working at Philochem, where she continues the project.
Via Krishan Maggon
This is the first drug to fully cure arthritis in experimental model.
Hemmerle T, Doll F, Neri D: Antibody-based delivery of IL4 to the neovasculature cures mice with arthritis. PNAS, online publication 4 August 2014, doi: 10.1073/pnas.1402783111
Disease-homing antibody–cytokine fusion proteins (immunocytokines) are considered as innovative biopharmaceutical agents for the therapy of cancer and chronic inflammatory conditions with the potential to modulate the activity of the immune system at the site of disease. The immunocytokine F8-IL4 was able to selectively localize to arthritic sites in vivo and exhibited a potent single-agent activity in the collagen-induced arthritis model in mice. Surprisingly, the combination treatment of F8-IL4 with dexamethasone cured 100% of treated mice with established arthritis. To our knowledge, this is the first report of durable and complete regressions in mice with established RA. These findings are of clinical significance as the F8 antibody recognizes its cognate antigen, the extra domain A of fibronectin, with comparable affinity in mouse and man.
The F8 antibody recognizes the alternatively spliced extra domain A of fibronectin, a marker of angiogenesis, which is strongly overexpressed at sites of arthritis. In this study, we investigated the targeting and therapeutic activity of the immunocytokine F8-IL4 in the mouse model of collagen-induced arthritis. Different combination regimes were tested and evaluated by the analysis of serum and tissue cytokine levels. We show that F8-IL4 selectively localizes to neovascular structures at sites of rheumatoid arthritis in the mouse, leading to high local concentrations of IL4. When used in combination with dexamethasone, F8-IL4 was able to cure mice with established collagen-induced arthritis. Response to treatment was associated with an elevation of IL13 levels and decreased IL6 plasma concentrations. A fully human version of F8-IL4 is currently being developed for clinical investigations.