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A court in the United Kingdom has ruled that one of Janssen's patents that protected the flunked Alzheimer's disease therapy bapineuzumab is invalid. This was because the court held that the antibody drug was not adequately described in the patent. If the bapineuzumab patent had been valid, Eli Lilly's solanezumab — which is currently in late-stage clinical trials — would have infringed on the bapineuzumab patent.

Janssen's patent (EP(UK)1 994 937) claimed an “antibody directed to amyloid-β that is useful for preventing or treating a disease that is characterized by amyloid deposit in a patient”.

When amyloid precursor protein is cleaved by β- and γ-secretase enzymes, amyloid-β peptides are created, which can then form the plaques that are characteristic of Alzheimer's disease. Antibodies against the amyloid-β peptides — such as solanezumab and bapineuzumab — are thought to induce an Fc-mediated immune response in the brain to clear amyloid-β. Although both antibodies work via the same mechanism, solanezumab targets a middle portion of amyloid-β, whereas bapineuzumab targets an amino-terminal fragment.

Lilly sought to revoke the patent on several grounds, including insufficiency, meaning that the patent did not describe the invention (that is, bapineuzumab) in sufficient detail to enable a skilled person to carry out the invention without undue burden. The court determined that the patent lacked sufficiency from two angles.

First, it highlighted that the claims were overly broad; namely, the patent did not limit the invention to antibodies that targeted a specific portion of amyloid-β (for example, N-terminal fragments). Because of this omission, other skilled people would be presented with a “conundrum of which tests to rely” to achieve the invention and have a high prospect of failure.

Second, the court held that Janssen did not succeed in making an antibody that could achieve the therapeutic effect described in the patent — namely, for preventing or treating a disease characterized by amyloid deposits in a patient. Here, the court found no evidence — such as results from mouse cognition tests — that would allow a skilled person to predict that the reduction in amyloid-β levels induced by bapineuzumab would lead to cognitive benefit in patients. Notably, the court noted that the failure of bapineuzumab to meet its primary end points (based on cognition scores) in a recent Phase III clinical trial added further evidence to show that the claim was not achieved.

Although Eli Lilly's solanezumab also missed its primary end points in a pivotal Phase III trial, it slowed cognitive decline in patients with mild Alzheimer's disease and so is undergoing further testing in this patent population as well as in several prevention trials (see Nature Rev. Drug Discov. 11, 657–660; 2012).

Janssen can appeal the decision.