Patenting New Uses for Old Inventions

A bedrock principle of patent law is that old inventions cannot be patented. And a new use for an old invention does not render the old invention patentable. This is because patent law requires novelty—an invention must be new. But while a new use for an old invention does not make the old invention patentable, the new use itself might be patentable. In fact, new-use patents comprise a significant part of the patent landscape—particularly in pharmaceuticals, when drug companies obtain new-use patents to repurpose old drugs. This trend has fueled debates over follow-on innovation and patent quality. But there is a problem with new-use patents that has escaped the attention of legal scholars and commentators. The problem is when an inventor seeks a new-use patent for an old product which is, on close inspection, not new because the old product is really doing the same thing that it did before. This is a technical question that requires some understanding of the underlying science—how and why a result is achieved. But various evidentiary rules, biases, and perfunctory views of novelty preclude a true and accurate patentability assessment. Sometimes this leads to unwarranted patents; other times it derails meritorious inventions.This Article corrects this problem by offering a new framework for evaluating novelty in new-use patent claims. It proposes a probing novelty inquiry which would require inventors to elucidate and disclose mechanistic information to prove that a claimed new use is truly novel. Providing mechanistic information would promote patent law’s disclosure function and improve patent (examination) quality. At a broader level, this Article raises the normative and theoretical question of what it means to be identical—which is what novelty is all about. It also raises policy questions about novelty’s gatekeeping function and its role in promoting broader goals of the patent system