Abiding By The “Original Patent” Rule When Reissuing

Reissue patents allow a patentee to correct an existing patent by broadening or narrowing the originally issued claims. Unfortunately, it’s not as simple as it may sound. Among other requirements, the reissue patent can claim only inventions that were described in the original patent specification as being intended to be a separate invention. Antares Pharma, Inc. v. Medac Pharma Inc., a recent infringement case involving dueling pharmaceutical companies, demonstrates how the so-called “original patent” rule can trip up a patentee.

Shot taken

Antares Pharma holds a reissue patent on jet injection devices for self-administering pharmaceuticals. Antares sued Medac Pharma for patent infringement. The trial court denied Antares’ request for a preliminary injunction because the company failed to show the likelihood of success on its infringement claims. Antares appealed.

On review, the U.S. Court of Appeals for the Federal Circuit focused primarily on the original patent requirement for reissue patents. Under Section 251 of the Patent Act, the original patent specification must expressly describe the particular invention claimed on reissue. According to the Federal Circuit, U.S. Supreme Court cases have recognized this requirement for more than 150 years.

The original patent requirement is analogous to the written description requirement for patent specifications. But, for reissue purposes, the specification “must clearly and unequivocally disclose the newly claimed invention as a separate invention.” It’s not enough that the original patent specification hinted at, suggested or indicated the new invention.

Features aren’t specified

Applying this standard, the appeals court found the relevant reissue claims invalid because the original claims were significantly different in scope and coverage. For example, the originals were limited to “jet injection,” while the reissue claims were focused on particular safety features and didn’t contain the jet injection limitation. The specification, the court said, discussed only one invention — a particular class of jet injectors.

Although the specification mentioned safety features, they were never described separately from the jet injector, nor were the particular combinations of safety features claimed on reissue ever described. The court found the specification contained no description, in an explicit and unequivocal manner, of the particular safety features claimed on reissue that were separate from the jet injection invention. Thus, the original patent requirement wasn’t satisfied, the reissue patent claims were invalid and the preliminary injunction was rightly denied.