Merck Serono S.A. v. Hopewell Pharma Ventures, Inc

Authored by: Jeremy J. Gustrowsky

The Federal Circuit recently clarified when a prior publication counts as “prior art” against a patent with overlapping inventors. In Merck Serono S.A. v. Hopewell Pharma Ventures, Inc., the court affirmed that a prior disclosure is considered “by another”—and thus prior art—unless there is a complete match between the inventors of the earlier disclosure and the later patent. This ruling impacts how joint research projects and collaborations are treated when it comes to patent validity.

The dispute centered on Merck’s patents (U.S. Patent Nos. 7,713,947 and 8,377,903), which claimed specific dosing regimens for treating multiple sclerosis with oral cladribine. Hopewell challenged these patents, arguing that an earlier patent application by Ivax employees (the “Bodor” reference) disclosed a similar regimen and should count as prior art. Merck argued that because one of its inventors was involved in the joint project and mentioned in related meeting minutes, the Bodor disclosure shouldn’t count as “by another.”

The Federal Circuit disagreed with Merck, holding that unless all inventors of the later patent are also inventors of the earlier disclosure (and vice versa), the earlier disclosure is “by another” and can be used as prior art. The court rejected Merck’s argument that having even one overlapping inventor is enough to exclude a reference from prior art status. This means that any difference in the list of inventors—whether inventors are added or subtracted—makes the earlier work count as prior art.

This decision underscores the importance of carefully documenting inventive contributions in collaborative projects and ensuring accurate inventorship on patent filings. It also highlights that companies cannot sidestep prior art simply by adding inventors to a later patent. For patent holders and applicants, this case is a reminder to pay close attention to inventorship and prior disclosures during the patenting process.