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With Drug Decision, Court Adds New Wrinkle to Patent Corrections

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By Casey C. Sullivan, Esq. on November 16, 2015 9:09 AM

Whoopsie! You've made an error in your patent filing -- one which wasn't discovered until after the patent has been prosecuted and granted. Don't worry, you wouldn't be the first. And instead of leaving you with a garbage patent, the USPTO allows for relatively easy corrections of small mistakes.

Now, thanks to a recent Federal Circuit case, we have a bit more information on just what counts as a small mistake -- and it turns out those mistakes don't have to be too small, after all.

Can I Get a Redo?

When there's a mistake in a patent, the USPTO provides a "certificate of correction," in limited circumstances. The most straightforward cases are when the patent office itself is responsible for an error, one which is "clearly disclosed by the records." If the applicant made the error, however, it must be a good faith mistake that is clerical, typographical, or "of minor character."

How expansive can "of minor character" be? Apparently more so than previously thought. In a Federal Circuit opinion issued last week, Cubist Pharmaceuticals v. Hospira, the court examined a certificate of correction issued after Hospira patented a generic version of Cubist's daptomycin drug. Daptomycin is an antibiotic that treats skin and blood infections and some heart diseases.

The problem, it turned out, was that Cubist got the chemical structure of daptomycin wrong.

Correction or Expansion?

The mistake was hardly Cubist's fault, however. In their patent application, they included a structural diagram which mistakenly identified asparagine amino acids as "L" stereoisomers instead of "D" stereoisomers. That "mistake" was, at the time of filing, simply how everyone believed daptomycin was composed. When researchers later discovered the error, Cubist filed for and was granted a certification of correction, allowing its patents to be reissued with the correct compound structure described.

Hospira, and its generics, were later found to have infringed on Cubist's patents. On appeal to the Federal Circuit, they argued that the USPTO's certificate of correction impermissibly broadened the reach of the patents. The whole chemical structure of the drug was changed, after all, and Hospira would not have infringed on Cubists' patents if they had not been corrected.

The court, however, was not convinced. A chemical structure is "simply a means of describing a compound; it is not the invention itself," the Federal Circuit noted. Correcting that description in light of later scientific understanding was fine -- falling within the "of minor character" corrections the Patent Act authorizes.

Will all patents be so easily corrected following later scientific advances? Probably not. The court's decision was quite fact specific, as Dennis Crouch notes on Patently-O, and may not be easily applied to other circumstances. But, the ruling does highlight that changes "of minor character" don't have to be as minor as one might initially suspect.

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