Inventors may correct a mistakenly claimed enantiomer, without invalidating their patent if their patent application describes the compound in other ways showing that they were otherwise in possession of the compound.  The US Court of Appeals for the Federal Circuit allowed such a correction in a dispute over daptomycin between Cubist and Hospira.

Cubist Pharmaceuticals, Inc. v. Hospira, Inc., (Fed. Cir. November 12, 2015)

Summary

Cubist’s correction of daptomycin’s mistaken enantiomer didn’t invalidate their patent’s claims because the patent specification described the compound in other ways to show that the inventors “were in possession of the invention” anyway.

Daptomycin Patent – RE 39,071

• The case involved Cubist’s antibiotic daptomycin, US Patent RE 39,071 [Re-issue of US 5,912,226], which Cubist acquired from Eli Lilly.
• S. Patent RE 39,071 claimed the pharmaceutical composition of CUBICIN® (daptomycin for injection) and expired in June 2016 [June 2011 + 5 years Hatch-Waxman Patent Term Restoration].
• Eli Lilly originally filed the daptomycin patent application and the USPTO granted of US 5,912,226, which described daptomycin’s having the L‑isomer of asparagine.
• Cubist requested a U.S. Patent and Trademark Office Certificate of Correction when they discovered that daptomycin’s asparagine residue was the D-isomer instead. The USPTO granted a Certificate of Correction from L-isomer to D-isomer on January 29, 2008 and the FDA relisted the patent in the Orange Book.

Cubist Defeats Hospira’s Challenge and Appeal

Written Description

• Hospira challenged the patent, arguing unsuccessfully that the patent lacked written description. The Court of Appeals for the Federal Circuit (CAFC) sided with Cubist because the patent’s specification did not rely exclusively on the erroneous structural diagram to describe daptomycin.
  • Cubist described daptomycin in two additional ways. Firstly, Cubist described daptomycin using a consistent internal codename. Secondly, the patent specification described a process of making daptomycin, which Cubist successfully established that necessarily resulted in the correct D-isomer.
  • CAFC concluded that the specification “as a whole” showed that Cubist’s inventors had “possession of” daptomycin, even though they may not have had an accurate picture of daptomycin’s entire compound chemical structure.

Recapture Rule

• Hospira also challenged the patent and argued unsuccessfully that the Certificate of Correction improperly broadened the scope of the claims violating the “recapture rule.”

• The CAFC stated that the recapture rule does not apply because (1) the corrected claims are not broader original claims and (2) the amendment was not used to overcome a prior art rejection.

Appeal to Supreme Court Denied

The Supreme Court of the United Stated denied Hospira’s Petition for writ of certiorari on May 31, 2016.