In re Cyclobenzaprine Hydrochloride Extended-Release Capsule Patent Litigation, Nos. 2011-1399, -1409 (Fed. Cir. Apr. 16, 2012) (Judges Newman, O’Malley, and Reyna)
In this case, the court clarifies that a patent owner is never the beast of burden for a claim of invalidity based on obviousness, and the plaintiffs walked away singing:
Cephalon owns a license to patents that cover an extended-release dosage form for skeletal muscle relaxants, which is marketed as Amrix®, and a method of treating muscle spasms with Amrix®.
In an ANDA litigation involving the Amrix® patents, the district court found that both patents were invalid as obvious in light of the prior art. The Federal Circuit disagreed with the district court’s obviousness analysis in two respects: (1) how the district court interpreted the prior art, and (2) how the district court considered Cephalon’s evidence of “secondary considerations” to show that the patents are not obvious.
The Federal Circuit’s opinion explains in detail why the district court’s take on the prior art was incorrect, but I want to focus on the Federal Circuit’s second point—the approach to secondary considerations. Because patents are presumed valid, a challenger has the burden of showing that a patent is not valid by clear and convincing evidence. Courts consider the prior art as well as so-called “secondary considerations” such as a long-felt need for the invention in the industry, the failure of others to successfully invent the product, and the commercial success of the invention.
The district court first concluded that the defendants had shown that the patents were invalid as obvious. Then the district court looked at Cephalon’s evidence of secondary considerations to overcome its obviousness finding. The problem, the Federal Circuit explained, is that the district court “imposed a burden-shifting framework where none exists.” (See page 21.)
The Federal Circuit called the district court’s error “understandable,” acknowledging that the Federal Circuit has been inconsistent in its articulation of the burden of proof with respect to obviousness. The court has issued several decisions that discuss a “prima facie” case of obviousness being “rebutted” by evidence of secondary considerations. But the court explained that in all cases, the district court has to consider all evidence—prior art and secondary considerations—before it determines whether a patent is invalid for obviousness. In the litigation context, a patent holder never has the burden to show that its patent is NOT obvious. The district court made Cephalon a beast of burden, and Federal Circuit said that’s wrong.
Carry That Weight
The Federal Circuit noted that the district court’s idea of a burden see-saw apparently came from reviewing appeals of cases from the Board of Patent Appeals and Interferences (BPAI). The court explained that a burden-shifting framework makes sense in the prosecution context. Another case from this week demonstrates the Federal Circuit’s point that a patent applicant has to carry some weight.
In re Mousa, No. 2011-1294 (Fed. Cir. Apr. 19, 2011) (Judges Prost, Schall, and Reyna)
The technology in this case is a form of fractionated heparin. Heparin is generally used to as a blood thinner to prevent blood clots from forming, but it’s sometimes used to prevent blood vessel growth in cancerous tissue. Its use in this alternative form is limited because its blood thinning properties can cause bleeding complications. Dr. Mousa’s patent application covered a super-sulfated, oxidized form of heparin fractions. According to the application, this form is an improvement because (1) the increased oxidation allows the heparin to fully block a type of blood vessel growth in tumors, and (2) they have weaker blood-thinning properties, so the bleeding complications can be eliminated.
The patent examiner determined that Mousa’s application was anticipated by another patent, the Naggi patent, which covers heparin treated with strong oxidizing agents that fragment the heparin and create super-sulfated heparin. The examiner stated that the heparin fractions covered by the Naggi patent inherently possess the improvements claimed in Mousa’s application. Then it was Mousa’s job to offer proof to show that the Naggi heparin did NOT inherently possess these characteristics. The BPAI affirmed the examiner’s rejection.
The Federal Circuit explained the balance of burdens in the prosecution context. The examiner first has the burden of providing reasonable proof that a claim limitation is an inherent characteristic of the prior art. Then the burden of proof shifts to the applicant to prove the opposite.
Mousa offered no proof for his arguments that the oxidizing agents in the prior art don’t oxidize every substance or that the Naggi heparin fractions don’t inherently possess the blocking characteristics he disclosed in his application. Without proof, Mousa didn’t meet his burden.
The Weight: Prosecution Versus Litigation
Shifting back to the Amrix® case, the Federal Circuit explained, in a footnote, that the back-and-forth nature of prosecution makes burden-shifting a reasonable approach for considering the obviousness question. A patent applicant can’t respond to a rejection before he knows what the rejection is. So, an examiner can reject a patent application based on a “prima facie” showing of obviousness, and the applicant can “rebut” that rejection with its own proof. Also, in the prosecution context, an examiner only has to determine that an invention is patentable based on a preponderance of the evidence.
In contrast, in the litigation context, patent validity is the issue. The challenger has a higher burden of proof. And the fact finder has all the relevant evidence in front of it before it makes its decision. Given the different context, the Federal Circuit explained that “[t]here is simply no practical need to impose a burden-shifting framework in litigation.”
Patent holders will be glad to know that, when it comes to obviousness defenses, they can take a load off and put the load on the patent challenger:
Photo credit: Jamies Rabbits