A Lack of Essential Testing Method Parameter in Patent Claims Led to Indefiniteness, but Inequitable Conduct Is Hard to Prove – Lessons from Sun v. Lupin

In a recent District of New Jersey decision, Chief Judge Wolfson found a patent indefinite, obvious, and not infringed (due to a failure of proof). Sun Pharma v. Lupin, 2021 WL 4473411 (Sept. 30, 2021). However, the court did not find inequitable conduct by clear and convincing evidence, despite the inventor’s “hubris” and incorrect understanding of the prior art (his own, earlier patent, no less), in addition to his “possibly gross negligence” during patent prosecution, and his “not credible” testimony at trial.   

Patents Disclosing a Testing Method for a Claimed Property Must Be Sufficiently Detailed

Sun Pharma’s patent (U.S. Patent No. 8,778,999) claims a topical ophthalmic composition containing a polycarbophil polymer and having a viscosity within a certain range. The patent discloses two methods to measure viscosity. The evidence at trial convinced the court that the polymer is thixotropic, meaning that the viscosity will decrease the more you stir it (think Ketchup). Unfortunately for the patentee, there is no generally accepted method in the field on how long to stir a composition before taking the viscosity measurement, and the patent does not give sufficient guidance on this point. Worse yet, two similar compositions (both made and measured by Sun Pharma, the patentee) were shown to have significantly different viscosity after being stirred for different durations. Based on these, the court concluded that the patent is invalid as indefinite. The missing parameter introduced a significant degree of impression.

The lesson here is that when a patent discloses testing methods for a property of the claimed subject matter, the methods must be sufficiently detailed. Of course there is a tension here – if the disclosure is too detailed, it would essentially narrow the scope of the claim. Using the patent in the Sun v. Lupin as an example, if the patent says the method involves stirring the solution for 1-2 min. before viscosity measurement is taken, a generic pharmaceutical company might be able to formulate a bioequivalent product that would have the recited viscosity but only when the product has been stirred for 3 minutes. For an innovator pharmaceutical company, it is important to set forth enough detail in its patents while at the same time taking care not to restrict the patent scope so that a bioequivalent formulation could escape the patent coverage. This is not always easy, as the Sun v. Lupin case demonstrates. 

Testing during Litigation to Prove Infringement also Must Be Sufficiently Detailed

It is somewhat unusual in this case that the expert retained by the patentee was found to have failed to provide sufficient details of his testing to prove infringement. In testing the accused product, the plaintiff’s expert spun it for a “minimum” of one minute, but we don’t know for exactly how long beyond one minute. The court was convinced by the defendant’s expert that different lengths of spin time could lead to very different viscosity measurements, and there might be some impropriety in the plaintiff’s expert’s testing process, i.e. “choos[ing] different times to achieve a result.” The court ruled that the testing result was unreliable,” “vague and imprecise,” and did not prove infringement. 

The interesting thing here is that, things would have been different on the infringement front if the plaintiff’s expert had set, and reported, the spin time he used. The asserted claims do not require any particular spin time—spin time is not in the claims, only viscosity is. Suppose the expert just picked 3 minutes for spin time, and obtained the claimed viscosity measurement each time, and reported that. That could very well have proven infringement, and the parties would move on to fight on the invalidity grounds—which was a tougher fight for the defendant due to the burden of proof. However, if the plaintiff’s expert had started with 1 minute of spinning in his testing, but did not obtain the desired result, he could have spun the already-spun product some more to reduce the viscosity, until he got what he wanted. This may or may not have happened during the Sun case, but the judge had enough doubt about the testing methodology, and disregarded it for the infringement case.

As Elizabeth Holmes’ Lawyer Said, “Failure Is Not Fraud”

In an earlier article (https://ipfdalaw.com/inequitable-conduct-defense-during-patent-litigationin-a-505b2-nda-context/), this author has observed that it is rare for a patent challenger to prove inequitable conduct. The Sun v. Lupin opinion shows us why, once again. In this case, an inventor on the ‘999 patent had an earlier patent on a similar subject matter that, after the trial, was deemed sufficient to invalidate the ‘999 patent as obvious, all by itself. This inventor was very involved in the prosecution of the ‘999 patent, but never disclosed his prior art patent to the PTO. 

Sounds fishy? Lupin’s counsel certainly thought so, and they asserted an inequitable conduct defense against the ‘999 patent. The court found the inventor evasive on the stand, his failure to disclose the prior art “negligent, possibly grossly negligent.” The court thought the inventor had a lot of “hubris.” Since the court found that a person of ordinary skill in the art would have thought the prior art patent sufficient to render the ‘999 patent obvious, it follows that the inventor himself was so blinded by hubris that he could not see what’s plainly obvious. 

Yes, the court did not find the requisite intent on the inventor’s part to support a finding of inequitable conduct, also known as “fraud on the patent office.” This result reminds the author of the ongoing Elizabeth Holmes trial, in which one of the main themes for the defense is that, maybe the defendant was young, incompetent, and overzealous, but that is still not fraud. In the Sun case, negligence, hubris, and being dumb (because of the hubris) actually served effectively as a shield to a demonstration of inequitable conduct. 

How can we help you?

For both brand and generic pharmaceutical companies, similar issues would arise from time to time.  For companies contemplating switching from the generic side to the brand side, like Sun Pharma has done, Upadhye Tang LLP can help with strategy counseling and litigation. Contact Yixin Tang at yixin@ipfdalaw.com or 312-598-2611 for more information. 

About Upadhye Tang LLP 

Upadhye Tang LLP is an IP and FDA boutique firm concentrating on the pharmaceutical and medical device spaces. We help clients with navigating the legal landscape by helping on counseling and litigation. Clients call us to help move drug and device approvals along and to represent them in IP and commercial litigation. Call Yixin Tang at yixin@ipfdalaw.com or 312-598-2611; or Shashank Upadhye, 312-327-3326, or by email: shashank@ipfdalaw.com, for more information. 

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