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Lovenox Patent Case Back at Federal Circuit; Generic Versions Still Not Yet Approved

By Aaron Barkoff

Guest post by Robert S. Dailey

The Lovenox patent infringement litigation between Aventis and Teva/Amphastar is making its second trip to the Federal Circuit.  In February, following remand from the Federal Circuit last year, a federal district court in California held that the Lovenox patent is unenforceable due to inequitable conduct.  The appeal may emerge as a litmus test of how far the CAFC is willing to go in lowering the bar on inequitable conduct, especially in terms of what it takes to prove deceptive intent.  In general, the party asserting inequitable conduct must prove each prong of inequitable conduct (i.e., materiality and deceptive intent) by clear and convincing evidence.

In recent cases, the CAFC has expanded the scope of what counts as a material omission, including the omission of information that would have had no bearing on patentability.  Thus, a practitioner may even comply with Rule 56 (37 CFR 1.56), and still be found to have withheld material information.  This bar-lowering has occurred primarily via the emergence of the ?reasonable examiner? standard.  Hence, materiality is judged not by the PTO?s rules, but by a post hoc litigation-induced evaluation of what information a hypothetical ?reasonable examiner? would (or should) have wanted during the ex parte prosecution of the patent application.

Moreover, defendants may no longer need to prove deceptive intent by clear and convincing evidence.  Instead, a ?guilt by omission? standard seems to have emerged.  If the omitted information is ?highly material? and if the patentee cannot proffer a reasonable explanation for the omission, then a court is permitted to infer deceptive intent.  (Of course, the line between ordinary materiality and ?high materiality? is a bit fuzzy, especially if an omission can be highly material even when it would have had no effect on patentability.)

In the Lovenox district court case, the district court went one step further:  The court appeared to have shifted the burden to Aventis to disprove deceptive intent (e.g., after finding that Teva/Amphastar had made out a prima facie case of deceptive intent).  It will be interesting to see where the CAFC goes with this one.

The parties appear reluctant to tread into the legal issues surrounding the CAFC?s recent inequitable conduct jurisprudence.  After all, a sizeable portion of the judges have not yet bought into the recent trend of making it easier to prove inequitable conduct.  Instead, the parties have elected to focus on several alleged clear errors in the district court?s fact-finding.  Perhaps that?s the best approach, anyway.  By their very nature, inquires into an individual?s intent must be fact-intensive. 

Of course, the CAFC may do well to pay more heed to the post-1978 developments in antitrust law, where scholars of all stripes have generally rejected the value of intent-based evidence.  Inequitable conduct arose in 1945 and came of age during that era of legal moralism that emerged from antitrust cases like Standard Oil.  Antitrust law has now largely unburdened itself of Standard Oil and its progeny.  To the degree that inequitable conduct is a relic of that bygone age, why must we retain it in patent law?

Meanwhile, the FDA has still not yet approved any generic versions of Lovenox (enoxaparin sodium).  Lovenox consists of a complex mixture of oligosaccharides that has been shown to have improved anticoagulant effects over other low-molecular-weight heparins (LMWHs).

Earlier this month, Momenta Pharmaceuticals announced that the FDA rejected its ANDA for M-enoxaparin, apparently based on concerns about the generic drug?s immunogenicity.  In other words, the FDA was concerned that it may provoke an unwanted immune response in humans.  Moreover, according to Momenta's press release, "the FDA clarified that all applications for enoxaparin products must address the potential for immunogenicity of the drug product."

Momenta is working with Swiss generic manufacturer Sandoz to develop its generic product.  The news of the rejection caused Momenta?s stock to lose nearly 60% of its value in a single day.  In the intervening weeks, Momenta?s stock value has continued to tumble another 4-5%.

APPEAL BRIEFS:

• Aventis opening brief
• Amphastar opposition brief
• Teva opposition brief
• Aventis reply brief
• Sandoz amicus brief

RELATED READING ON FDA ACTION:

• Bloomberg article
• Pharmalot post
• WSJ Health Blog post

Full post as published by Orange Book Blog: At the Intersection of Patent Law and FDA Law on November 30, 2007 (boomark / email).