Issue 176 | March 26, 2004
Smithkline Beecham v.
Excel Pharmaceuticals, Inc., et al.

In SmithKline Beecham v. Excel Pharmaceuticals, Inc., et al., Nos. 02-1581, -1612, 03-1011 (Fed. Cir. January 29, 2004), the federal circuit vacated a judgment of noninfringement by Excel of SmithKline Beecham's (Glaxo's) '798 patent, directed to a controlled sustained release formulation of bupropion hydrochloride with HPMC as a sustained release agent.

Glaxo sued Excel based on Excel's paragraph IV certifications alleging that its generic sustained release bupropion hydrochloride would not infringe Glaxo's '798 patent because its generic version contained polyvinyl alcohol (PVA) and not HPMC. Glaxo alleged infringement under the doctrine of equivalents and sought an injunction; Excel moved for summary judgment of noninfringement on the basis of prosecution history estoppel.

In a judgment for Excel, the district court found that HPMC was the key ingredient for achieving sustained release of the active ingredient, bupropion hydrochloride. Many of the original claims did not recite HPMC as a limitation and were rejected for lack of enablement under 35 USC § 112, 1st paragraph. After reviewing the application and the prior art, the Examiner concluded that HPMC was a critical feature of the claimed sustained release formulation, but that the specification, as filed, did not support claims to a broader generic concept since HPMC was the only disclosed sustained release mechanism. In response, Glaxo amended the rejected claims to include HPMC. The amendment was found to be narrowing and the primary issue was whether the prosecution history of the '798 patent barred Glaxo's reliance on the doctrine of equivalents.

Focusing on the state of the art and what was known by the person of ordinary skill in the art, the federal circuit rejected Glaxo’s argument that PVA was unforeseeable simply because Glaxo could not have added PVA to its claims at the time of amendment without drawing a new matter rejection:

In the first place, new matter prohibitions are not directly germane to the doctrine of equivalents or the patentee’s proof to overcome the Festo presumption. . . . [T]he new matter doctrine ensures the temporal integrity of the amendment process in the Patent Office and does not apply to nontextual infringement. [citations omitted]. In fact, the quintessential example of an enforceable equivalent, after-arising technology, would always be unclaimable new matter. In that sense, the doctrine of equivalents compensates for the patentee’s inability to claim unforeseeable new matter.

The federal circuit concluded that the record did not contain sufficient evidence to determine whether PVA was foreseeable as a sustained release agent for bupropion, or whether HPMC and PVA were recognized as interchangeable sustained release hydrogel-forming polymers used in the art of pharmaceutical formulation at the time the claims were amended. Thus, the case was remanded to further develop the record.

To view the full decision visit http://www.aplf.org/mailer/Issue176.doc

To discuss this topic further, please feel free to contact the author Michael R. Dzwonczyk, (mdzwonczyk@sughrue.com), at Sughrue Mion, PLLC in Washington DC., USA.

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