Amgen v. HMR: a case for deference in claim construction.

• Author: Brown, Andrew S.

TABLE OF CONTENTS I. INTRODUCTION II. BACKGROUND A. Facts and Procedural History B. Construction of "Therapeutically Effective Amount" C. Denial of En Banc Rehearing III. THE MARKMAN-CYBOR REGIME A. De Novo Review in Claim Construction B. The Arguments Against De Novo Review IV. ANALYSIS A. Claim Construction Accuracy in the Federal Circuit B. The Future of Markman-Cybor C. Supreme Court Review V. CONCLUSION I. INTRODUCTION

In Amgen Inc. v. Hoechst Marion Roussel, Inc. (Amgen V), (1) the Court of Appeals for the Federal Circuit was once again faced with the difficult question of the proper standard of review in claim construction appeals. The case went back and forth between the district court and the Federal Circuit multiple times before eventually narrowing on the construction of a single claim term. Ultimately, a petition for rehearing en banc was filed arguing that the Federal Circuit panel should have afforded more deference to the district court's claim construction. The petition was denied, but a number of dissenting and concurring opinions underscored the conflict among the Federal Circuit judges. Subsequently, a petition for a writ of certiorari was filed. (2)

Currently, claim construction is reviewed de novo on appeal. This rule was first announced in Markman v. Westview Instruments, Inc. (Markman I), (3) and was confirmed by the Federal Circuit in Cybor Corp. v. FAS Technologies., Inc. (4) But the rule has not been without detractors, especially given the high reversal rate in claim construction cases. Both academics and jurists have criticized the holding in Cybor and called for increased deference to district court claim constructions. One of the most basic assumptions often made in the debate about the proper standard of review in claim construction cases is that the district court erred when a Federal Circuit panel reverses a district court claim construction. There is reason, however, to doubt this assumption. The Federal Circuit is certain to confront the MarkmanCybor rule again, but the exact adjustments it will make remain unclear. Ultimately, though, the Federal Circuit is unlikely to do enough. For this reason, Supreme Court review is warranted.

2. BACKGROUND

   1. Facts and Procedural History

      Amgen is the owner of several patents that cover the production of erythropoietin ("EPO"), a naturally-occurring hormone that regulates red blood cell production. (5) Amgen sells EPOGEN, an embodiment of the patented EPO, to be used in treating anemia. (6) U.S. Patent No. 5,955,422 ("the '422 Patent"), the patent at issue, was issued to Kirin-Amgen (7) on September 21, 1999. (8) Claim 1 of the '422 Patent reads: "A pharmaceutical composition comprising a therapeutically effective amount of human erythropoietin and a pharmaceutically acceptable diluent, adjuvant or carrier, wherein said erythropoietin is purified from mammalian cells grown in culture." (9) In April 1997, Amgen filed a declaratory judgment action in district court alleging that an Investigational New Drug Application filed by Hoechst Marion Roussel (now known as Aventis Pharmaceuticals, Inc.) and Transkaryotic Therapies, Inc. (collectively, "HMR") infringed several of Amgen's EPO patents. (10) In October 1999, Amgen amended the complaint to add the '422 Patent and one other patent that had issued after the suit was filed. (11) In January 2001, after an extensive trial, the district court issued a lengthy opinion in which it held three patents, including the '422 Patent, valid and infringed. (12) HMR appealed to the Federal Circuit on several grounds, arguing in part that the district court's validity determinations were erroneous. (13) In reference to the '422 Patent, the Federal Circuit panel held that the district court had erred in failing to construe explicitly the term "therapeutically effective," which the panel deemed necessary to determine whether the '422 Patent was anticipated by a prior art clinical study. (14) On remand, the district court construed "therapeutically effective amount" as "a quantity that produces a result that in and of itself helps to heal or cure" a certain class of patients. (15) Accordingly, it upheld its prior decision finding the '422 Patent valid and infringed. (16)

      HMR appealed once again, contesting all of the district court's rulings, (17) and the Federal Circuit panel reviewed de novo the district court's construction of the term "therapeutically effective amount." (18) In August 2006, a divided panel reversed the district court's claim construction. (19) The panel held that a "therapeutically effective amount" was an amount that elicited any one of several in vivo effects described in the patent, including, but not limited to, an increase in hematocrit, with no requirement that the amount be useful for healing or curing. (20) The case was once again remanded to the district court to determine the issue of validity in light of the new claim construction. (21)

   2. Construction of "Therapeutically Effective Amount"

      To construe the term "therapeutically effective amount," the panel majority relied heavily on a passage in the patent specification that states:

      [T]o the extent that polypeptide products of the invention share the in vivo activity of natural EPO isolates they are conspicuously suitable for use in erythropoietin therapy procedures practiced on mammals, including humans, to develop any or all of the effects [before] attributed in vivo to EPO, e.g., stimulation of reticulocyte response, development of ferrokinetic effects (such as plasma iron turnover effects and marrow transit time effects), erythrocyte mass changes, stimulation of hemoglobin C synthesis and, as indicated in Example 10, increasing hematocrit levels in mammals. (22) The majority read this section as defining all of the effects that the claimed invention could be used to produce in therapy. (23) Accordingly, the majority concluded that the term "therapeutically effective" did not require the claimed EPO to increase hematocrit nor cure disease, but simply to elicit one or more of these effects. (24)

      Chief Judge Michel dissented, urging adoption of the district court's construction. (25) He argued that causing one of the effects of therapy is not the same as therapeutic effectiveness. (26) "Therapeutically effective," according to Chief Judge Michel, was used by the patentee in the "ordinary sense of the phrase to mean promoting 'healing' or 'curing.'" (27) Rather than alter that meaning, the patentee affirmed it by listing certain effects previously attained by prior art EPO, with the addition that the claimed EPO also increases hematocrit, (28) which is necessary for healing. (29) For this construction, Chief Judge Michel relied in part on the relationship between an increase in hematocrit and the other biological effects listed in the specification. (30) As the district court stated, in most cases "an increase in hematocrit is accompanied, if not preceded, by 'any or all' of the biological effects listed in the specification." (31) By listing both, the patentee intended "to claim EPO that (1) causes the same in vivo biological effects as the natural EPO; and also (2) increases hematocrit." (32)

      As additional support, Chief Judge Michel pointed out that one of the passages relied upon by the majority referred to analogs of EPO and not the claimed EPO. (33) Therefore, the passage should not have been used to limit the claim. (34) Finally, Chief Judge Michel argued that his construction of "therapeutically effective" was supported by the prosecution history, where the patentee differentiated the claimed EPO from the prior art by pointing to its ability to treat patients. (35)

   3. Denial of En Banc Rehearing

      In response to the decision in Amgen IV, Amgen filed a petition for rehearing en banc, arguing that the majority erred in the construction of "therapeutically effective amount" and should have afforded more deference to the district court's construction. (36) Although Amgen's petition was denied, four of the twelve Federal Circuit judges dissented and urged reconsideration of the Markman-Cybor rule of de novo review of claim construction. (37) Three other judges concurred in the denial of rehearing en banc but expressed a willingness to reconsider the rule given an appropriate case. (38)

      Chief Judge Michel, who had dissented in the original panel decision, reiterated his dissent and was joined by Judge Rader. (39) He first pointed to four practical problems created by the Markman-Cybor regime: (1) a high reversal rate of claim construction; (2) a lack of predictability, which confounds trial judges and discourages settlements; (3) loss of the comparative advantage held by district court judges; and (4) inundation of the Federal Circuit with the minutiae of claim construction. (40) Next, he questioned the traditional analogy between claim construction and statutory interpretation, noting that claim construction necessarily involves factual determinations and that trial judges may be better equipped to make such determinations. (41)

      In her dissent, Judge Newman first argued that the panel majority had misconstrued "therapeutically effective." (42) Thereafter, she stated her belief that the Federal Circuit should grant en banc review to correct errors of claim construction because the Federal Circuit has an obligation to provide consistency in construing claims. (43) She wrote that since claim construction is treated as a matter of law, the correct construction falls squarely within the criteria for rehearing en banc. (44) Ultimately, she suggested that the Federal Circuit's review of findings of the technology-based facts inherent in claim construction should be guided by the Supreme Court's Daubert (45) decision. (46) She indicated that providing due deference to findings based on factual evidence would take advantage of the district court's procedures and adjudicatory skills, which are better suited to such mixed...