Structural Uncertainty: Understanding the Federal Circuit's Lead Compound Analysis

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  I. INTRODUCTION                                             401      A. Obviousness and Chemical Compounds                    402      B. Development of Lead Compound Analysis                 405      C. Current Application of the Lead Compound Analysis     410         1. Selection of the Lead Compound                     410         2. Motivation to Modify the Lead Compound             412         3. Likelihood of Success                              414  II. PROBLEMATIC ASPECTS OF LEAD COMPOUND ANALYSIS            416      A. Application to Combination Drugs                      417      B. Application to Formulations                           419      C. Lead Compound Analysis and the Requirements of KSR    420 III. TAKEAWAYS                                                423  IV. CONCLUSION                                               425 

I. Introduction

Recently, the Federal Circuit and lower courts have applied a new test to assess the question of obviousness for chemical compounds. While courts have always considered the presence of some lead compound to be relevant to the question of obviousness, beginning at the turn of the millennium, the Federal Circuit began assessing obviousness in a more formulaic fashion, applying what is commonly referred to as the lead compound analysis to determine if a litigant has established a prima facie case of obviousness.

This Paper describes the development of the lead compound analysis, (1) and its application. (2) This Paper then discusses some of the shortcomings and weaknesses of the doctrine's applications (3) and how understanding the lead compound analysis and how it is likely to be applied in typical situations can be useful in understanding both how to draft stronger patents and what ways might be available to attack the obviousness of a chemical compound or a court's application of the lead compound analysis. (4)

A. Obviousness and Chemical Compounds

While the obviousness analysis has always been factually intensive, the parameters for assessing obviousness have remained relatively steady since the United States Supreme Court first addressed obviousness under the 1952 Patent Act in Graham v. John Deere Company. (5) In Graham v. John Deere the Supreme Court laid out four factors for approaching obviousness. First, the scope and the content of the prior art and the claims should be determined. (6) Second, the differences between the prior art and the claims at issue must be ascertained. Third, the level of ordinary skill in the art is determined. And finally, courts consider additional factors such as the commercial success, long felt but unresolved needs, and failure of others. (7)

The Supreme Court's most recent take on obviousness emphasized that the John Deere factors still defined the controlling inquiry. (8) In KSR v. Teleflex, the Supreme Court held that the Federal Circuit's teaching suggestion motivation (TSM) test was overly rigid and the Court emphasized that any approach to obviousness must be a flexible approach. (9) Under the TSM test, the Federal Circuit would determine obviousness of a combination by looking to see if the prior art had some teaching, suggestion, or created some motivation to combine certain elements in the way that the invention did. (10) If a court found that the prior art did contain a teaching, suggestion or motivation, the invention would be obvious.

The TSM test was a high standard for proving obviousness of a chemical compound because it required the prior art to contain language not often found, suggestions of what could be done. KSR lowered the standard for asserting obviousness, holding that the Federal Circuit's standard was not the only approach to obviousness, and that using it alone constituted too rigid of an analysis. After KSR, while a teaching suggestion or motivation might be relevant, lower courts are free to look at things outside the prior art, such as common sense and ordinary creativity. …