USPTO to Clarify Guidance on Written Description of Antibodies

The Deputy Commissioner for Patent Examination Policy at the USPTO, Robert W. Bahr, recently issued a memorandum to clarify the applicability of the Office’s written description requirement guidance for claims drawn to antibodies.  The memorandum is a result of the Federal Circuit’s decision in Amgen v. Sanofi, 872 F.3d 1367 (Fed. Cir. 2017) (“Amgen”), in which written description requirement for antibody claims was one of the issues scrutinized by the Court.  As discussed in detail in a post on this website last November, in Amgen the Court found that the USPTO’s written description requirement guidance concerning antibodies was not adequate.

The case was an appeal by Sanofi from a district court’s final judgment holding Amgen’s patents covering the drug Repatha not invalid and granting a permanent injunction enjoining sales of Sanofi’s competing drug Praluent.  As may be recalled, the active ingredient of Repatha is a monoclonal antibody.  So is that of Praluent.  Also, both antibodies lower cholesterol, and do so by the same mechanism.  However, the antibodies differ in structure.  The case began with Amgen suing Sanofi for infringing its patents when Sanofi obtained FDA approval for Praluent.  Sanofi stipulated to infringement, but challenged the patents’ validity on the grounds of written description, enablement, and obviousness.

On the issue of written description, the Federal Circuit took issue with the district court’s jury instructions, objecting specifically to the inclusion in the instructions of the following:

In the case of a claim to antibodies, the correlation between structure and function may also be satisfied by the disclosure of a newly characterized antigen by its structure, formula, chemical name, or physical properties if you find that the level of skill and knowledge in the art of antibodies at the time of filing was such that production of antibodies against such an antigen was conventional or routine.

The Court determined that the instruction was neither legally sound nor based on any binding precedent.  Significantly, it clarified that references to the so-called “newly characterized antigen” test in its previous decisions were not central to the holdings in those cases.  Further, the Court drew attention to Ariad Pharm., Inc. v. Eli Lilly & Co., 598 F.3d 1336, 1351 (Fed. Cir. 2010) (en banc) for making it clear that, to satisfy the statutory requirement of a description of the invention, it was not enough for the specification to show how to make and use the invention, i.e., to enable it.  And yet, according to Court, the jury instruction invited just that improper equation.

The memorandum points to Amgen for stating that the “newly characterized antigen” test could not stand because it contradicted the quid pro quo of the patent system whereby in order to obtain a patent one must describe an invention (the antibody, not the antigen recognized by the antibody).  The memorandum states that in view of Amgen, “adequate written description of a newly characterized antigen alone should not be considered adequate written description of a claimed antibody to that newly characterized antigen, even when preparation of such an antibody is routine and conventional.”

As for specific details, the memorandum states that examples in the Written Description Training Materials issued March 25, 2008 (archived) are outdated and that new examples are being prepared.  Additionally, USPTO personnel are advised to continue following the guidance in the MPEP regarding written description (see, e.g., MPEP 2161.01 and MPEP 2163), except insofar as MPEP 2163 indicates that disclosure of a fully characterized antigen may provide written descriptive support of an antibody to that antigen.  In the same vein, the memorandum draws attention to the 2015-16 training slide set entitled “Antibody Decisions and Their Compliance with the Written Description Requirement,” to state that except for bullet 2 on slide 17, which references the dicta in Centocor that cites to the 2008 USPTO Written Description Training Materials, the contents of the slide remain applicable.

It would be interesting to see what the guidance looks like when ready, because while antibodies share a great deal of structural similarity – arguably a reason for lowering the need for extensive structural details – yet where defining an antibody by function alone or a combination of structure and function is concerned, it may be difficult to determine exactly how much    structure-function correlation data is sufficient.

Adequacy under 35 U.S.C. § 112(a) requires disclosing either a representative number of species falling within the scope of the claimed genus, or structural features common to the members of the genus such that an ordinarily skilled person would be able to visualize or recognize the members of the genus.  It is also worth bearing in mind the Federal Circuit’s cautionary remarks that each case involving the issue of written description must be decided on its own facts, and that the precedential value of cases in this area is extremely limited.  Amgen at 15 (internal citations omitted).