Obviousness Ruling Based on Mischaracterizations of Reference Overturned by CAFC

I, like many other patent prosecutors, have experienced frustration when a patent examiner makes an obviousness rejection under 35 U.S.C. § 103 (or an anticipation rejection under 35 U.S.C. § 102) based on a mischaracterization of what a reference fairly teaches.  The height of a patent prosecutor’s angst occurs when the Board of Appeals and Interferences (BPAI) also adopts findings of fact based on such mischaracterizations.

In In re Chapman, the BPAI made not one, but three mischaracterizations of what the primary reference fairly taught.  Two of those mischaracterizations on which the BPAI’s obviousness ruling was based were later deemed to be significant by the Federal Circuit.  And fortunately for the patent applicant, the Federal Circuit didn’t treat these two significant mischaracterizations as “harmless errors” because “they increase the likelihood that [the patent applicant] was erroneously denied a patent on grounds of obviousness.”

The technology in Chapman relates to “dumbbell-shaped” divalent antibody fragments such as those shown below in Figure 2:

The F(ab’)2 fragment shown in Figure 2 comprises two Fab’ “arms.”  Each “arm” comprises one light chain and one heavy chain (each represented as a solid rectangle) which are “linked” by a disulphide bridge (represented as a “-S-S-“ structure) formed by SH groups from the respective cysteine residue of each chain in the “arm.”  As indicated in Figure 2, the upper end of each “arm” forms an antigen-binding site, thus making the F(ab’)2 fragment “divalent” because it has two such sites.  The lower end of each “arm” (the “hinge region”) are also connected (“linked”) together by a disulphide bridge.

The claimed invention in Chapman was directed to divalent antibody fragments like those shown in Figure 2 but with the light chain (one rectangle) of each “arm” being removed.  The remaining heavy chains were also connected together by at least one “intervening” polymer to form at least one nondisulphide “interchain” bridge” between the heavy chains.  Also importantly, each end of this “intervening” polymer was covalently bonded to the respective heavy chain at the SH group of a cysteine residue of the heavy chain (e.g., a cysteine residue in the “hinge region”).  The alleged benefit for this “intervening” polymer was that it increased the circulating half-life of the antibody fragment for therapeutic purposes.

The patent examiner rejected the claimed invention under 35 U.S.C. § 102(e) as anticipated by U.S. Pat. No. 6, 025, 158 (“Gonzalez”), or alternatively as obvious under 35 U.S.C. § 103(a) over Gonzalez alone, or further in view of U.S. Pat. No. 5,436,154 (“Barbanti”).  Like the claimed invention, the primary Gonzalez reference described linking antibody fragments to a polymer to increase an antibody’s circulating half-life for therapeutic purposes.  The other relevant teachings of Gonzalez were:  (a) a single antibody fragment linked to a polymer(s), including a “dumbbell-shaped” structure made up of two antibody fragments joined by a polymer; (b) identification of six possible choices for the antibody fragment which included the Fab’ antibody fragment; (c) attaching the polymer to a particular amino acid residue or a particular region, including doing so without using a disulphide bond; and (d) a preference for the cysteine residue as an attachment point, particularly a cysteine residue in the “hinge region” of the antibody fragment.  (Barbanti was relied upon to describe the use of antibodies for in vivo therapy).

On appeal, the BPAI reversed the patent examiner’s anticipation rejection.  But the BPAI also affirmed the patent examiner’s obviousness rejection.  The BPAI’s factual findings for affirming the obviousness rejection included the following three statements which became the focal point of the subsequent appeal to the Federal Circuit in Chapman:

1.         “[T]he Examiner finds Gonzalez teaches a dumbbell-shaped antibody structure comprised of two monovalent Fab’ fragments (FF 8, 12) and describes linking them via a polymer molecule.”

2.         “Gonzalez describes a divalent antibody in which the polymer is linked between light and heavy chains and only one cysteine residue is present (emphasis in the original).”

3.         “[t]he antibody can be a monovalent Fab fragment, a monovalent Fab’ fragment which includes one or more cysteine residues in the constant region, or an F(ab’)2 antibody fragment which has a hinge cysteine between the Fab’ fragments.”

In the appeal to the Federal Circuit, the patent applicant initially argued that Gonzalez taught away from two aspects of the claimed invention:  (i) using the “hinge” cysteine as an attachment point for the “intervening” polymer; and (ii) using this “intervening” polymer as a bridge between two F(ab’)2 fragments.  But this “teaching away” argument didn’t resonate at all with the Federal Circuit.

The patent applicant found a more receptive ear with the Federal Circuit when it argued that the above three BPAI statements were not supported by “substantial evidence.”  In fact, the USPTO agreed that these three statements were “erroneous” but were “harmless error.”  Like the patent applicant’s initial “teaching away” argument, the USPTO’s assertion of “harmless error” didn’t fly with the Federal Circuit, at least with regard to the BPAI’s second and third statements.

Regarding the BPAI’s first statement, the USPTO agreed that “that Gonzalez does not teach linking “two monovalent Fab’ fragments . . . via a polymer.”  The Federal Circuit also agreed with USPTO that the BPAI’s obviousness ruling wasn’t based on this first statement, “but was simply (erroneously) describing a position taken by the examiner.”  In fact, as long as the BPAI clarified that it wasn’t relying on this “erroneous” characterization by the patent examiner of what Gonzalez taught, that would have been “harmless error.”

But the Federal Circuit gagged on treating the BPAI’s second and third statements as “harmless error,” as was urged by the USPTO.  Regarding the BPAI’s second statement, the USPTO agreed that the patent applicant (not the BPAI) correctly read Gonzalez as teaching that the polymer was attached to either the light or the heavy chain, and thus wasn’t linking the light and heavy chains.  That meant that the patent applicant’s “use of a polymer to link together two F(ab’) fragments may be less likely to be obvious.”  Regarding the BPAI’s third statement, the USPTO conceded that “Gonzalez teaches six different possible antibody fragments” and thus more than the three antibody fragments suggested by this third statement.  That meant that the BPAI “did not appreciate the full scope of antibody fragments disclosed in Gonzalez,” and therefore the Federal Circuit couldn’t “be confident about [the BPAI’s] ultimate conclusion that the selection of one of them to form [the patent applicant’s] molecule is obvious.”

Because the Federal Circuit couldn’t say “with confidence that the [BPAI] would have reached the same conclusion in the absence of these errors, we are persuaded they are indeed harmful.”  In other words, this was not a situation where the USPTO’s “path, though convoluted, can be discerned,” citing the 2002 Federal Circuit case of In re Huston.

As observed by the Federal Circuit at the end of Chapman, the BPAI on remand was “in no way precluded from, and indeed may be correct in, finding the claims to be obvious, particularly in the light of Gonzalez’s disclosure of joining two antibody fragments together with a polymer to make a dumbbell-shaped structure.”  But what is refreshing and important in the Federal Circuit’s opinion is that mischaracterizations of references relied upon by the patent examiner (or the BPAI) for obviousness rulings are not to be simply glossed over as “harmless error.”  Put differently, the Chapman decision gives patent applicant’s a viable legal basis to hold a patent examiner’s (as well as the BPAI’s) “feet to the fire” to challenge an obviousness (or anticipation) rejection based on one or more mischaracterizations of a reference.

*© 2010 Eric W. Guttag.


Warning & Disclaimer: The pages, articles and comments on IPWatchdog.com do not constitute legal advice, nor do they create any attorney-client relationship. The articles published express the personal opinion and views of the author as of the time of publication and should not be attributed to the author’s employer, clients or the sponsors of IPWatchdog.com. Read more.

Join the Discussion

18 comments so far.

  • [Avatar for EG]
    March 1, 2010 05:05 pm

    Gene, SB and NAL,

    I just posted my rebuttal on Patent Docs. I don’t mind folks disagreeing with me; I may learn something from the debate that changes my mind. But try to advance the debate, instead of making snide remarks or “parodying” what I said.

  • [Avatar for EG]
    March 1, 2010 12:32 pm

    Gene, SB and NAL,

    Deja vu. Take a look at what 6 said about my comment in response to Kevin Noonan’s analysis (quite good) of Chapman on Patent Docs. In nothing else, 6 remains consistent and incorrigible.

  • [Avatar for EG]
    March 1, 2010 12:27 pm

    “Personally I am saddened that Crouch’s once good blog has become the land of the flame fest.”

    I likewise. Dennis on Patently-O often has some very thought provoking IP subjects which deserve some considered comments and opinions. As much as I hate to admit, even MM and 6 sometime come up with a lucid response. But those “lucid responses” are drowned by all the banalities and snarkiness these folks (and others) spew forth. Again, we can disagree without being disagreeable (which MM, 6 and some others are).

    NAL: I saw what endured almost single-handly on Patently-O. It really gets brutal (and non-productive) over there at time. There’s also no way 6 would make it as a patent attorney; he would be “torched” by any respectable IP firm with his attitude. I also wonder how MM can make it as a patent attorney with the attitude he has about patent law practice (there are other or former patent attorneys like Steve Kinsella who share MM’s almost pathological disdain for the US patent system). My theory: MM is “independently wealthy” so that his patent practice (if you can call it that) is really a hobby, not a career. Just a theory which could be totally wrong.

  • [Avatar for Noise above Law]
    Noise above Law
    February 27, 2010 07:55 am

    My aoplogies for diminishing this thread with the snippet of a 6ism, Those wishing to save some brain cells from being exposed, please stop here.

    Ah, this is the caliber that this blog passes up when it decides to ban the nonsense of 6:

    I posted “Not as cute a story as on IPWatchdog, but the same simple answers.” to a similar Trainwreck story as Gene’s Sue D. Nym story.

    6, under a weak sockpuppet replied:
    “Bull Shiot. Dennis roolz, Gene Quinn droolz. (NAL is teh foolz)”

  • [Avatar for step back]
    step back
    February 26, 2010 10:20 pm


    “Teach” and “disclose” are two distinct actions. When a reference allegedly “teaches” something, the examiner is asserting that it teaches function as well as form. To grab merely the form while ignoring the taught function is to ignore what the reference “fairly teaches” to one of ordinary skill. There is some CAFC or CCPA case out there that talks about that. Sorry, I don’t have the citation at hand.

  • [Avatar for Ted Weisz]
    Ted Weisz
    February 26, 2010 05:48 pm

    This whole discussion is very relevant to an office action that I am responding to right now. The Examiner keeps on taking each element from each claim, copies it, then makes the statement that reference X teaches this element and points to a column and line number. The problem is that the cited portion of the reference has absolutely nothing to do with the claim element. He has done this for 14 pages.

  • [Avatar for Noise above Law]
    Noise above Law
    February 26, 2010 05:38 pm

    step back,

    I will contritely admit my part in the flame fest at the Trainwreck. It does burn me so to see the utter inanities put forth on such a widely read forum for patent law with no one seemingly caring to refute the pure garbage. I do recognize that the antagonists have a shameless lack of care about the law – they really don’t care how wrong they are, nor how banal or crass they can be.

    However, there are times when I simply enjoy getting muddy. Getting the best of the straw and rope tag team can be somewhat of a sport. Leaving them speachless and unable to give answers other than trying to twist my words appeals to the slightly sadistic side of me – better to excise that with the appropriate crowd.

    Gene’s move to ban 6 from this thread due to the dangerous level of his incompetence was indeed a wise move – it may hurt the ratings, but the corresponding lack of true intellectual discussion is worth the sacrifice.

    I do tend to limit my involvement here, less I bring some inadvertent snark. I try to bring a different brand of trouble here with playful antagonism.

    I have recognized real intellectual growth of several posters here – notably “pop” and it does make me smile.

  • [Avatar for step back]
    step back
    February 26, 2010 05:10 pm


    One way to keep MM and fellow trolls away from Gene’s blog is to keep feeding them over there, at Dennis’s blog, to the point of indigestion. (Can I patent such a method?)

    Personally I am saddened that Crouch’s once good blog has become the land of the flame fest.

  • [Avatar for EG]
    February 26, 2010 05:01 pm

    SB and NAL,

    Glad to see you both commenting on this thread. And I’m thankful that MM and 6 are staying far, far away. I really had to bite my tongue on Patently-O with respect to MM’s snarky comments about what I said about the Chapman case. But as my brother said, arguing with MM is like wreslting with a muddy pig: you only get dirty doing so.

  • [Avatar for step back]
    step back
    February 26, 2010 02:41 pm


    Them thinking me is you? Won’t happen. I can never rise up to your gold standard. 😉

    Re new count system, I have heard rumor that examiners are trying to do quicky allowances over the phone because of new count system. Anyone else hear that? (Will look forward to reading your new post Gene, on the new count system. Can’t say that I yet understand it and how it will be played out. Is RCE no longer the path to double digit points?)

  • [Avatar for Noise above Law]
    Noise above Law
    February 26, 2010 01:43 pm

    “But hey, since when has the law been an impediment to the PTO’s mission accomplished goal: reject, reject, reject?”

    Careful step back, someone will accuse you of being me.

    Oh wait, this is not the Trainwreck.


  • [Avatar for Gene Quinn]
    Gene Quinn
    February 26, 2010 01:00 pm


    It will be interesting to see if examiners continue on the reject, reject, reject path given that under the new count system they can do less work and get more credit by issuing patents quickly.


  • [Avatar for EG]
    February 26, 2010 12:55 pm


    Ah, now I understand the story behind this nonsense. Not only is it impermissilbe use of applicant’s disclosure but also contrary to 37 CFR 1.104(c)(2) which requires the pertinence of the reference to be pointed out with particularity; simply citing a long passage from the reference doesn’t cut it.

  • [Avatar for step back]
    step back
    February 26, 2010 12:16 pm

    “I’ve had instances where they [the Examiners] simply quote what’s in the claim (sometimes word for word) [when making a 103 obviousness rejection]”


    That is no coincidence.
    It’s a technique taught to newbie examiners in some Patent Academy sessions. They call it “claim mapping”. Of course from a legal stand point it is another name for the impermissible use of applicant’s disclosure as a blueprint. But hey, since when has the law been an impediment to the PTO’s mission accomplished goal: reject, reject, reject?

  • [Avatar for EG]
    February 26, 2010 11:17 am

    “I guess I will have to start citing Chapman in such situations.”


    As will I. One of the most hiliarious instances of mischaracterization of a reference I’ve experienced was a patent examiner who relied upon a drawing in a patent reference which appeared, at first blush, to be similar to a drawing in the patent application I was prosecuting. The problem was that each of the drawings represented entirely different and unrelated concepts, especially once you compared the text of the reference patent to the text in the patent application. Fortunately, the patent examiner got my “gentle hint” in my response that the reference drawing wasn’t as relevant as he thought it was, and dropped the rejection based on that drawing.

  • [Avatar for Ted Weisz]
    Ted Weisz
    February 26, 2010 09:18 am

    I find this problem has become very common in recent years. Very often it appears that the Examiners do not read even a substantial portion of a reference they are citing but, instead, they perform a universal search using some key words and then just cite the paragraphs containing the words, whether relevant or not. Moreover, I also find that once an Examiner takes an erroneous position on what the prior art discloses, this position is almost impossible to shake. I guess I will have to start citing CHapman in such situations.

  • [Avatar for EG]
    February 26, 2010 07:55 am


    Thanks for your comments. You could be right that non-biotech’s may be intimidated by the subject matter of Chapman. That’s why I spent some verbiage describing what the invention related to (including using a key figure from the case).

    There’s definitely a few “take aways” in Chapman. My main point is that Chapman reaffirms after KSR (and its “common sense” nonsense) that the patent examiner (as well as BPAI) must characterize the references relied upon fairly (and accurately), or the obviousness ruling based on those references is inherently suspect. Put differently, the evidence relied upon does matter to the outcome.

    All too often, I’ve had patent examiners who make you try to guess what the reference fairly teaches. For example, I’ve had instances where they simply quote what’s in the claim (sometimes word for word) and then cite some passage in a reference that allegedly corresponds without ever identifying where the the specific claim elements are present in that passage. Another examiner favorite is to rely upon so much of the reference as supports the rejection, but then ignore other portions of the reference which teach away.

  • [Avatar for step back]
    step back
    February 26, 2010 06:57 am

    Hi Eric,

    Thanks for your article.
    Too bad Chapman was a biotech case.
    That means many won’t read it.
    They’ll be intimidated by the incomprehensible (to non-bio’s) bio talk.

    The main points to take away from Chapman is focus on a few key phrases and words:

    1. substantial evidence rule
    2. “teaches” is not same as “discloses”
    3. likelihood of what is taught or suggested and likelihood of it being followed
    4. facts “found” by the examiner/Board
    5. harmless error rule