Ex parte Yang

Board of Patent Appeals and Interferences

Apr 28, 2000

07912122 (B.P.A.I. Apr. 28, 2000)

1
THIS OPINION WAS NOT WRITTEN FOR PUBLICATION
The opinion in support of the decision being entered today (1) was not written for
publication in a law journal and (2) is not binding precedent of the Board.
Paper No. 25
UNITED STATES PATENT AND TRADEMARK OFFICE
__________
BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
__________
Ex parte ZHI YANG
__________
Appeal No. 1996-1916
Application 07/912,122
__________
ON BRIEF
__________
Before WINTERS, WILLIAM F. SMITH and SCHEINER, Administrative Patent Judges.
SCHEINER, Administrative Patent Judge.
DECISION ON APPEAL
This is an appeal under 35 U.S.C. § 134 from the final rejection of claims
1 through 4 and 7, all the claims pending in the application. Claims 1 and 7 are
representative of the subject matter on appeal and read as follows:
1. A cDNA sequence (SEQ ID NO:3) encoding soluble Flk-2.
7. Soluble Flk-2 (SEQ ID NO:4) as a purified composition.
Appeal No. 1996-1916
Application 07/912,122
U.S. Patent No. 5,185,438 to Lemischka. See column 3, lines 48-60. 1
2
The reference relied on by the examiner is:
Lemischka 5,185,438 Feb. 9, 1993
Claims 1 through 4 and 7 stand rejected under 35 U.S.C. § 112, first paragraph as
based on a non-enabling disclosure. In addition, claims 1 through 3 stand rejected under
35 U.S.C. § 103. As evidence of obviousness, the examiner relies on Lemischka. We
reverse both rejections.
DISCUSSION
Enablement
Flk-2 is a tyrosine kinase and “putative stem cell growth factor receptor” with a
ligand-binding extracellular domain, a transmembrane domain, and an intracellular
catalytic domain. The present invention is directed to a 1.9 kb cDNA molecule identical to1
portions of the 3.4 kb cDNA molecule encoding murine Flk-2; an expression cassette
containing the 1.9 kb cDNA molecule; and a vector containing the cassette (claims
1 through 3). The invention further encompasses the protein encoded by the 1.9 kb cDNA
molecule, and a method of producing the protein (claims 4 and 7). The 1.9 kb cDNA
transcript appears to be “an alternative spliced form of [Flk-2]" which “lacks the
transmembrane sequence as well as portions of the extracellular and intra-cellular
Appeal No. 1996-1916
Application 07/912,122
3
sequences” of the 3.4 kb cDNA transcript, and appellant concludes that the 1.9 kb
transcript encodes a secreted, soluble form of Flk-2 (specification, pages 2 and 9).
Soluble Flk-2 lacks 59% of the extracellular domain of the Flk-2 transmembrane receptor,
thus, the examiner considers it to be “extremely unpredictable that an extracellular domain
consisting of only 41% of the previously known receptor would retain ligand binding
function” or “be able to achieve a conformation such as to form structures necessary for
antibody recognition.” Further, the examiner believes “[i]n the absence of any structural or
functional characterization of the encoded protein, it would require undue experimentation
to use the claimed DNA to make protein, make antibodies to that protein, determine the
individual specificities of all such antibodies, and then determine how to use such based
upon those specificities.” Accordingly, claims 1 through 4 and 7 stand rejected under 35
U.S.C. § 112, first paragraph, as the specification “does not enable how to use the
claimed DNA or protein.” Examiner’s Answer, page 4.
It is well settled that the specification need only teach one skilled in the art how to
make and use the claimed invention, and that it is the examiner’s initial burden to provide
reasons why a supporting disclosure does not enable a claim. As stated in
In re Marzocchi, 439 F.2d 220, 223, 169 USPQ 367, 369-70 (CCPA 1971):
[A] specification disclosure which contains a teaching of the manner and
process of making and using the invention in terms which correspond in
scope to those used in describing and defining the subject matter sought to
be patented must be taken as in compliance with the enabling requirement
Appeal No. 1996-1916
Application 07/912,122
4
of the first paragraph of § 112 unless there is reason to doubt the objective
truth of the statements contained therein which must be relied on for enabling
support.
In this case, the specification teaches a number of uses for the claimed DNA and
protein (pages 3 and 6):
Nucleic acid encoding [Flk-2] may be obtained from host hematopoietic
stem cells by using as a probe, at least twelve, usually at least eighteen,
nucleotides of the subject sequence. The subject sequence, which is the
mouse sequence, may be used to identify other mammalian analogs by
hybridiz[ation] . . .
The cDNA may be used for expression of the [Flk-2] in any convenient
expression host . . .

* * *
The subject proteins find use in culture and in vivo in competing with Flk-2
receptor for Flk-2 ligand. Thus, the subject compositions may be used for
modulating the growth of hematopoietic progenitor cells. In addition, the
subject proteins or fragments thereof of at least about 12 amino acids . . .
may be used for the production of antibodies . . . Particularly, the soluble Flk-
2 may be used to produce antibodies which are specific for the juncture or
sequences proximal to the juncture between about amino acids 680 and 700
. . . The antibodies may be used for identifying cells carrying Flk-2, removing
soluble Flk-2 from culture fluids or natural fluids, purifying Flk-2, and the like.
The antibodies may also be used for assaying for the presence of Flk-2.

Thus, the dispositive issue is whether the examiner has met the initial burden of
establishing a reasonable basis to doubt the objective truth of statements in the
specification regarding the use of the claimed DNA and protein.
As further stated in In re Marzocchi, 439 F.2d 220, 224, 169 USPQ 367, 370
(CCPA 1971):
Appeal No. 1996-1916
Application 07/912,122
5
[I]t is incumbent upon the Patent Office, whenever a rejection on this basis is
made, to explain why it doubts the truth or accuracy of any statement in a
supporting disclosure and to back up assertions of its own with acceptable
evidence or reasoning which is inconsistent with the contested statement.

In our judgment, a mere assertion of unpredictability is insufficient ground for
questioning the truth or accuracy of appellant’s disclosure, or for shifting the burden to
appellant to provide rebuttal evidence substantiating statements made in the specification.
To the extent that the examiner argues that appellant’s disclosure does not enable
any person skilled in the art to make and use the claimed invention without undue
experimentation, we disagree. Given the straightforward, routine protocol outlined in the
specification, together with what is well known in the art, we are persuaded that any
experimentation necessary to practice the claimed invention would be routine, not undue.
We hold that the examiner has not set forth a reasonable basis for questioning the
enablement of the claims on appeal. Accordingly, the rejection of claims 1 through 4 and 7
is reversed.
Obviousness
Claim 1 is directed to cDNA of a particular sequence (SEQ ID NO:3) encoding
soluble Flk-2. Claim 2 is directed to an expression cassette comprising cDNA (SEQ ID
NO:3) encoding soluble Flk-2; claim 3 is directed to a vector containing the expression
Appeal No. 1996-1916
Application 07/912,122
6
cassette of claim 2. Claims 1 through 3 stand rejected under 35 U.S.C. § 103 as
unpatentable over Lemischka.
Lemischka discloses DNA encoding Flk-2, a 992 amino acid “receptor protein
tyrosine kinase” with a ligand-binding extracellular domain, a transmembrane domain, and
an intracellular catalytic domain (column 3, lines 48-60). The reference also discloses a
form of Flk-2 lacking the transmembrane region (amino acids 545-564), the catalytic
domain (amino acids 565-992), and a portion of the extracellular domain (amino acids 1-
27); i.e., a form of Flk-2 corresponding to amino acids 28-544 of the 992 amino acid
receptor (column 3, lines 48-56 and column 6, lines 15-20). The presently claimed cDNA,
on the other hand, has a sequence identical to the Flk-2 receptor, but for “a 511 amino
acid deletion beginning with the amino acid 221 Val and ending with the 731 Gln, so that
the Lys at 220 is joined to the Ala at 732" (specification, pages 2 and 9).
The examiner argues that “there is no sequence with which the claimed DNA would
hybridize that would not also hybridize to the DNA as disclosed by Lemischka” and
concludes that “the claimed DNA is, with respect to its use as hybridization probe,
functionally equivalent to and therefore prima facie obvious over the DNA disclosed by
Lemischka” (Examiner’s Answer, page 6).
We find ourselves in agreement with appellant that “[t]his is not the standard for
obviousness” (Reply Brief, page 2). As argued by appellant, the claimed cDNA “has a
Appeal No. 1996-1916
Application 07/912,122
7
specific deletion in the transmembrane region, as well as portions of the extracellular and
intracellular sequences” (Id., page 3). The examiner concedes that Lemischka “does not
disclose the particularly claimed sequence,” but does not provide reasons why one of
ordinary skill in the art would have found it obvious to modify the prior art sequence to
arrive at the specifically claimed cDNA (Examiner’s Answer, page 6).
35 U.S.C. § 103 requires that obviousness be determined on the basis of the
claimed “subject matter as a whole.” Where, as here, the determination of obviousness is
based on less than the entire claimed subject matter, the examiner’s conclusion of
obviousness cannot be sustained. Accordingly, we find that the examiner’s initial
Appeal No. 1996-1916
Application 07/912,122
8
urden of establishing a prima facie case of obviousness has not been met, and the
rejection of claims 1 through 3 under 35 U.S.C. § 103 is reversed.
REVERSED
)
Sherman D. Winters )
Administrative Patent Judge )
)
)
) BOARD OF PATENT
William F. Smith )
Administrative Patent Judge ) APPEALS AND
)
) INTERFERENCES
)
Toni R. Scheiner )
Administrative Patent Judge )
TRS/cam
Appeal No. 1996-1916
Application 07/912,122
9
Pamela Sherwood, PhD.
Bozicevic and Reed
285 Hamilton Avenue
Suite 200
Palo Alto, CA 94301