Appeal 2007-1633
Application 09/480,236
scope of Appellants’ claimed invention include PE40 (id.) and PE38
(Specification 25).
The Examiner finds that Neville teaches a recombinant immunotoxin
polypeptide comprising an anti-human CD3-binding domain and the ADP-
ribosylating exotoxin diphtheria toxin (DT) (Answer 6). The Examiner finds
that Neville does not teach a recombinant immunotoxin polypeptide
comprising a PE mutant (Answer 7). To make up for this deficiency, the
Examiner relies on Kreitman ’95 and Kreitman ’94.
The Examiner finds that Kreitman ’95 teaches an immunotoxic
antibody comprising a PE mutant (PE38 and PE40) (id.). In addition, the
Examiner finds that Kreitman ’94 teaches an immunotoxic antibody
comprising a PE mutant (PE40) (id.).
Based on this evidence, the Examiner concludes that it would have
been prima facie obvious to substitute a PE mutant for the diphtheria toxin
component of Neville’s recombinant immunotoxin polypeptide (Answer 7-
8).
In response, Appellants assert that “[a]lthough the bits and pieces of
Appellants’ claimed immunotoxin may be present in the prior art, the
requisite incentive or motivation to combine these bits and pieces is lacking”
(Br. 11). In this regard, Appellants assert that Kreitman ’94 fails to teach the
interchangeability of PE mutants with DT in immunotoxins (id.). Instead,
Appellants point out that Kreitman ’94 “[c]ompares the activities of several
immunotoxins directed against Tac (not CD3 as presently claimed). The
data in Tables 3 and 4 of the reference show the ability of different
patients[’] blood cells to be killed by the different immunotoxins. There is
no predictability or pattern to the results” (id.). Therefore, Appellants assert
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