Appeal 2007-1633
Application 09/480,236
immunotoxin. Specifically, that people do not have a pre-existing antibody
titer that could inhibit or alter the efficacy of a PE based immunotoxin.
Further, while Appellants direct attention to Batra to support their
assertion that DT and PE based immunotoxins may exhibit different
activities on different cell lines, Appellants appear to miss Batra’s clear
teaching that while the DT based immunotoxin was about threefold more
active than a PE based immunotoxin on some cell lines, in no case was the
DT based immunotoxin much more active (e.g., at least 100-fold) than the
PE based immunotoxin, “whereas the reverse was observed” (Batra,
bridging paragraph, pages 2203-2204). In addition, Batra states that
active single-chain immunotoxins can be made with different
toxin moieties . . . . With this information in hand, it should be
possible to make active single-chain immunotoxins from the
wide variety of toxins (plant, bacterial, and animal) that are now
being made by chemical coupling methods . . . .
(Batra, 2204, col. 2, last paragraph.) Stated differently, notwithstanding
Appellants’ assertion to the contrary, Batra teaches that immunotoxins can
be made from a wide variety of toxins. No doubt these immunotoxins may
exhibit different activities relative to each other, but Appellants’ claimed
invention does not require any particular activity other than having ADP-
ribosylating and translocation functions but substantially diminished cell-
binding ability. As discussed above, the prior art of record teaches DT and
PE based immunotoxins wherein both the DT and PE components have
ADP-ribosylating and translocation functions but substantially diminished
cell-binding ability.
Based on the teaching of the prior art relied upon by the Examiner, we
find that it would have been prima facie obvious to a person of ordinary skill
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