Appeal No. 1997-3542
Application No. 08/192,507
indicating that antibodies against surface immunoglobulins, such as IgM, cause antibody
bound surface IgG molecules to cap and then be internalized.
It would appear from Lambert that certain antibody-toxin conjugates to human
lymphoid cell surface antigens are known in the prior art. It would appear from Julius and
Kung that anti-IgM antibodies having the claimed properties are also known in the prior
art. The question then becomes whether the examiner has established a factual basis
providing a reason, suggestion or motivation for using the known antibodies to form the
claimed antibody-toxin conjugates, and whether one of ordinary skill in the art would have
had an expectation of success that the antibody-toxin conjugates would function as
claimed.
It is the examiner’s position that [Answer, page 11]:
[i]t would have been prima facie obvious to one of ordinary skill in the
art at the time the invention was made to combine the teachings of the cited
prior art and to conjugate the anti-IgM monoclonal antibodies taught by
Kung et al. and Julius et al. according to the methods of Lambert et al. One
of ordinary skill in the art would have been motivated to do so in view of the
teaching of Lambert et al., that immunotoxins comprising monoclonal
antibodies specific for surface markers on lymphoid cells conjugated to
cytotoxic moieties such as gelonin and PAP were considered to be useful
for in vitro assays in order to examining [sic, examine] the effect of various
parameters on cytotoxicity of immunotoxins in order to determine how to
improve the efficacy of immunotoxins.
One of ordinary skill in the art would have expected that anti-IgM
immunotoxins would be internalized after binding IgM molecules on the
surface of a B cell and once internalized, to exhibit toxicity as did the
immunotoxins made by Lambert, et al.
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