Appeal No. 2006-0352 Παγε 2
Application No. 09/929,546
BACKGROUND
“PSMA is an integral membrane protein known to have a short intracellular tail
and a long extracellular domain.” Specification, page 8. Various researchers have
reported that “PSMA is prostate-specific and shows increased expression levels in
metastatic sites and in hormone-refractory states” (id.); that “PSMA is more strongly
expressed in prostate cancer cells relative to cells from the normal prostate or from a
prostate with benign hyperplasia” (id.); and that “PSMA is not found in serum” (id.). On
the other hand, according to appellant, “the vascular endothelial cells supplying blood to
cancerous tissues . . . express an extracellular domain of [PSMA], irrespective of the
type of cancer involved . . . [while] vascular endothelial cells supplying blood to normal
tissues do not express an extracellular domain of [PSMA]” (id., page 17).
In any case, according to appellant, PSMA is “an attractive target for antibody
mediated . . . imaging and therapy of [ ] cancer” (id., page 8). However, “antibody
molecules do not, under normal circumstances, cross the cell membrane unless they
bind to the extracellular portion of a molecule and become translocated intracellularly,”
thus antibodies that bind the intracellular portion of PSMA “do[ ] not have access to [the]
antigenic target site in . . . viable cell[s]” and will only bind cells that are already dead
(id., page 9).
The present invention is directed to methods of treating cancer using “biological
agents,” in this case, polyclonal or monoclonal antibodies which bind the extracellular
domain of PSMA. Appellant describes four “particularly preferred” biological agents,
monoclonal antibodies E99, J415, J533 and J591, to be “used alone or as a component
in a mixture with other antibodies or other biological agents” (id., page 24). “In a
particularly preferred embodiment . . . a first biological agent is conjugated with a
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Last modified: November 3, 2007