Appeal No. 95-4691
Application 08/021,652
1997); In re Zletz, 893 F.2d 319, 321-22, 13 USPQ2d 1320, 1322 (Fed. Cir. 1989). We are of the
view that appellants’ claims encompass only a tissue type plasminogen activator (t-PA) or a derivative
thereof. Appellants point out at page 1, lines 12-16 of the specification that “t-PA has become the object
of such attention as a novel plasminogen activator for pharmaceutical use, because, unlike conventionally
known urokinase, t-PA has strong affinity to fibrin and high thrombolytic activity and, in particular, single-
chain t-PA cause fewer side effects.” In the brief, appellants state that “urokinase is an entirely different
protein from t-PA” (brief: p. 11). While the scope of the claim as to the derivatives of t-PA is uncertain
and the subject of a new ground of rejection under the provisions of 37 CFR § 1.196(b), infra, we find
a person having ordinary skill in the art would have considered appellants’ claims are limited to tissue type
plasminogen activators and would not include other plasminogen activators such as urokinase.
The Duffy and Isaacs patents disclose enhancing the solubility of a t-PA by combining a citrate salt
and an amine such as an arginine salt with t-PA. EP 198321 discloses a pharmaceutical drug consisting
of t-PA and a polysulfate ester of a saccharide for the treatment of thromboses and emboli. According to
the patentee, “[i]t has surprisingly been found that [tissue] ... plasminogen activators ... have a high affinity
for polysulfate esters of saccharides ... and that the activity of PA is balanced in the presence of a
polysulfate ester of a saccharide ...” (translation, p. 2). Dussourdd’Hinterland discloses a pharmaceutical
composition comprising a urokinase, plasminogen activator, and an anionic polymer such as polysaccharide
sulphate (dextran). Neither EP 198321 nor Dussourdd’Hinterland teach or suggest adding an amine to
the plasminogen activator composition. According to the examiner:
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