Appeal No. 2005-2690
Application No. 09/935,442
comprising fibrin for the treatment of restenosis and stent thrombosis.
According to the procedure of Dinh a stent is prepared by first polymerizing
fibrin in a molded cavity, in which the shape of the cavity defines the shape
of a fibrin stent. ....
Dinh does not teach the claimed activator and precursor in their
medical device. ....
Delmotte et al teaches a fibrin delivery device and a method of
forming fibrin on a wound surface to control bleeding and tissue sealing.
The device of Delmotte comprises a first and second biochemically reactive
liquid, comprising fibrinogen and thrombin respectively, in separate
containers. The two liquids are in communication with a spray unit, capable
of atomizing both liquids, when sprayed on the wound surface. Fibrinogen
and thrombin, upon spraying, forms fibrin glue (a barrier material) at the
surface of the wound (col. 3, lines 11-67). ... According to the invention of
Delmotte, the polymerization of fibrin occurs only at the site of
administration. ... Delmotte fails to suggest coating a stent.
We do not find that the examiner has provided sufficient evidence to support a
prima facie case of obviousness. We do not find the evidence would have provided one
of ordinary skill in the art with sufficient motivation to substitute a separately released
fibrinogen and thrombin for conversion to an activated fibrin form for local delivery, for
the fibrin coating in the vascular stent of Dinh. In particular, we do not find where the
examiner has indicated, or where the references disclose, that separately released
fibrinogen and thrombin for conversion to an activated fibrin form for local delivery, can
be incorporated into or adapted to a medical device, such as the vascular stent of Dinh.
As argued by appellant, Dinh teaches away from providing thrombin and
fibrinogen separately at the treatment site for in situ polymerization. Brief, page 6. Dinh
states that “[p]referably the coagulating effect of any residual coagulation protein in the
fibrin should be neutralized before employing it in the stent ... in order to prevent clotting
at the fibrin interface with blood after stent implantation.” Col. 5, lines 7-11.
In addition, appellant argues (Brief, page 7) that Delmotte
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