Executive summary
US Patent 6,960,352 claims US methods for tumor or hyperplastic-tissue treatment by locally inducing platelet thrombus using a solid-phase platelet-binding agent based on mammalian or recombinant von Willebrand factor (VWF), including device/platform embodiments (particles, coils, stents) and localization via targeting moieties and catheter/placement delivery. The claim set is broad on (i) indication class (vascularized tumor/hyperplastic tissue), (ii) thrombus mechanism (platelet capture via VWF immobilized on a solid support leading to in vivo thrombosis), and (iii) substrate/platform and attachment chemistry (many materials, direct/indirect/covalent/non-covalent binding with spacers). In parallel, the claim set is also granular on device forms and particle size, which creates identifiable infringement “entry points” for competitors using VWF-coated embolic, thrombogenic, or platelet-capture platforms at or near tumors. The practical risk for generic-style “non-therapeutic” replication is low because this is a method-and-platform IP estate, not a small-molecule composition. The principal freedom-to-operate (FTO) exposure concentrates in local intra-tumoral or perivascular administration of a VWF-based platelet-capture solid support that is intended to form thrombus to limit blood supply.
How do claims 1–52 define the core invention in US Patent 6,960,352?
Core claim thesis (independent claim 1; dependent variants 2–52):
A method for treating a vascularized tumor or hyperplastic tissue by (1) administering at a predetermined site a solid-phase agent bearing a platelet-binding agent selected from mammalian VWF or recombinant VWF, and (2) subsequently inducing thrombus in vivo by capturing platelets via immobilized VWF, activating platelets, and allowing a thrombus to form at that site, thereby limiting blood supply and treating the tissue.
Independent claim 19 is parallel but focuses on delivery of “VWF bound to solid support,” with the key functional steps being platelet capture and thrombus formation.
Independent claim 20 specifies a particular immobilization format: VWF coated on macro-aggregated albumin to create immobilized VWF delivered to a site to capture and activate platelets.
Key infringement-relevant elements that must align in an accused method:
- Treatment target category: “vascularized tumor or hyperplastic tissue” (not ischemic tissues generally).
- Delivery locus: “predetermined site” at or near the tumor/hyperplastic tissue.
- Agent format: a solid-phase agent (explicitly includes particles, coils, stents; broadly includes “solid support” and embedded binding agent).
- Platelet-binding mechanism: platelet capture depends on VWF immobilized on or within the solid phase agent.
- Functional thrombus outcome: in vivo thrombus formation by platelet activation and thrombus formation at the site.
- Intended vascular occlusion effect: limiting blood supply at the site is part of the claimed method’s therapeutic mechanism.
What patents protect local tumor thrombus induction using immobilized VWF solid-phase agents?
US 6,960,352 is the centerpiece for this specific VWF-on-solid-support thrombogenic mechanism in the tumor/hyperplasia indication space. Based on the claim content itself, the estate is organized around:
- VWF as the platelet-binding ligand (mammalian and recombinant).
- Solid-phase carriers spanning polymeric particles and implantables (coil, stent) and biologic carriers (albumin aggregates).
- Capture and activation sequence leading to thrombus.
- Targeting moieties directing the solid-phase agent to antigens on target vasculature.
- Attachment architecture (direct/indirect, spacer chemistries, covalent/non-covalent).
Claim breadth implies that other “VWF solid support” patents in the same family cluster likely exist (not determinable from the prompt alone) covering:
- VWF immobilization chemistry and spacer architectures,
- specific carrier materials and particle size windows,
- catheter-based deployment and device coatings.
Actionable enforcement logic: If another patent claims a different VWF carrier chemistry but still lands on “VWF bound to solid support that captures/activates platelets to form thrombus at a predetermined site near a tumor,” it will overlap heavily with the method scaffolding in claim 1/19/20. If a competitor uses a different ligand than VWF (eg, platelet-binding antibodies to GP receptors or fibrin-based thrombosis triggers), they may avoid direct claim 1’s “binding agent selected from mammalian VWF and recombinant VWF” requirement.
Which claim elements create the highest infringement risk for competitors?
1) The VWF immobilized on or within a solid-phase carrier
The claim repeatedly requires VWF selected from mammalian or recombinant and immobilized on or within the solid-phase agent. This excludes formats where VWF is fully soluble and systemically administered without immobilization, and it excludes solid carriers that do not function through VWF-mediated platelet capture/activation.
2) In vivo thrombus formation as the mechanism
Claims require subsequent inducing a thrombus in vivo with captured and activated platelets forming a thrombus at the site. An accused therapy that causes platelet activation indirectly without VWF capture, or that relies on different coagulation pathways not tied to VWF capture/activation on the solid support, is at higher risk of non-infringement.
3) “At or near a vascularized tumor or hyperplastic tissue”
Generalized anti-angiogenic therapy or systemic coagulation modulation without a predetermined local site is outside the language.
4) Local targeting moieties tied to antigens on target vasculature
Claims 7–10 and 8 specify targeting moieties directed to antigens on target vasculature. Using non-targeted deployment may still fall within claims 1, 19, 20, but could avoid narrower dependent claim coverage.
What is claimed about solid carriers: particles, coils, and stents?
Particles (claims 2, 11–13, 21, 25–38)
- Claim 2: solid-phase agent is a particle.
- Particle size carve-outs (dependent):
- 8 to 7000 microns (claim 11)
- 8 to 150 microns (claim 12)
- 200 to 1000 microns (claim 13)
- Claim 25: particle is formed of material capable of retaining vWF.
- Claim 26 onward enumerates very broad material lists (polymers, proteins, polysaccharides, nanoparticles, cells, albumin aggregates, liposomes, etc.).
- Claim 37–43 cover binding architecture:
- VWF bound on or within the solid-phase agent,
- direct vs indirect binding,
- covalent vs non-covalent binding,
- use of spacers including peptide, antibody/fragment, fusion protein, carbohydrate,
- Fc portion spacers are specifically called out.
Coils (claims 3, 14, 23)
- Claim 3: solid-phase agent is a coil.
- Claim 14: coil is coated with VWF.
- Claim 23: administering includes catheter/microcatheter/syringe/procedure/manual placement.
Stents (claims 4, 15, 24)
- Claim 4: solid-phase agent is a stent.
- Claim 15: stent is coated with VWF.
- Claim 24: administering includes catheter/microcatheter/syringe/procedure/manual placement.
Implication for competitive FTO: A competitor’s risk is not confined to particulate embolics. If the platform is a coil or stent with VWF coating and a method of treating a vascularized tumor/hyperplasia by inducing thrombus, the method map still lands inside the core independent claims and corresponding dependent device claims.
Which VWF sources are claimed: human, porcine, autologous, heterologous?
Source-of-VWF limitations embedded in dependent claims
- Claim 5: VWF is of human origin.
- Claim 6: VWF is of porcine origin.
- Claim 44: VWF source is autologous (mammal and source are the same).
- Claim 45: VWF source is heterologous.
- Claim 46–48 further tie human/porcine origin to mammal source relationships.
Risk gradient:
If a competitor uses a VWF source different from human/porcine or uses a non-mammalian analog, they could attempt to design around narrower dependent claims. But the independent claim 1’s ligand selection is “mammalian VWF” or “recombinant VWF,” which already captures a large portion of practical biologic sourcing (human and porcine both fall within mammalian VWF).
How do targeting moieties expand the claim scope?
Claims 7–10 (dependent) add a localization layer:
- Claim 7: solid-phase agent includes a targeting moiety.
- Claim 8: targeting moiety directed to an antigen(s) on target vasculature.
- Claim 10: targeting moiety includes biotin, peptides, human Fc fragments, a fusion protein, or combinations.
Claim 18 expands the taxonomy of targeting moieties:
- antibodies/fragments, ligands, receptors, hormone, lectin, cadherin, and binding fragments.
FTO note embedded in claim language:
Even if targeting moiety is not used, independent claim 1 is still written with no targeting requirement. Targeting moieties mainly increase coverage through dependent claims.
What is the role of biotin/avidin and spacer architectures?
Biotin/avidin dependent hooks (claim 9)
- Claim 9: solid-phase agent comprises biotin or avidin or derivatives.
Targeting moiety includes biotin and Fc formats (claim 10)
- Claim 10: includes biotin, peptides, human Fc fragments, fusion protein.
Attachment chemistry: direct vs indirect binding and spacers (claims 37–43)
- Direct covalent/non-covalent binding (claims 38–39).
- Indirect binding using spacers (claims 40–42).
- Spacer types include antibody or antibody fragment spacers and fusion protein spacers.
- Fc portion spacer (claim 43).
Competitive design-around pressure points:
If a competitor’s platform uses VWF immobilized through entirely different chemistry that is not direct/indirect via spacers as claimed, they may reduce dependent-claim overlap. But claim 1’s broad “binding agent capable of binding platelets” plus “binding agent selected from mammalian/recombinant VWF” and “solid-phase agent comprising” language makes it hard to escape capture by arguing only about attachment chemistry, unless immobilization is removed or VWF is replaced.
What tumor/hyperplasia localization and delivery modes are claimed?
Claims 21–24 list administration methods:
- catheter, microcatheter, needle, syringe,
- surgical procedure, or manual placement.
Claim 52 clarifies the site:
- organ or associated vasculature.
Practical effect:
This is drafted to cover both interventional radiology and surgical deployment. If a method uses endovascular delivery of VWF-coated embolics, coils, or stents near tumor vasculature, it aligns with the delivery language.
What formulation/product formats are explicitly claimed: macro-aggregated albumin?
Independent claim 20 is formulation-anchored:
- coating VWF on macro-aggregated albumin (immobilized VWF),
- delivering immobilized VWF to a pre-selected site near/on the tumor/hyperplastic tissue,
- enabling immobilized VWF to capture and activate platelets,
- producing thrombus to limit blood supply.
Dependent or related coverage implied by claim lists:
Claim 26 and other material lists include macro-aggregated and micro-aggregated albumin, and denatured protein aggregates, indicating the estate can also cover additional protein aggregate carriers beyond the explicit claim 20 embodiment.
How strong is the patent estate for different infringement theories?
1) Method-of-treatment infringement (claims 1, 19, 20)
These are broad. The essential limitation is VWF-mediated platelet capture and in vivo thrombus formation at a predetermined site near vascularized tumor/hyperplasia.
Strength signals from drafting:
- Mechanism-linked but not overly narrow on dosing regimens.
- Platform-flexible: “solid-phase agent,” explicitly particles/coils/stents.
- Carrier materials broadly enumerated as retaining vWF.
2) Device-platform-specific infringement (claims 2–4, 14–15)
Coil and stent coating claims can be strong leverage if a competitor uses VWF coatings on those devices.
Strength signals:
- Direct “further comprising coating” language for coils and stents.
3) Attachment-chemistry infringement (claims 37–43)
These dependent claims can tighten coverage, but enforcement typically depends on technical process evidence (how VWF is attached, spacer types, linkage). If a competitor attaches VWF without matching these dependent structures, they might still infringe independent claims if immobilized VWF is present and functions as claimed.
4) Particle size and material-set infringement (claims 11–13, 25–36)
These dependent claims can be strong if a competitor uses a conventional particle size window and standard polymer/protein carrier.
Caution:
If a competitor chooses radically different carriers or particle sizes, dependent claim coverage may narrow, but independent claims remain available.
What generic entry risks exist for a VWF thrombus-induction therapy?
This patent does not resemble a small-molecule “generic” scenario. The infringement risk is framed around method replication and platform equivalence:
- replacing VWF with a different platelet-binding ligand,
- using VWF but not immobilized on a solid support,
- using a solid support but not enabling VWF capture/activation-driven thrombus at the site,
- avoiding “at or near vascularized tumor/hyperplasia” localization (for example, systemic thrombosis control for different indications would not track the claim language).
If a competitor uses a VWF-on-solid platform for local thrombosis near tumors, the risk remains high even if dosing and device specifics differ.
When does US 6,960,352 lose exclusivity?
No filing, priority, maintenance, or expiration data was provided in the prompt. Without those facts, an exclusivity timeline cannot be stated as a complete and accurate analysis.
What litigation outcomes and Paragraph IV-style challenges are relevant?
No litigation, reexamination, IPR, or district court outcomes were provided. Without those facts, an accurate litigation-and-challenge timeline cannot be generated.
Regulatory pathway: what does FDA status imply for this patent?
No FDA product, NDA/BLA/IND details, Orange Book listings, or device classification were provided. A complete and accurate regulatory status analysis cannot be produced from the prompt.
How does US 6,960,352 compare with adjacent antithrombotic/anti-angiogenic IP?
Direct contrast created by claim language:
This patent is not an anticoagulation or anti-platelet mechanism patent. It claims inducing thrombus via platelet activation at a localized site using VWF immobilized to a solid carrier. That distinguishes it from:
- therapies aimed at preventing platelet adhesion/activation systemically,
- anti-VEGF angiogenesis inhibitors,
- embolic agents that occlude vessels without VWF-mediated platelet capture.
Practical competitor mapping:
The main “overlap zone” is with thrombogenic embolics and VWF- or von Willebrand-related platelet adhesion platforms used for local vascular occlusion in tumor contexts. Companies focused on purely mechanical occlusion (no platelet capture mechanism) may avoid the VWF-specific functional step if their therapy does not rely on immobilized VWF to capture/activate platelets.
Patent-claim operational map: what would an accused product/process need to look like?
Accused method checklist (based on claim text):
- Patient: mammal, including humans (claim 49 explicitly).
- Indication: vascularized tumor or hyperplastic tissue (claims 1, 19, 20, 52).
- Administration: to a predetermined site at or near the target tissue using catheter/microcatheter/needle/syringe/surgery/manual placement (claims 21–24).
- Solid support carrier: particle, coil, stent, or other solid support (claims 2–4, 37).
- Platelet-binding agent on/in carrier: mammalian or recombinant VWF immobilized on or within carrier (claims 1, 16, 37–40, 49–51).
- Functional mechanism: VWF captures platelets, induces activation, thrombus forms in vivo at site (claims 1, 19, 20).
- Optional enhancements: targeting moiety to antigens on target vasculature; biotin/avidin; spacer/Fc architectures; specific size and material properties (dependent claims).
Key Takeaways
- US 6,960,352 claims a local tumor/hyperplasia treatment method that works by VWF immobilized on a solid-phase carrier capturing and activating platelets to form a thrombus at a predetermined site to limit blood supply.
- The estate is platform-flexible (particles, coils, stents) and attachment-flexible (direct/indirect binding; spacer architectures; wide carrier material lists that retain VWF).
- The most infringement-sensitive design features are: (i) immobilized VWF as the platelet-binding agent, (ii) local predetermined delivery at/near tumor vasculature, and (iii) thrombus formation in vivo through VWF-mediated platelet capture/activation.
- Dependent claims add operational coverage for particle sizes, coils/stents coated with VWF, human/porcine/autologous/heterologous VWF sources, and targeting/attachment chemistries, which can increase leverage once an accused platform is technically characterized.
FAQs
- Does US 6,960,352 cover soluble VWF injected systemically without a solid carrier?
- Do VWF-coated coils or stents fall under the same patent coverage as VWF-coated particles?
- If a competitor uses VWF but a different platelet-binding mediator to trigger thrombosis, is infringement avoided?
- How do particle size limits in dependent claims affect enforceability if an accused product uses outside the stated micron ranges?
- Does claim 20’s macro-aggregated albumin embodiment expand risk beyond particle carriers to protein aggregate formulations?
References (APA)
No external sources were cited because the prompt did not provide bibliographic record details (filing date, assignee, family members, prosecution history, litigation, or FDA/Orange Book data) needed for compliant patent-landscape referencing.
