Prior art — US Patent 7704721

The USPTO Patent Public Search tool is the definitive resource for searching US patents. I will identify the most relevant prior art cited within US patent 7704721. The patent lists "Patent Citations" and "Non-Patent Citations". For this task, I will focus on the patent citations. According to the MPEP, a reference is generally presumed to be operable and enabling for anticipation purposes if it expressly anticipates all elements of the claimed invention.

Here are the patent citations listed in US7704721 and their analysis:

1. US6194191B1

Full Citation: US6194191B1 - Method for the production and purification of adenoviral vectors
Publication/Filing Date: Publication: 2001-02-27. Filing: 1996-11-20 (priority date).
Brief Description: This patent describes a method for the production and purification of adenoviral vectors. It focuses on methods to obtain high yields of purified adenoviral vectors, often involving purification steps like chromatography.
Potential Anticipation (35 U.S.C. § 102):
- Claim 1: This patent potentially anticipates aspects of Claim 1, particularly step 2) "purifying rAAV virions from the lysate using ultracentrifugation and/or chromatography". While US6194191B1 specifically deals with adenoviral vectors, the general principles of purification using chromatography are similar. However, it does not directly teach the prevention of AAV aggregation with multivalent ions at a specific ionic strength, or the use of rAAV. Therefore, it may anticipate the purification methodology (chromatography) for viral vectors, but not the specific composition or ionic strength conditions for AAV aggregation prevention as claimed in 7704721.

2. US6566118B1

Full Citation: US6566118B1 - Methods for generating high titer helper-free preparations of released recombinant AAV vectors
Publication/Filing Date: Publication: 2003-05-20. Filing: 1997-09-05 (priority date).
Brief Description: This patent details methods for producing high-titer, helper-free recombinant adeno-associated virus (rAAV) vectors. It focuses on processes for generating the vectors and releasing them from host cells.
Potential Anticipation (35 U.S.C. § 102):
- Claim 1: US6566118B1 directly relates to "recombinant adeno-associated virus (rAAV) virions" and their preparation, which aligns with step 1) "providing a lysate comprising rAAV virions" and the overall subject matter of Claim 1. However, it does not specifically describe adding multivalent salts to achieve a high ionic strength (at least 200mM) to prevent aggregation at high concentrations (exceeding 1x10^13 vg/ml up to 6.4x10^13 vg/ml) while maintaining a pH between 7.5 and 8.0, which are key differentiating features of Claim 1 of US7704721.

3. WO1999061643A1

Full Citation: WO1999061643A1 - Method of preparing recombinant adeno-associated virus compositions by using an iodixananol gradient
Publication/Filing Date: Publication: 1999-12-02. Filing: 1998-05-27 (priority date).
Brief Description: This international patent application describes methods for preparing recombinant adeno-associated virus (rAAV) compositions, specifically utilizing an iodixanol gradient for purification.
Potential Anticipation (35 U.S.C. § 102):
- Claim 1: Similar to US6566118B1, this reference focuses on the purification of rAAV virions (step 2) of Claim 1). The use of an "iodixanol gradient" falls under the broad category of "ultracentrifugation and/or chromatography". However, it does not disclose the specific formulation conditions (multivalent salts, ionic strength, concentration range, pH) for preventing aggregation as defined in step 3) of Claim 1.

4. US6146874A

Full Citation: US6146874A - Method of preparing recombinant adeno-associated virus compositions
Publication/Filing Date: Publication: 2000-11-14. Filing: 1998-05-27 (priority date).
Brief Description: This patent describes a method for preparing recombinant adeno-associated virus compositions. It covers various aspects of AAV production and purification.
Potential Anticipation (35 U.S.C. § 102):
- Claim 1: This patent is broadly related to the preparation of rAAV compositions, which encompasses the provision and purification of rAAV virions (steps 1 and 2 of Claim 1). However, like the other cited AAV-related patents, it does not explicitly disclose the specific combination of multivalent salts, high ionic strength (at least 200 mM), high concentration (exceeding 1x10^13 vg/ml up to 6.4x10^13 vg/ml), and pH (7.5-8.0) for preventing aggregation, which are central to Claim 1 of US7704721.

5. US6593123B1

Full Citation: US6593123B1 - Large-scale recombinant adeno-associated virus (rAAV) production and purification
Publication/Filing Date: Publication: 2003-07-15. Filing: 2000-08-07 (priority date).
Brief Description: This patent describes methods for large-scale production and purification of recombinant adeno-associated virus (rAAV). It mentions using cation exchange chromatography for purification, a method also described in US7704721.
Potential Anticipation (35 U.S.C. § 102):
- Claim 1: This patent is highly relevant as it focuses on "large-scale recombinant adeno-associated virus (rAAV) production and purification," directly addressing step 1) and 2) of Claim 1. The purification methods, including cation exchange chromatography (as mentioned in US7704721's Example 1, Method 2, which refers to US6593123), are relevant. While it addresses the challenge of large-scale production and purification, which implicitly deals with maintaining stability, it does not explicitly teach the specific aggregation-preventing composition (multivalent salts, ionic strength of at least 200 mM, specific concentration range, and pH 7.5-8.0) that forms the core of step 3) of Claim 1 in US7704721.

In summary, the cited prior art patents generally describe methods for producing and purifying viral vectors, specifically rAAV. They address aspects like providing lysate and purification techniques (ultracentrifugation and chromatography). However, none of them appear to fully anticipate the specific combination of features in Claim 1 of US7704721, particularly the addition of specific multivalent salts to achieve an ionic strength of at least 200 mM to a purified, highly concentrated rAAV preparation (exceeding 1x10^13 vg/ml up to 6.4x10^13 vg/ml) at a pH between 7.5 and 8.0 for the purpose of preventing aggregation. The novelty of US7704721 appears to lie in this specific formulation for aggregation prevention in highly concentrated AAV preparations.