Patent Profile: Azaya Therapeutics' PSL Nanoparticle Patent Issues

    By Donald Zuhn ---

The United States Patent and Trademark Office recently issued U.S. Patent No. 7,179,484 to Azaya Therapeutics, Inc.  The '484 patent, which relates to protein-stabilized liposomal formulations for the delivery of pharmaceutical agents, is the first U.S. patent to be awarded to the San Antonio-based pharmaceutical company.

After receiving a Notice of Allowance in November 2006, Azaya announced that the '484 patent would allow the company to fully utilize its proprietary Protein Stabilized Liposome (PSL®) nanotechnology, which allows for the production of uniform liposomal particles of less than 200 nm in size in a single-step manufacturing process.  According to Azaya, the strength of its PSL® nanotechnology is that it can be used to encapsulate a large array of water insoluble drugs.

Azaya has described the '484 patent as a "core technology patent" that will allow the company to further develop its lead product candidate, ATI-1123.  ATI-1123 is a PSL® formulation of Aventis' Taxotere, which is a poorly water-soluble semi-sythetic taxane analog used in the treatment of non-small cell lung, prostrate, and breast cancer.  Prior to the development of Azaya's PSL® nanotechnology, Taxotere's poor water-solubility had been overcome by formulating the compound with a toxic carrier, Tween 80.

In addition, Azaya has been using its PSL® nanotechnology to develop a secondary product candidate, ATI-1153.  ATI-1153 is PSL® formulation of SN-38, which is an active metabolite of Pfizer's drug CAMPTOSAR® for use in treating colorectal cancer.  While SN-38 has proven to be more potent than alternative therapeutics, absent PSL® encapsulation, it cannot be administered directly to patients due to its water insolubility and high systemic toxicity.

The '484 patent issued from U.S. Application No. 10/703,187 and claims the benefit of U.S. Provisional Application No. 60/424,230, which was filed on November 6, 2002.  Representative independent Claim 1 recites:

1.  A method of preparing protein-stabilized liposome nanoparticles containing at least one lipophilic pharmaceutical agent, the method comprising:
    (a)  preparing an oil-in-water emulsion by a process comprising
        i)  preparing an organic solution comprising one or more phospholipids;
        ii)  mixing the at least one lipophilic pharmaceutical agent into said organic solution;
        iii)  infusing said organic mixture into an aqueous solution comprising an emulsion-forming protein, wherein said emulsion-forming protein comprises from about 0.1% to about 20% (w/v) of the aqueous solution, to form a the oil-in-water emulsion; and
    (b)  removing organic solvent from said emulsion to form the protein-stabilized liposome nanoparticles, wherein said liposome nanoparticles have sizes below 400 nm and said emulsion-forming protein adsorbed onto their surface.

Dependent claim 30 recites:

30.  A protein-stabilized lipid formulation comprising protein-stabilized liposome nanoparticles and a lipophilic pharmaceutical agent, the formulation prepared by a process selected from the group of processes consisting of those processes set forth in any one of claims 1, 2-9 and 10-29.

Additional information concerning Azaya's PSL® liposome nanoparticles and manufacturing process, including an animated simulation, can be found here.

Comments

[Bubba Gumpkin]

Why is this news?

[Donald Zuhn]

Bubba:

Thank you for expressing an interest in our blog. When we began "Patent Docs," one of our stated goals was to "highlight newly issued biotech and pharma patents" (see our first post on October 22, 2006). Our patent profiles constitute one way in which we are attempting to satisfy this goal.

By providing information on selected U.S. patents, it is our hope that "Patent Docs" will help patent professionals stay abreast of the biotech/pharma patent landscape. For example, the '484 patent discussed in the story above relates to liposomal drug delivery, an area of research that has seen quite a bit of recent patent activity. In addition, we believe that our patent profiles provide helpful information regarding the types of claims that the Patent Office is currently allowing. Finally, an analysis of our site stats indicates that most "Patent Docs" readers appear to be interested in the patent profiles.

Again, we thank you for reading our blog, and for taking the time to let us know what you think about "Patent Docs."

Don