Oct. 18 /PRNewswire/ -- Valentis Inc (Nasdaq: VLTS - news) today announced that the U.S. Patent and Trademark Office has granted PolyMASC Pharmaceuticals plc, Valentis' wholly owned subsidiary, a broad patent covering polyethylene glycol (PEG) modified liposomes. The patent, U.S. Patent Number 6,132,763, is titled ``Liposomes'' and is based on pioneering work by PolyMASC inventors in PEG technology (the field of attaching PEG chains to biomolecules).
``The issuance of this patent is an important event,'' said Benjamin F. McGraw III, President and CEO of Valentis. ``When we acquired PolyMASC in August, 1999, we believed the LipoMASC(TM) patent portfolio contained significant value. We initially intended to sell the entire liposomal intellectual property portfolio to a single purchaser. However, based on the issuance of this patent and in consideration of the associated patents and applications, we have since concluded that we can maximize the value of this intellectual property by licensing rights to a number of pharmaceutical companies who have present or future uses for the particular benefits of PEGylated liposome drug delivery.''
Dr. Gillian Francis, Managing Director of PolyMASC stated, ``In addition to PEG liposomes made via a range of different manufacturing routes, this patent also covers our LipoMASC(TM) technology. LipoMASC(TM) uses a specialized manufacturing process for PEG modifying the exterior of intact liposomes. The process is important because it conserves the interior carrying capacity of the liposome whereas recent studies (Nicholas et al. BBA 1463:167; 2000) show that traditional PEG techniques use up a large proportion of interior space, reducing liposomes' effectiveness. We are particularly excited by developments surrounding our LipoMASC(TM) technology which show advantages for tumor localization over other PEG-liposomes.''
``PEG-liposome products have already proven successful in the market and a number of other products are currently in clinical development,'' added Dr. Francis. ``This new patent covers a broad range of PEG-liposome formulations, from small unilamellar vesicles, to large unilamellar or multilamellar vesicles and is one of a broad portfolio of issued and pending patents that include US, European and Japanese claims over both the PEG liposomes themselves as well as over specialized lipid formulations that enhance tumor localization.''
Liposomes are used to improve the efficacy of small molecule drugs by encapsulating them in lipids. PEGylation of liposomes modifies the circulation of the liposomes in the body, enhancing tumor localization and reducing non-specific uptake in normal tissues. PolyMASC's proprietary technology, LipoMASC(TM), uses a specialized form of PEG liposome that maximizes the dose of liposomes delivered to the tumors while reducing the levels circulating in the blood.
Tumor localization is complex and relates, in part, to the fact that tumor blood vessels are leaky and allow the liposomes to enter the tumor tissue from the blood stream. Normal blood vessels are not leaky, and thus the ratio of drug delivered to tumours versus that delivered to normal tissues is improved. Because blood vessels at sites of inflammation are also leaky, the LipoMASC(TM) technology may lead to safer and more effective anti-cancer and anti-inflammatory agents... |
