GENETICS INSTITUTE'S ERYTHROPOIETIN PURIFICATION TECHNIQUE

Executive Summary

GENETICS INSTITUTE'S ERYTHROPOIETIN PURIFICATION TECHNIQUE is one of three specific claims covered under a patent granted to the firm on June 30. The patent claims: "A method for purifying human erythropoietin comprising treating partially purified erthropoietin having a specific activity of at least about 80,000 IU per absorbance unit at 280 nanometers by reverse phase high performance liquid chromatography and eluting therefrom homogeneous human erythropoietin which moves as a single peak on reverse phase high performance liquid chromatography and is characterized by a specific activity of at least 160,000 IU per absorbance unit at 280 nanometers." "Patent claims on the actual substance cover a homogeneous erythropoietin characterized by a molecular weight of about 34,000 daltons on SDS PAGE, movement as a single peak on reverse phase high performance liquid chromatography and a specific activity of at least 160,000 IU per absorbance unit at 280 nanometers." In addition to the protein and purification process, the patent also covers the resulting pharmaceutical product. The product claim is for "a pharmaceutical composition for the treatment of anemia comprising a therapeutically effective amount of the homogenous erythropoietin [covered by the patent] in a pharmaceutically acceptable vehicle." The patent states that the purification technique used by Genetics Institute improves upon currently used purification procedures. The patent explains that current purification steps "include ethanol precipitation, DEAE-agarose fractionation, sulfopropyl-Sephadex chromatography, gel filtration and hydroxylapatite chromatography." The patent states that "the present invention . . . further [purifies erythropoietin] by reverse phase high performance liquid chromatography to obtain a homogeneous EPO [erythropoietin] protein." Purified EPO compositions produced by those techniques, the patent states, have "been found to be non-homogenous." The patent notes that "no matter what the source of EPO is [ie. natural or recombinant], the EPO protein must be purified to homogeneity for therapeutic use." In a July 1 release announcing the patent, Genetics Institute said it believes "that our patent claims cover all erythropoietin products currently undergoing clinical trials, both by licensees of Genetics Institute as well as unlicensed competitors." Genetics Institute licenses its EPO to the Japanes firm Chugai, which is currently conducting trials in Japan and plans to begin U.S. trials "shortly," the release states. Amgen, furthest along in the clinical development of EPO, is in Phase II trials with its recombinant product in kidney dialysis patients. Amgen has licensed EPO rights in Japan to Kirin and in the rest of the world, excluding China, to J&J. J&J also has rights to the non-dialysis anemia market for EPO in the U.S. Both Amgen and Genetics Institute have patents pending for a genetically engineered process for producing EPO.