Patent Issued for Technology to Suppress Stem Cell Rejection

(USPTO.gov)

Athersys Inc., a biotechnology company in Cleveland, Ohio, has received a patent for its process to reduce or suppress graft-versus-host disease associated with bone-marrow stem cell transplants used to treat leukemia and related disorders. Patent 8,147,824 was issued yesterday by the U.S. Patent and Trademark Office and assigned to Athersys, as well as the Oregon Health and Science University in Portland.

The company says the patent covers the technology behind its MultiStem platform to suppress graft-versus-host disease, when used with hematopoietic stem cell transplants that include transplants from bone marrow. The technology also covers non-embryonic, multipotent stem cells derived from other tissues sources, in addition to bone marrow, and applies to single or repeat doses over a range of dosage levels used in treatments involving hematopoietic stem cell transplants.

Graft-versus-host disease occurs in a bone marrow or stem cell transplant involving a donor and a recipient. The differences between the donor’s cells and recipient’s tissues often cause T cells – a type of white blood cells important to the immune system — from the donor to recognize the recipient’s body tissues as foreign. When this happens, the newly transplanted cells attack the transplant recipient’s body. Rates of the disease range from 30-40 percent for related donors to 60-80 percent for unrelated donors.

A transplant patient can take drugs to suppress the immune system, which can help reduce the chance or severity of graft-versus-host disease. Athersys says its MultiStem treatments offers an alternative that delivers a special class of human stem cells with the ability to express a range of relevant proteins and other factors, as well as form multiple cell types. The treatments, the company says, can reduce inflammation, protect damaged or injured tissue, and enhance the formation of new blood vessels.

In February, Athersys reported the results of a phase 1 clinical trial of MultiStem to test the safety of the treatments for undergoing hematopoietic stem cell transplants for the treatment of leukemia and related conditions. The study demonstrated that MultiStem therapy was well tolerated by patients who received both single and multiple infusions. While the trial’s main objective was to test the safety of MultiStem, the results also point to therapeutic benefit from the treatments with a relationship of lower occurrence or less severity of graft-versus-host disease among patients who received higher or more frequent doses.

In September 2010, Athersys received orphan drug designation for MultiStem from the Food and Drug Administration. Orphan drug designation applies to disorders affecting fewer than 200,000 individuals, and qualifies the product’s sponsoring company for tax credits and marketing incentives.

Read more: Stem Cells Shown to Help Treat Spinal Cord Injuries

*     *     *