Platelet Growth Factor Decreased Bleeding In Patients With The Autoimmune Bleeding Disorder

Published in the New England Journal of Medicine and representing the largest ever clinical trial of its kind for ITP patients, the Phase 2 study found that eltrombopag doses of 50 and 75 mg daily elevated platelet counts to a safe level (= 50,000 per cubic millimeter) in more than 75 percent of chronic ITP patients within two weeks -- compared to 11 percent of patients receiving placebo. As long as the therapy was administered, platelet counts continued to rise or remain increased, and bleeding symptoms decreased. Incidence and severity of adverse effects was similar in the placebo and eltrombopag treated groups.

"These findings represent an important step in the development of a new treatment option for those living with chronic ITP. The fact that eltrombopag elevated platelet counts in this study within one week could be very useful to chronic ITP patients in need of short-term treatment," says the study's principal investigator, Dr. James Bussel, director of the platelet research and treatment program at the Phyllis and David Komansky Center for Children's Health at NewYork-Presbyterian Hospital/Weill Cornell Medical Center and professor of pediatrics in obstetrics and gynecology and in medicine at Weill Cornell Medical College.

The study represents the second major clinical study of a platelet growth factor for ITP. In October 2006, Dr. Bussel was the lead author of publication reporting the results of a Phase I, II study of AMG 531, also in the New England Journal of Medicine.

Current and future studies will evaluate the safety and efficacy of eltrombopag as a long-term treatment for ITP, and its efficacy and safety in populations like the four million Americans with hepatitis C or patients receiving myelosuppressive chemotherapy.

Co-authors included Weill Cornell's Dr. Bethan Psaila, and physician-scientists from Prince of Wales Hospital in Hong Kong; George Cancer Specialists in Tucker, Ga.; Hematology Research Center in Moscow, Russian Federation; Hôpital La Rabta in Tuhis, Tunisia; Akademia Medyczna in Bialystok, Poland; GlaxoSmithKline in Collegeville, Pa. and Greenford, U.K.; and Barts & The London School of Medicine, London.

The study was financially supported by GlaxoSmithKline. Dr. Bussel is an Advisory Board Member for GlaxoSmithKline and has received research grant support, lecture fees, and consulting fees from GlaxoSmithKline and reports equity ownership in GlaxoSmithKline.

Immune thrombocytopenic purpura

Immune thrombocytopenic purpura (ITP) is an autoimmune disease in which anti-platelet antibodies accelerate destruction of platelets. ITP patients commonly have platelet counts of less than 30,000 per cubic millimeter, compared to normal platelet counts of between 150,000 and 440,000. ITP affects women of child bearing age at 2-to-3 times the rate of men.