There are estimated to be between 50,000 -- 100,000 individuals in the U.S. diagnosed with chronic Immune Thrombocytopenic Purpura (ITP), an autoimmune disease that dramatically reduces the number of platelets in their blood -- causing bruises, nosebleeds and, sometimes, life-threatening brain hemorrhages.
Now, the results of an international multicenter clinical research study led by NewYork-Presbyterian Hospital/Weill Cornell Medical Center demonstrate that an investigational oral platelet growth factor called eltrombopag successfully increased platelet counts and decreased bleeding in patients with the condition.
Published in today's 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.