The U.S. Food and Drug Administration (FDA) has approved Promacta®
(eltrombopag) for the treatment of patients with severe aplastic anemia who have had an insufficient response to immunosuppressive therapy (IST).
In a statement
, Dr. Paolo Paoletti, President of Oncology at GlaxoSmithKline (GSK) said, “FDA approval of Promacta addresses a significant treatment need for this very rare but serious blood disorder in those who have failed current treatment options,” adding, “Through collaboration with the National Institutes of Health, whose studies demonstrate the potential for Promacta to achieve a hematologic response in at least one lineage – red blood cells, platelets, or white blood cells – patients now have a treatment option where one didn’t previously exist.”
The approval of Promacta is based on results of a Phase II study (09-H-0154
) conducted by the National Heart, Lung and Blood Institute (NHLBI) at the National Institutes of Health (NIH). The study was a single-arm, open-label trial, in 43 patients with severe aplastic anemia (patients who had an insufficient response to at least one prior immunosuppressive therapy and who had a platelet count ≤30 x 109
/L). The primary outcome was a hematologic response to the drug and the study found:
40% (95% CI, 25, 56) of patients (N=17) experienced a hematologic response in at least one lineage – platelets, red blood cells (RBC), or white blood cells (ANC) – after Week 12
In the extension phase, 8 patients achieved a multi-lineage response; four of these patients subsequently tapered off treatment and maintained the response (median follow up 8.1 months, range 7.2-10.6 months).
In addition, the study found:
91% of patients were platelet transfusion-dependent at baseline; the platelet transfusion-free period in responders ranged from eight to 1,096 days (median 200 days)
86% of patients were RBC-transfusion dependent at baseline; the RBC transfusion-free period in responders ranged from 15 to 1,082 days (median 208 days)
The most common adverse reactions (≥20%) were: nausea (33%), fatigue (28%), cough (23%), diarrhea (21%), and headache (21%).
About Severe Aplastic Anaemia
Severe aplastic anemia is a very rare but serious blood disorder where the bone marrow fails to make enough blood cells. The exact cause of the disease is unknown, but most cases of severe aplastic anemia are believed to be triggered by an autoimmune reaction. In the United States, approximately 300 to 600 new cases of severe aplastic anemai are identified each year.
Severe aplastic anemia can often be treated with immunosuppressive drug regimens or allogeneic stem cell transplantation. However, 20-40%
of patients without transplant options do not respond to immunosuppressive therapies. Approximately 40% of patients who don’t respond to initial immunosuppressive therapy die from infection or bleeding within 5 years of their diagnosis. Those patients can now be treated with Promacta. At present, no other orphan drug is approved for aplastic anemia
Eltrombopag is marketed under the brand name Promacta in the U.S. and Revolad in most ex-U.S. countries.
Promacta is also approved for 1) chronic immune (idiopathic) thrombocytopenia who have had an insufficient response to corticosteroids, immunoglobulins, or splenectomy, and 2) chronic hepatitis C to allow the initiation and maintenance of interferon-based therapy.