FDA Grants Full Approval for PROMACTA® (eltrombopag) for Treatment of Rare Blood Disorder

PHILADELPHIA, Feb. 25, 2011 /PRNewswire/ -- GlaxoSmithKline (NYSE: GSK) today announced that the United States Food and Drug Administration (FDA) granted full approval for PROMACTA® (eltrombopag), an oral tablet that can raise platelet counts in patients with the rare blood disorder chronic immune (idiopathic) thrombocytopenic purpura (ITP) who have had an insufficient response to corticosteroids, immunoglobulins or splenectomy.

PROMACTA initially received FDA orphan drug designation in May 2008 and accelerated approval in November 2008 for chronic ITP.  The FDA Accelerated Approval program offers a pathway to gain provisional marketing approval for therapies that address unmet patient needs.  Full approval of the therapy requires completion of post-marketing clinical trials and commitments that verify clinical benefit.

"Full approval of PROMACTA was based on clinical studies that provide physicians and patients with a broader understanding of its treatment effect and safety profile," said Steven Stein, MD, V.P. of Medicines Development, GlaxoSmithKline.  "PROMACTA is a testament to how the FDA Accelerated Approval Program supports development of therapies that meet unmet patient needs. Patients with limited treatment options gained access to PROMACTA while GSK conducted clinical studies that yielded additional efficacy and safety data."  

About Chronic ITP

Chronic ITP is a disorder marked by increased platelet destruction and/or inadequate platelet production in the blood, which causes an increased risk of bruising and bleeding. There are estimated to be approximately 60,000 individuals diagnosed with chronic ITP in the U.S.  People with chronic ITP often bleed from small blood vessels causing bruises or nosebleeds.

Updated Prescribing Information (PI)

The major changes in the Prescribing Information of PROMACTA are to the Initial Dose Regimen and to the Thrombotic/Thromboembolic complications in the Warnings and Precautions section of the PI. The label also now includes efficacy and safety data from RAISE, a 6-month, randomized double-blind, placebo-controlled study in patients with ITP. The RAISE study which was published recently in the medical journal Lancet, showed that patients treated with PROMACTA were significantly more likely to achieve a platelet count between 50,000/microL and 400,000/microL during the entire 6-month treatment period compared to those patients treated with placebo.

The updated PI also incorporates two-year safety data from an open-label, single-arm extension study in patients with chronic ITP. This study showed that adverse reactions occurred in a pattern similar to those reported in the placebo-controlled studies.

Additional changes to the PI include updates on dose adjustments, risk of hepatotoxicity, bone marrow reticulin formation, thrombotic/thromboembolic complications, recurrence of thrombocytopenia, hematologic malignancies, cataracts, adverse event information, drug interactions, use in specific patient populations (hepatic and renal impairment) and to the pharmacokinetic section.   For more information, please review the full Prescribing Information (Available by request: Contact Rob Perry at [email protected]).  

BOXED WARNING and Important Safety Information

PROMACTA may cause hepatotoxicity.  Increases in serum aminotransferase levels and bilirubin were observed.  Liver chemistries must be measured before the initiation of treatment and regularly during treatment.  See Full Prescribing Information for BOXED WARNING.

Because of the risk of hepatotoxicity, and other risks including bone marrow reticulin and risk for bone marrow fibrosis, thrombotic/thromboembolic complications, recurrence of thrombocytopenia and hemorrhage risk after PROMACTA cessation, hematologic malignancies and progression of malignancies, and cataracts, PROMACTA is available only through a restricted distribution program called PROMACTA CARES.

Additional PROMACTA Information

PROMACTA is an oral, non-peptide thrombopoietin receptor agonist that has been shown in pre-clinical and clinical research to stimulate the proliferation and differentiation of megakaryocytes, the bone marrow cells that give rise to blood platelets.  PROMACTA was discovered as a result of a research collaboration between GlaxoSmithKline and Ligand Pharmaceuticals (Nasdaq: LGND). It was developed by GlaxoSmithKline.

Note to Editors

PROMACTA® is a registered trademark of the GlaxoSmithKline group of companies.

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Cautionary statement regarding forward-looking statements

Under the safe harbor provisions of the U.S. Private Securities Litigation Reform Act of 1995, GSK cautions investors that any forward-looking statements or projections made by GSK, including those made in this announcement, are subject to risks and uncertainties that may cause actual results to differ materially from those projected. Factors that may affect GSK' s operations are described under 'Risk Factors' in the 'Business Review' in the company' s Annual Report on Form 20-F for 2009.

SOURCE GlaxoSmithKline