GlaxoSmithKline plc [LSE/NYSE: GSK] announced today that the U.S. Food and Drug Administration (FDA) has approved PROMACTA for the treatment of thrombocytopenia (low blood platelet counts) in patients with chronic hepatitis C to allow them to initiate and maintain interferon-based therapy. PROMACTA is the first supportive care treatment available to patients who are ineligible or poor candidates for interferon-based therapy due to their low blood platelet counts. PROMACTA in combination with interferon-based therapy has been shown to improve a patient's chance of achieving a sustained virologic response (SVR) or viral cure.
There are limitations to the use of PROMACTA in patients suffering from chronic hepatitis C-associated thrombocytopenia. These include:
PROMACTA should not be used in an attempt to normalize platelet counts;
PROMACTA should be used only in patients with chronic hepatitis C whose degree of thrombocytopenia prevents the initiation of interferon therapy or limits the ability to maintain optimal interferon-based therapy; and
Safety and efficacy have not been established in combination with direct-acting antiviral agents approved for treatment of chronic hepatitis C genotype 1 infection.
"Chronic hepatitis C is a significant public health issue," said Paolo Paoletti, M.D., President, GlaxoSmithKline Oncology. "Some chronic hepatitis C patients suffer from low blood platelet counts. Commonly prescribed interferon-based therapies can worsen the problem of low blood platelet counts. Today's FDA approval of PROMACTA gives doctors a tool to address the low platelet challenge. This means more chronic hepatitis C patients may be able to start and stay on interferon-based therapy. That gives these patients a better chance to achieve a viral cure."
The approval for PROMACTA is based on results from ENABLE 1 and 2 (Eltrombopag to INitiate and Maintain Interferon Antiviral Treatment to Benefit Subjects with Hepatitis C related Liver DiseasE), two Phase III randomized, double-blind, placebo-controlled, multicenter studies, which collectively enrolled 1,521 patients with platelet counts <75,000/µL. ENABLE 1 utilized peginterferon alfa-2a (PEGASYS®) plus ribavirin for antiviral treatment and ENABLE 2 utilized peginterferon alfa-2b (PEGINTRON®) plus ribavirin.