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Eltrombopag Approved for Managing Low Platelets to Enable Hepatitis C Patients to Use Interferon

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The U.S. Food and Drug Administration has approved a new indication for eltrombopag (Promacta or Revolade), supporting its use for management of thrombocytopenia, or low platelet count, in people with chronic hepatitis C, GlaxoSmithKline announced last week.

Platelets are cell fragments that play a critical role in blood clotting. Eltrombopag, which stimulates proliferation of platelet precursor cells known as megakaryocytes in the bone marrow, was approved in 2008 for treatment of idiopathic thrombocytopenic purpura, or low platelets due to unknown cause.

Thrombocytopenia is a potential side effect of interferon-based therapy for hepatitis C, and interferon is generally considered contraindicated for people with pre-existing platelet deficiencies. Use of eltrombopag for this population is supported by a pair of Phase 3 clinical trials, which together enrolled more than 1500 participants, showing that eltrombopag enabled people to stay on adequate doses of pegylated interferon and ribavirin, thereby improving their chances of sustained virological response.

However, eltrombopag can cause liver toxicity and may potentially increasethe risk of hepatic decompensation, or liver failure, especially in people with advanced liver damage. GlaxoSmithKline cautioned that the drug should only be used to boost platelets in patients with thrombocytopeniaso severe that they could not otherwise use interferon-based therapy, not to normalize platelet counts in people with milder deficiency. Eltrombopag has not yet been adequately studied in combination with new HCV direct-acting antiviral agents.

Below is an edited excerpt from a GlaxoSmithSkine press release describing the new indication and its supporting data. The complete release, including important safety information, is available online.

FDA Approves New Indication for Promacta (eltrombopag)

First supportive care treatment approved for patients with thrombocytopenia with chronic hepatitis C to allow the initiation and maintenance of interferon-based therapy

November 19, 2012 -- 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, MD, 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/mcL. ENABLE 1 utilized peginterferon alfa-2a (Pegasys) plus ribavirin for antiviral treatment and ENABLE 2 utilized peginterferon alfa-2b (PegIntron) plus ribavirin.

11/27/12

Source

GlaxoSmithKline. FDA Approves New Indication for Promacta (eltrombopag). Press release. November 19, 2012.