Ligand Pharmaceuticals Incorporated (NASDAQ: LGND) partner GlaxoSmithKline (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.
“This is a tremendous achievement for this field of medicine. Otherwise very sick patients, who had little to no therapeutic options, will now have an opportunity to potentially receive treatment for hepatitis C. We commend GSK's PROMACTA team, and particularly Drs. Arning, Amado and Paoletti, for their leadership and commitment to driving PROMACTA to this regulatory success,” commented John Higgins, President and Chief Executive Officer of Ligand Pharmaceuticals. “We are extremely pleased with the decision by the FDA, and look forward to the near-term launch of PROMACTA for this important new indication.”
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.Important Safety Information for PROMACTA BOXED WARNING PROMACTA may cause hepatotoxicity. PROMACTA, in combination with interferon and ribavirin in patients with chronic hepatitis C, may increase the risk of hepatic decompensation. Patients receiving therapy with PROMACTA must have regular monitoring of serum liver tests (see Laboratory Monitoring). Discontinue PROMACTA if ALT levels increase to ≥3X upper limit of normal (ULN) in patients with normal liver function or ≥3X baseline in patients with pre-treatment elevations in transaminases and are: progressive; or persistent for ≥4 weeks; or accompanied by increased direct bilirubin; or accompanied by clinical symptoms of liver injury or evidence of hepatic decompensation. Reinitiating treatment with PROMACTA is not recommended and should be considered only with close medical supervision and under exceptional circumstances where the potential benefit outweighs the risk. Additional Safety Information Regarding Risk of Hepatotoxicity: Reinitiating treatment with PROMACTA is not recommended. If the potential benefit for reinitiating treatment with PROMACTA is considered to outweigh the risk for hepatotoxicity, then cautiously reintroduce PROMACTA and measure serum liver tests weekly during the dose adjustment phase. If liver test abnormalities persist, worsen or recur, then permanently discontinue PROMACTA.