GlaxoSmithKline has presented positive data from a late-stage study of its new platelet-boosting treatment Revolade® (eltrombopag), one of the drugs in the firm’s pipeline that analysts believe can be a blockbuster.
Results from a pivotal international phase III study, presented at the European Haematology Association congress in Vienna recntely, showed that Revolade at 50–75mg once daily resulted in a statistically significant increase in platelet counts and also reduced bleeding in adult patients with chronic idiopathic thrombocytopenia purpura.
ITP is a low-platelet-count disorder that leaves sufferers at risk of spontaneous bruising, mucosal bleeding and, in severe cases, intracranial haemorrhage. It is estimated that 50,000–100,000 people have been diagnosed with chronic ITP in the USA alone and the predicted five-year mortality rates for ITP patients with persistent low platelet counts range from 2.2% for patients younger than 40 years, to 47.8% for those older than 60.
Patients on the trial were randomised to either placebo (38 patients) or eltrombopag 50mg (76 patients) once daily for six weeks, although the Revolade dose could be increased to 75mg in patients not responding after an initial three weeks of treatment. At the end of the trial, 59% of eltrombopag-treated patients and 16% of placebo-treated patients achieved a platelet count of more than 50,000/microlitre. Importantly, said GSK, there was a significantly lower incidence of bleeding events during treatment with Revolade compared to placebo.
Investigator Dr Drew Provan of the haematology department at the Royal London Hospital, UK, said options are particularly limited for those patients who fail to respond to primary treatment altogether and those who initially respond and then fail. Now, he added, “these trial results demonstrate that eltrombopag may represent the potential for a new oral therapy to reduce the number of bleeding episodes in ITP patients”.
Revolade, which will be marketed as Promacta® in the USA if approved, was discovered as a result of research collaboration between GSK and Ligand Pharmaceuticals, and several trials of the compound are ongoing.