US regulators have expanded the scope of Novartis’ Promacta to include earlier use of the drug to treat adults and paediatric patients with severe aplastic anaemia (SAA) in combination with standard immunosuppressive therapy (IST).

The drug, an oral thrombopoietin receptor agonist, is already marketed in the US (and elsewhere as Revolade) to treat patients with the rare blood disorder who have had an insufficient response to IST.

It is also cleared to treat patients with chronic immune thrombocytopenia (ITP) who are refractory to other treatments, and for the treatment of thrombocytopenia in patients with chronic hepatitis C virus (HCV) infection.

Promacta’s (eltrombopag) approval in the first-line setting SAA setting is based on an analysis of research sponsored by the National Heart, Lung and Blood Institute Division of Intramural Research Program and conducted under a Cooperative Research and Development Agreement (CRADA).

The study showed that 44% of definitive IST-naive SAA patients achieved complete response at six months when treated with Promacta concurrently with standard IST, which was 27% higher than the complete response rate historically observed with the standard IST alone. The overall response rate was 79% at six months.

"Patients with SAA sometimes do not respond to the current treatment standard of IST," said Phillip Scheinberg, head, Division of Hematology, Hospital A Beneficência Portuguesa de São Paulo in Brazil, and previously with the Hematology Branch of the NHLBI.

"With this approval, physicians now have an option to add Promacta to the standard IST in a regimen that has demonstrated significant overall and complete response rates upfront in SAA and reduce the numbers of those who are unresponsive to initial therapy."

The drug is also under review in Europe for first-line treatment of SAA, with a decision expected sometime next year.