The US Food and Drug Administration has given the green light to Teva Pharmaceutical Industries' Synribo to treat chronic myelogenous leukaemia.

The regulator has approved Synribo (omacetaxine mepesuccinate) is intended to be used in patients whose cancer progressed after treatment with at least two tyrosine kinase inhibitors, also used for CML. The injectable drug, which blocks certain proteins that promote the development of cancerous cells, has got the thumbs-up under the FDA’s accelerated approval programme, ie based on data showing that it has an effect that is reasonably likely to predict a clinical benefit.

The approval is based on an analysis of combined data subsets from two Phase II studies and the FDA notes that the drug’s effectiveness in chronic phase CML was demonstrated by a reduction in the percentage of cells expressing the Philadelphia chromosome genetic mutation found in most patients suffering from the blood and bone marrow disease. Fourteen out of 76 patients (18.4%) achieved a reduction in an average time of 3.5 months and the median length of the reduction was 12.5 months.

In accelerated phase CML, results showed that five out of 35 patients (14.3%) achieved major hematologic response in an average time of 2.3 months. The median duration of MaHR in these patients was 4.7 months.

Teva R&D chief Michael Hayden said the drug will help patients "who need additional treatment options when others have failed”. He added that Synribo joins the chemotherapy Treanda (bendamustine) and Trisenox (arsenic trioxide) for leukaemia "as important haematologic treatment options" in the firm's oncology portfolio.

Synribo is the second drug approved to treat CML in the past two months as in September, the FDA gave the green light to Pfizer's Bosulif (bosutinib). The American Cancer Society estimates that in 2012, there will be 5,430 new cases of CML diagnosed in the USA and 610 people will die from the disease.