GlaxoSmithKline has won approval in the USA for a new chemotherapeutic agent for T-cell acute lymphoblastic leukaemia (T-ALL) and T-cell lymphoblastic lymphoma (T-LBL), two rare cancers that together affect around 1,600 adults and children in the USA each year.

Arranon (nelarabine) has been approved for use in patients whose disease has not responded to or has relapsed following treatment with at least two chemotherapy regimens, said GSK in a statement. It is estimated that around 500 patients are in this non-responsive category.

Approval of the drug was granted on the basis of Phase II clinical trial results under the US Food and Drug Administration’s priority-review system for drugs that offer a therapy advance for conditions with few treatment options. No drug has been specifically approved to treat T-ALL and T-LBL, and current options have limited efficacy. An FDA advisory committee voted in favour of Arranon’s approval last month [[15/09/05b]].

Arranon is also in development in other haematological cancers that could dramatically increase the number of patients eligible for treatment with the drug and hike its sales potential up to around $500 million dollars a year, according to analysts.