The US Food and Drug Administration has given the green light to Talon Therapeutics’ orphan drug Marqibo to treat a rare type of leukaemia after the drug was fast tracked through the agency’s accelerated approval programme.

Specifically, Marqibo (vincristine sulphate liposome injection) will treat the rapidly progressing type of blood and bone marrow cancer, known as Philadelphia chromosome negative acute lymphoblastic leukaemia, indicated for patients that have relapsed two or more times or failed at least two other therapies.

The drug itself is a targeted version of the commonly used generic anti-cancer drug vincristine that has been specially packaged within a liposome. Liposomes act as drug-delivery vehicles and are composed of material similar to cell membranes.     

The news is particularly positive as the FDA had declined a marketing application for Marqibo in 2005, filed by two other companies, as a treatment for relapsed non-Hodgkin’s lymphoma. Talon licensed Marqibo in 2006 and will be the company’s first marketed product.

“This represents a transformational event for Talon and fulfilment of our most important corporate goal to date,” Talon chief executive Steven Deitcher said.

The company is now considering the rights to Marqibo outside the USA.

Marqibo is approved under the FDA’s accelerated approval programme, which allows the agency to approve a drug to treat a serious disease based on clinical data that shows the drug as an effect on a surrogate endpoint that is reasonably likely to predict a clinical benefit to patients. The programme aims to provide earlier patient access to new drugs while additional clinical trials take place to confirm the drug’s clinical benefit and safe use. Marqibo’s approval was based on three trials.

 “Marqibo’s approval demonstrates the FDA’s commitment to the development and approval of drugs that address serious, unmet medical needs,” said Richard Pazdur, director of the Office of Haematology and Oncology Products in the FDA’s Centre for Drug Evaluation and Research.

The prescribing information will carry a Boxed Warning regarding administration and dosing of the drug.