GlaxoSmithKline's Tafinlar (dabrafenib) is now on a fast track through the US regulatory system after winning 'breakthrough' status for a small subset of patients with lung cancer.

The US Food and Drug Administration has moved to accelerate the drug's development as an option for metastatic BRAF V600E mutation-positive non-small cell lung cancer (NSCLC), in patients who have received at least one prior line of platinum-containing chemotherapy. 

The move comes on the back of interim efficacy and safety data from an ongoing Phase II study of Tafinlar in patients with the mutation - which is thought to affect around 2% of those with NSCLC - presented last year at the annual meeting of the American Society of Clinical Oncology.

While no complete responses were observed (up to that point), 40% of patients had a partial response, 20% were considered to have stable disease and 30% had progressive disease, findings showed.

The drug has not been approved or licensed anywhere in the world for use in this setting, but just days ago the FDA issued a green light for Tafinlar  - in combination with Mekinist (trametinib) - to treat patients with unresectable or metastatic melanoma who have BRAF V600E or V600K mutations. 

Drisapersen rights returned to Prosensa

In other news, GSK has handed back to Dutch biotech Prosensa the rights to experimental Duchenne muscular dystrophy (DMD) therapy drisapersen and all other programmes for the treatment of the condition, marking the end of an agreement the firms signed in 2009.

According to the UK drug giant, the parties agreed that Prosensa is "well suited" to continue the development of drisapersen and five additional DMD programmes, three of which are in clinical development.

Drisapersen is in late-stage development for DMD and has been awarded orphan drug status in the EU, US, Japan and Australia, as well as Breakthrough Therapy designation across the pond.

However, hopes for the drug plummeted last year after data from a Phase III trial failed to show any statistical difference between drisapersen and a placebo in a crucial six-minute walk test in patients with the disease, causing Prosensa shares to crash more than 70%.