Roche has ended development of its spinal muscular atrophy (SMA) drug olesoxime, citing "many difficulties".

The company acquired the drug from Trophos for €120 million ($140 million) in 2015.

"We have had many difficulties in developing this molecule for people with SMA," the company said in a statement to the SMA community shared online by TreatSMA. "These difficulties have focused on the formulation (the actual liquid preparation of olesoxime), the most appropriate dose to be given and requests from Health Authorities (FDA and EMA) to run a new Phase 3 study."

The company noted that while data at the 12 month point from the OLEOS study was promising, the most recent analysis at 18 months actually showed that olesoxime could lead to a worsening in motor function.

"Over the last few years, treatment options in SMA have also changed dramatically," Roche added. "The emergence of effective treatment has raised the hurdle for how effective a new treatment needs to be, and this has an impact on how we design and run our clinical studies."

Roche said that it remains "strongly committed to the SMA community", with the development of RG7916, an oral SMN2 splicing modifier, developed in collaboration with PTC Therapeutics and SMA Foundation.