Novartis is seeking approval on both sides of the Atlantic for use of experimental multiple sclerosis therapy siponimod to treat secondary progressive forms of the disease.

Secondary progressive multiple sclerosis (SPMS) is characterised by continuous worsening of neurological function over time, independent of relapses.

Most people with relapsing remitting forms of MS will eventually go on to develop SPMS; on average, around 65 percent will develop SPMS 15 years after being diagnosed, according to the MS Society.

Siponimod is a selective modulator of specific types of the sphingosine-1-phosphate (S1P) receptor, commonly found on the surface of specific cells in the central nervous system responsible for causing damage that drives loss of function in SPMS.

The drug enters the brain binding to these specific receptors, which may prevent the activation of these harmful cells, potentially helping to reduce loss of physical and cognitive function associated with the condition.

The US and EU filings contain data from the Phase III EXPAND study, which show significant reductions in the risk of three- and six-month confirmed disability progression with siponimod versus placebo and favorable outcomes in other relevant measures of MS disease activity.

The drug cut the risk of three-month confirmed disability progression by 21 percent, the risk of six-month confirmed disability progression by 26 percent, and the annualised relapse rate by 55 percent versus placebo.

Data from the Phase II BOLD study also showed that siponimod significantly reduced the annualised rate of relapses (ARR) over six months compared to placebo (0.20 vs. 0.58, respectively) in patients with SPMS.

"Siponimod is the first investigational medicine to show a significant delay in disability progression in typical SPMS patients," said Paul Hudson, chief executive of Novartis Pharmaceuticals. "We are closely working with the FDA and EMA to ensure siponimod is available for patients as soon as possible."

Regulatory action for siponimod is anticipated in the US in March of 2019 and in Europe in late 2019, the Swiss drug giant said.