Siponimod from Novartis is intended to treat a form of multiple sclerosis with no current treatment options. 

The central nervous system disease multiple sclerosis (MS) disrupts the flow of information within the brain, and between the brain and body, leading to a range of serious problems, including vision impairment and issues with arm and leg movement, sensation and balance. Diagnosis typically occurs between the ages of 20 and 50, and many more women than men suffer from the disease. Over 2.3 million people are thought to have MS; the actual number is known because diagnosis is difficult and reporting of diagnoses by physicians is not required.

The most common form of MS is relapsing-remitting MS (RRMS), in which clearly defined attacks of new or increasing neurologic symptoms occur between periods of remission, where all symptoms may disappear. Approximately 85 percent of people with MS are initially diagnosed with RRMS. RRMS can be further characterized as active or not active and worsening or not worsening. Secondary progressive multiple sclerosis (SPMS) follows RRMS. With SPMS, there is a progressive worsening of neurologic function over time. There are no current treatments available for SPMS.

That may change. Novartis recently reported positive Phase III trial results for siponimod, a drug it is developing for the treatment of SPMS. According to the company, patients taking siponimod had a 21% reduced risk of worsening disability after three months, and a 26% reduction after six months vs. placebo. Nearly one-third of the patients of placebo experienced increasing disability after three months. Novartis also reported that the drug showed positive effects on clinical relapses and MRI disease activity; brain volume loss decreased by 23%. 

Siponimod binds to the S1P1 sub-receptor on lymphocytes, causing a greater number of these cells to be retained in lymph glands and fewer to reach the brain. As a result, the likelihood of an immune attack on nerve cells in the brain and spinal cord is reduced. If approved, the drug would be the first oral disease-modifying therapy to delay disability progression. 

Novartis is expected to seek regulatory approval for siponimod from the US Food and Drug Administration in the next few weeks and to subsequently submit a filing with the European Medicines Agency.