Siponimod May Benefit Patients With Secondary Progressive MS

Among patients with secondary progressive multiple sclerosis (MS), siponimod appears to decrease the risk of disability progression, according to data published online ahead of print March 22 in Lancet. The drug’s safety profile is similar to those of other sphingosine-1-phosphate receptor modulators, and siponimod “might be a useful treatment for patients with secondary progressive MS,” according to the authors.

To date, no molecule has slowed disability progression consistently in clinical trials of patients with secondary progressive MS. Preclinical data indicate that siponimod might prevent synaptic neurodegeneration and promote remyelination. The drug reduced the number of active brain lesions and the annualized relapse rate in a phase II study.

Patients Received 2 mg/day of Oral Siponimod

Ludwig Kappos, MD, Professor of Neurology at the University of Basel in Switzerland, and colleagues conducted a double-blind, phase III trial to assess siponimod’s efficacy and safety in patients with secondary progressive MS. They enrolled 1,651 patients at 292 hospitals and MS centers in 31 countries. Eligible participants were between ages 18 and 60, had an Expanded Disability Status Scale (EDSS) score of 3.0 to 6.5, a history of relapsing-remitting MS, EDSS progression in the previous two years, and no evidence of relapse in the three months before randomization.

Ludwig Kappos, MD

The investigators randomized patients 2:1 to once-daily oral siponimod (2 mg) or matching placebo. A trained assessor performed a full neurologic examination every three months. Participants underwent MRI scans at baseline, 12 months, 24 months, 36 months, and the end of the controlled treatment phase. Patients with six-month confirmed disability progression during the double-blind phase were given the opportunity to continue double-blind treatment, switch to open-label siponimod, or stop study treatment and remain untreated or receive another therapy.

The study’s primary end point was time to three-month confirmed disability progression, which was defined as a one-point increase in EDSS for patients with a baseline score of 3.0 to 5.0, or a 0.5-point increase for patients with a baseline score of 5.5 to 6.5. The key secondary end points were time to three-month confirmed worsening of at least 20% from baseline on the Timed 25-Foot Walk (T25FW) and change from baseline in T2 lesion volume.

Treatment Did Not Affect the T25FW

Dr. Kappos and colleagues randomized 1,105 patients to siponimod and 546 patients to placebo. Baseline characteristics were similar between the two study arms. Mean age was 48, and about 60% of patients were women. Participants’ median time in the study was 21 months, and median exposure to study drug was 18 months. Approximately 82% of the siponimod group and 78% of controls completed the study.

The rate of three-month confirmed disability progression was 26% in the siponimod group and 32% in the placebo group. Siponimod thus reduced the risk of this outcome by 21%. The researchers did not observe a significant difference between groups in time to three-month confirmed worsening of at least 20% on the T25FW. The mean increase in T2 lesion volume from baseline was 183.9 mm3 in the siponimod group and 879.2 mm3 among controls.

Siponimod reduced the risk of six-month confirmed disability progression by 26%, compared with placebo. It also was associated with a lower annualized relapse rate and a longer time to confirmed first relapse, compared with placebo.

The rate of adverse events was 89% in the siponimod group and 82% among controls. The rate of serious adverse events was 18% in the siponimod group and 15% among controls. The most frequent adverse events were headache, nasopharyngitis, urinary tract infection, and falls. Serious adverse events included increased liver transaminase concentrations, basal cell carcinoma, concussion, depression, urinary tract infection, suicide attempt, gait disturbance, MS relapse, and paraparesis. The rate of discontinuation because of adverse events was 8% for siponimod and 5% for placebo.

Subgroup analyses suggested that the treatment effect of siponimod decreased with increasing age, disability, baseline disease duration, and diminishing signs of disease activity. One interpretation of this finding “is that siponimod exerts its effect on both aspects of the pathogenesis of secondary progressive disease, albeit not equally,” according to the authors.

The study was funded by Novartis Pharma, which helped design and conduct the study; collect, manage, analyze, and interpret the data; and write the study report.

Drug Might Affect Inflammatory Activity

“The reduction in the proportion of participants reaching the primary end point of only 6% and the absence of a significant difference for the key secondary clinical outcome are disappointing results and do not suggest that siponimod is an effective treatment for secondary progressive MS,” said Luanne M. Metz, MD, Professor of Medicine, and Wei-Qiao Liu, MD, a doctoral student, both at the University of Calgary, Alberta, in an accompanying editorial.