Experimental Medications: Other Therapeutic Strategies
Data from a Phase II dose-finding study of siponimod in people with RRMS were also reported in 2012. Siponimod has a relatively short half-life compared to Gilenya, which means that the drug does not stay in the body as long. Researchers hope that this will minimize cardiac issues.
The trial had a complex design in which the goal was to determine the most appropriate dosing regimen. One group of 188 patients received placebo or once-daily siponimod in doses of 10 mg, 2 mg, or 0.5 mg for six months. A second group of 109 patients were given one of two additional intermediate doses of 1.25 mg or 0.25 mg for three months.
At six months, the proportion of relapse-free patients as compared to placebo was 84 percent for the 10-mg group, 92 percent for the 2-mg group, and 77 percent for the 0.5-mg group. In the placebo group, 72 percent were relapse-free. After six months, the ARR (annual relapse rate) was lower for the individuals who were taking one of the three higher doses, as compared to those taking one of the two lower doses or the placebo. Additionally, MRI findings indicated that treatment with siponimod was associated with a reduction in active lesions on MRI. The 2-mg dose reached statistical significance versus placebo, with a reduction in active lesions of approximately 80 percent.
A Phase III trial of siponimod in secondary-progressive MS (the EXPAND trial)58 began recruitment in 2013, and is expected to run through Fall 2016. This is the first S1P receptor modulator to be studied in SPMS.