In all, 65 patients were randomized to MD1003, and 28 patients to placebo. One patient did not enter the extension phase of the trial. Demographic characteristics were similar in the two treatment arms, but the majority of patients had nonprogressive chronic optic neuropathy, especially in the placebo arm. Slightly more patients randomized to MD1003 were taking disease-modifying therapies, compared with the placebo arm.
At six months, visual acuity improved in all patients. Improvement was more pronounced in patients receiving MD1003, but the difference between groups was not statistically significant. When the investigators examined only patients with nonprogressive chronic optic neuropathy, they found no difference between treatment groups at six months. When they examined participants with progressive chronic optic neuropathy, however, patients randomized to MD1003 had improved visual acuity at six months, while patients randomized to placebo had worsened visual acuity.
In the extension phase, patients who had improved on placebo continued to improve after switching to MD1003, and patients who had improved on MD1003 continued to improve. The researchers saw no differences in visual acuity between groups at 12 months. Among participants with nonprogressive chronic optic neuropathy, visual acuity improved in both treatment arms, and the researchers saw little difference between them at 12 months. Among patients with progressive chronic optic neuropathy, disease progression stopped in participants who switched from placebo to MD1003.
These results suggest that the treatment has no indication in patients with relapsing-remitting MS and show a trend toward efficacy in patients with progressive chronic optic neuropathy, which is consistent with the results of the MS-SPI study.
In addition, Dr. Tourbah and colleagues observed no major differences between treatment arms regarding the most frequent adverse events (ie, infections and infestations, nervous system disorders, and intestinal disorders). They noted, however, that more patients receiving MD1003 had relapses, compared with patients receiving placebo. “Whether MD1003 may trigger exacerbations in patients with relapsing-remitting MS deserves further investigation,” Dr. Tourbah concluded.
—Erik Greb