Long-term Use of Gilenya Doesn’t Appear to Affect MS Patients’ Vision
Loss of macular volume over 4 years in small study likely due to disease
More than four years of treatment with Gilenya (fingolimod) did not cause significant swelling of the macula — a part of the retina, found in the back of the eye, and important for visual clarity — in people with relapsing-remitting multiple sclerosis (RRMS), a small study showed.
While significant decreases in macular volume were found over the study’s duration, indicating some nerve cell degeneration, these changes “may be attributable to the disease process itself rather than the direct effect of fingolimod,” the researchers wrote.
“Our findings confirm the relative safety, in the context of ocular side-effects, of fingolimod … in RRMS patients,” they added.
The study, “Effect of fingolimod therapy on quantitative macular changes among patients with relapsing-remitting multiple sclerosis: a four-year follow-up study from Oman,” was published in the journal BMC Ophthalmology.
Swelling in macula noted as potential side effect in Gilenya trials
Gilenya, marketed by Novartis, is a disease-modifying therapy indicated in the U.S. for patients ages 10 and older with relapsing forms of multiple sclerosis (MS). In Europe, its use is limited to those with highly active RRMS. Gilenya works by “trapping” immune cells inside lymph nodes, preventing them from getting into the nervous system and causing damage.
In Phase 3 clinical trials of the therapy, a buildup of fluid leading to swelling of the macula, a phenomenon called macular edema, was “a relatively infrequent side effect” of Gilenya’s use, the researchers noted. But such swelling affects the area responsible for central vision, the macula, and can cause blurry vision and color distortion. If untreated, it can lead to irreversible vision loss.
Most studies into macular changes covered up to one year of Gilenya treatment. A research team in Oman set out to evaluate Gilenya’s effects on the macula over four years in people with RRMS.
Data collected covered 21 RRMS patients on Gilenya and followed at a hospital in that country’s capital, Muscat, from January 2014 to December 2018. These people did not have risk factors for macular edema, such as diabetes, previous ocular surgeries, or a history of eye infections.
After an initial examination before treatment, patients had regular visits to an ophthalmologist at three, six, and 12 months after starting on Gilenya, at a daily 0.5 mg dose, and then annually for another three years.
At each visit, patients underwent basic ocular tests, including for visual acuity and color vision, and an optical coherence tomography assessment, a noninvasive technique to measure the thickness and volume of the macula. This test gives “useful quantitative measures to track changes in the central macula over the treatment period,” the researchers wrote.
Participants were mostly women (76.2%), with a mean age of around 40. Four patients had a prior history of optic neuritis, or inflammation in the nerves that send signals from the eyes to the brain.
Over the four-year study, no patient experienced macular edema or reported vision problems. There also were no significant changes in macula thickness.
However, while mean macular volume was stable at first, it decreased significantly towards the study’s end. A decline in macular volume of 0.15 mm3 was reported at one year, and of 0.138 mm3 at year three, with that reduction increasing to 0.507 mm3 at four years.
“This is likely due to the degenerative effect of the disease itself on the nerve fibres of the retina,” the researchers wrote.
Overall, the findings provide additional insights into the ocular health of RRMS patients on Gilenya, “indicating that the drug had no significant effect on the macula,” the researchers wrote.
However, “the impact of individual variations in our specific population cannot be discounted, such as disease severity, disability, age, the presence of other undiagnosed comorbidities [coexisting conditions] or a history of [eye inflammation],” they added. “Further research is recommended in order to determine the optimal safe duration of fingolimod treatment.”