DENVER – according to a retrospective study presented at the annual meeting of the Consortium of Multiple Sclerosis Centers. Those who switched did, however, experience a lower rate of inpatient infection-related health care visits per year than those who continued anti-CD20 mAbs.
“As MS is a chronic disease requiring long-term treatment, switching between disease-modifying therapies [DMTs] is a common clinical strategy to optimize individual patient outcomes,” lead author Aliza Ben-Zacharia, PhD, DNP, RN, an assistant professor at the Phillips School of Nursing at Mount Sinai and Hunter College, both in New York, and colleagues reported. They noted that anti-CD20 mAbs are considered high-efficacy DMTs while fumarates are considered moderate-efficacy DMTs.
The researchers used data from the Komodo Health Sentinel Claims Database to track and compare 108 patients who were clinically stable on anti-CD20 mAbs and then switched to fumarates with 540 patients who remained on anti-CD20 mAbs for a follow-up period of approximately 1 year.
The study included adults with a diagnosis of MS between January 2015 and August 2022, and only those with a gap of no more than 9 months between anti-CD20 mAbs and fumarates were included as switchers. The researchers also required that switchers had not had any relapses in the previous year on anti-CD20 mAbs before switching, and had to have been on fumarates for at least 3 months after switching.
Women made up 70% of both groups, and both had an average age of 49 years. The racial/ethnic demographics were similar in both groups, and the average MS severity score was 5.5 in the switching group and 5.6 in the staying group. Most patients had been taking or remained on ocrelizumab (93.5%) with a smaller proportion on rituximab (5.6%). Just over a third of those who switched therapy took diroximel fumarate while 64% took dimethyl fumarate.
The researchers noted that patients who stayed on anti-CD20 mAbs had “slightly higher use of other mAbs prior to anti-CD20 mAbs.” Further, “a higher proportion of patients were DMT naive prior to anti-CD20 mAb initiation, compared with those in the switchers group.”
Patients who switched had been on anti-CD20 mAbs an average 730 days before switching to fumarates, and the average time between their last anti-CD20 mAbs dose and starting fumarates was 274 days. Average exposure to fumarates was 341 days.
The 10.2% of patients who relapsed during follow-up after switching to fumarates was not significantly statistically different than the 6.7% of patients who relapsed while remaining on anti-CD20 mAbs (P = .17). A relapse was considered “an MS-related inpatient claim with a primary diagnosis of MS or an outpatient MS-related diagnosis and a prescription claim for an intravenous steroid, adrenocorticotropic hormone, total plasma exchange, or a high-dose oral corticosteroid 7 days or sooner after the outpatient visit,” the researchers explained. The researchers could not track mild relapses that didn’t involve a health care interaction.
There was also no significant difference in overall average health care encounters between those who switched (7.85 encounters) and those who stayed (8.08; P = .57). Further, average health care costs were statistically similar between those who switched ($22,512) and those who stayed ($20,634; P = 0.59).
The likelihood of having more than one infection-related health care encounter was greater for those who remained on anti-CD20 mAbs, but the difference was not statistically significant. The annual rate of infection-related health care encounters was also not statistically different for outpatient and ED visits, but those who switched did have a statistically lower rate of annual infection-related inpatient visits (P = .03).
Among those who switched, 2.8% were hospitalized for infections, compared with 6.5% who stayed on anti-CD20 mAbs. Urinary tract infections, sepsis, and Escherichia coli were the most common infections among those who switched to fumarates, compared with COVID-19, sepsis, and pneumonia, among those who stayed on anti-CD20 mAbs.
The research was sponsored by and funded by Biogen. Six of the authors are Biogen employees who hold stock options in the company. The other three authors reported combined consulting fees from Biogen, EMD Serono, Greenwich Biosciences, TG Therapeutics, Bristol-Myers Squibb, Horizon, and Novartis; research funding from Genentech and Novartis; and stock options in Pfizer.