DENVER – , new research shows.
“In long-term observations, we are seeing a nice, sustained suppression of relapses early, as well as late, in treatment,” said study investigator Anthony Traboulsee, MD, University of British Columbia, Vancouver, in presenting the findings at the annual meeting of the Consortium of Multiple Sclerosis Centers.
“It remains very tolerable with no participants discontinuing because of side effects,” he said. “And importantly, [there are] no signs of a delayed risk of infections for both monotherapy and combination therapy.”
Satralizumab, a monoclonal recycling antibody, targets the interleukin (IL)–6 receptor, which is elevated in the serum and cerebrospinal fluid of patients in NMOSD.
The drug was approved by the Food and Drug Administration in 2020 for the treatment of AQP4 antibody–positive NMOSD after favorable results from two key trials: SAkuraSky and SAkuraStar.
The FDA approval marked satralizumab as the third therapy for NMOSD, following eculizumab (Soliris) and inebilizumab (Uplizna).
Satralizumab is administered in subcutaneous injections every 4 weeks after a run-in period of injections at weeks 0, 2, and 4.
Longest trial to date
To evaluate the drug’s long-term efficacy in the treatment of AQP4 IgG–positive NMOSD, patients from the two previous phase 3 trials were entered into the single arm, open-label SAkuraMoon study and continued treatment with the satralizumab 120 mg injections once monthly, with or without immunosuppressive therapy.
The study included 106 patients (mean age 44 years, 89.6% women), all of whom had received one or more doses of satralizumab by the data cutoff of January 2022.
With a median duration of satralizumab exposure of 5 years, the overall adjusted annualized rate of investigator protocol-defined relapse (ARR) was 0.09.
Longitudinal assessment further showed no significant increase in the relapse rate over the course of the study, with an ARR rate of 0.16 at year 1; 0.10 at year 2; 0.05 at year 3; and 0.07 at year 4.
At week 240 (4.6 years), 72% of satralizumab-treated patients were relapse-free, with 91% free from severe relapse.
In addition, 85% of patients had no sustained disability, as measured by Expanded Disability Status Scale (EDSS) worsening, over the study period.
Asked if there are potential subgroups of patients who may be more susceptible to the worsening of disability, Dr. Traboulsee responded “not that we can tell as of yet.”
“I would like to explore this further as this is a relatively new observation, and, as far as I know, this is the longest follow-up for an NMO treatment trial cohort,” he said.
Favorable safety profile
The safety profile was also favorable, consistent with results in the earlier trials. The longer exposure to satralizumab was not associated with a higher risk of severe (grade 3 or higher) laboratory changes versus the double-blind studies. “Rates of adverse events and serious adverse events with overall satralizumab treatment were comparable with the double-blind periods,” said Dr. Traboulsee.