April 19, 2021 – Black patients with the autoimmune diseases multiple sclerosis (MS) or neuromyelitis optica spectrum disorder (NMOSD) may respond differently to a common MS treatment compared to their white peers, new research suggests.

White blood cells called B-cells are involved in the autoimmune response that damages the nervous system in people with MS and NMOSD. One common type of therapy, given as an infusion, targets a protein on B-cells called CD20 to kill the cells and stop them from playing their role in nerve degeneration.

In a new study of almost 200 patients, researchers found that B-cells came back sooner in Black participants with MS or NMOSD 6 to 12 months after they received anti-CD20 infusion therapy with rituximab or ocrelizumab, compared to white participants.

"The results showed that this B-cell targeted therapy wore off more quickly in African-Americans," said study co-investigator Gregg J. Silverman, MD, of the NYU Grossman School of Medicine in New York City.

Overall, "our findings raise the question of whether the same therapy dose may be equally effective for all people," co-investigator Ilya Kister, MD, also from NYU Langone Health, said in a press release. Kister noted that this could have implications for the way Black patients with autoimmune diseases are treated in the future.

The new study, presented at the virtual American Academy of Neurology 2021 Annual Meeting, included 168 participants who had a diagnosis of MS or NMOSD or who were considered to have MS or NMOSD. Thirty-six percent of the participants self-identified as Black or African American, 36% self-identified as White, and 28% self-identified as another race.

Researchers tested participants’ blood to look for B-cells coming back at various time points after they had received anti-CD20 infusions.

Results showed that no patients had B-cells coming back before 4 months after treatment, but 30% of all participants had B-cells coming back at about 7 months after infusion, on average.

From 4 to 6 months after infusion, B-cells came back in about 20% of both Black and white participants.

However, about 75% of Black participants had their B-cells come back between 6-12 months after infusion, compared to about 30% of white participants.

Overall, the findings "may have implications for clinical management of MS/NMOSD" in Black patients, the investigators wrote.

"At a minimum, this has raised our vigilance," said Silverman. "It gives us an answer, but it raises even more questions, which may well be important for helping us understand how the agent works and how the disease affects different people."

Patients typically get anti-CD20 therapy infusions targeting their B-cells every 6 months, said Eric Klawiter, MD, director of the multiple sclerosis and NMO unit at Massachusetts General Hospital in Boston.

Klawiter noted that his current practice is to check whether B-cells are coming back at the time of a patient's next infusion. If he sees they are, "I am already then making adjustments with their next infusion as to the dosing frequency," he said.

"If we can identify certain characteristics that would lead you to want to evaluate for the need of re-dosing sooner, I think that would be useful," Klawiter said.