Oral evobrutinib, an investigational highly selective Bruton’s tyrosine kinase inhibitor, may have a beneficial effect on reducing nerve damage in multiple sclerosis (MS), based on how it’s been found to lower levels of a key blood biomarker, according to a post hoc analysis of a placebo-controlled clinical trial reported at the American Academy of Neurology’s 2021 annual meeting.
Jens Kuhle, MD, of the department of biomedicine at University Hospital Basel, Switzerland, said the conclusion was based on reductions in blood levels of neurofilament light chain (NfL), a biomarker of neuroaxonal damage, in treated patients. “These data on the effect of evobrutinib on NfL dynamics are the first to be reported for a BTK inhibitor investigated for MS,” Kuhle said. Evobrutinib targets beta cells and myeloid cells, including macrophages and microglia, to disrupt NfL production.
The analysis consisted of three treatment arms in addition to the placebo arm: 25 and 75 mg daily, and 75 mg twice daily. The post hoc analysis included 166 patients across all arms, with 148 being evaluated at week 24.
Kuhle said the 75-mg twice-daily group exhibited significantly lower blood NfL levels as early as week 12 with lowered levels maintained to week 24, the last time point the study evaluated – specifically reductions of 18.9% (P = .01) and 16.8% (P = .040) compared with placebo, respectively.
However, the 75-mg once daily dose also showed meaningful reductions when compared with placebo: 15.4% (P = .043) and 14.1% (P = .10) at 12 and 24 weeks, respectively, Kuhle said. “There were no significant differences seen with the 25-mg once-daily group,” he said.
“These results are promising and indicate evobrutinib at an efficacious dose of 75 mg twice daily has a beneficial effect on reducing neuroaxonal damage in MS,” he said.
In an interview, Kuhle explained the importance of lower NfL levels. “The hope is that detecting subclinical disease activity in a sensitive and comprehensive way will lead to more effective treatment of the individual MS patient,” he said.
The findings may also inform future studies of evobrutinib in MS, he said. “Neurofilaments and neurons are the key substrate of permanent disability in MS and other neurodegenerative diseases,” Kuhle said. “It is anticipated that normalization of NfL to levels in same-age healthy controls should be the adequate treatment target for individual patients.”
NfL could be an “easily accessible and modifiable biomarker” for use in clinical trials of relapsing and progressive MS, he said. The researchers plan to use NfL measurements in the extension phase of the trial.
“An important next step is the development of reliable and age-adjusted reference values for NfL measurements in blood to move this biomarker further toward individual application in clinical practice,” he added, noting that his group has already collected more than 10,000 serum samples from more than 5,000 healthy controls to do that.
The analysis adds to the growing body of evidence supporting the use of blood NfL levels to gauge the effectiveness of disease-modifying therapies on neuroaxonal degeneration in MS, said Fredrik Piehl, MD, PhD, a professor at Karolinska University Hospital in Stockholm.
“However,” he added, “this is a short-term phase 2 trial lacking an active comparator. Inhibitors of BTK have been suggested to have a dual action, acting both in the periphery on the adaptive immune response, but also ameliorating local brain tissue inflammation.”
Additional studies with longer duration, active comparators and advanced neuroimaging will be needed to validate the effect of BTKs on NfL levels in MS, Piehl said.
The study was sponsored by EMD Serono Research and Development Institute, a Merck affiliate. Kuhle has no relevant financial relationships to disclose. Piehl reported financial relationships with Biogen, Novartis, Sanofi, Merck, Actelion, Alexion, Argenx, Roche/Genentech, Genzyme, UCB and Parexel.
This article originally appeared on MDedge.com, part of the Medscape Professional Network.