Press Release

New 48-week frexalimab phase 2 data support potential for high sustained efficacy in multiple sclerosis - Seite 2

Erik Wallström, MD, PhD
Global Head of Neurology Development, Sanofi
“Frexalimab represents a novel potential first-in-class treatment mechanism in multiple sclerosis designed to tackle the aspects of this disease where unmet medical needs still exist. We are applying our deep expertise to address the full spectrum of neuroinflammation and neurodegeneration to improve the lives of people living with multiple sclerosis.”

Results of the phase 2 OLE at week 48 showed:

• 96% of patients who continued receiving high-dose frexalimab and 87% of those who continued receiving low-dose frexalimab were free of Gd+ T1 lesions at week 48, respectively. Additionally, among patients who switched from placebo to high and low-dose frexalimab at the start of the OLE at week 12, declines were seen at Week 24, and 90% and 92% were free of Gd+ T1 lesions at week 48, respectively.
• The number of Gd+ T1-lesions (mean [SD]) remained low in participants who continued receiving frexalimab (high dose: 0.0 [0.2]; low dose: 0.2 [0.5]) and continued to decline in those who switched from placebo to frexalimab at week 12 (high dose: 0.2 [0.6]; low dose: 0.1 [0.3]).
• Number of and volume change of new or enlarging Gd+ T2-lesions remained low for all frexalimab treatment groups through week 48, and lymphocyte counts remained stable.
• Participants who continued receiving high-dose frexalimab experienced a low annualized relapse rate (ARR) of 0.04 (95% CI: 0.01, 0.18) over the 48-week treatment period with 96% being free of relapses. ARR in the initial low-dose arm was 0.22, and ARR in patients who switched to high and low-dose frexalimab were 0.09 and 0.40, respectively, through week 48.

Frexalimab was generally well-tolerated through week 48. The most common adverse events (≥10%) amongst all subgroups of patients receiving frexalimab during OLE until cut-off at week 48 from baseline were nasopharyngitis (n=14 [11%]), headache (n=14 [11%]) and COVID-19 (n=13 [10%]).

About the phase 2 study
The phase 2 study was a randomized, double-blind, placebo-controlled study evaluating frexalimab in participants with relapsing MS. Participants were randomized (4:4:1:1) to receive either high (frexalimab 1200 mg intravenously every four weeks, with an initial 1800 mg loading dose) or low (frexalimab 300 mg subcutaneously every two weeks, with an initial 600 mg loading dose) doses of frexalimab or matching placebo for 12 weeks (Part A). The primary endpoint was the reduction in the number of new Gd+ T1 MRI brain lesions at week 12. Secondary endpoints included additional MRI-based efficacy measures as well as the safety, tolerability and pharmacokinetics of frexalimab. After week 12, participants receiving placebo switched to respective frexalimab arms and entered the open-label Part B, which is currently ongoing.