Novartis Announces Positive Biomarker Results for Del-brax in FSHD

The FSHD community received encouraging news today as Novartis announced that delpacibart braxlosiran (del-brax) met the primary and key secondary endpoints in the biomarker cohort of the Phase 1/2 FORTITUDE clinical trial. 

Del-brax is an investigational therapy designed to target the root cause of FSHD by reducing the activity of DUX4. In this study, participants receiving del-brax showed reductions in KHDC1L, a biomarker linked to DUX4 activity, as well as reductions in creatine kinase (CK), a marker of muscle damage. The safety profile was consistent with previous studies. 

While clinical benefit remains to be studied, these results provide additional evidence that the therapy is reaching its intended target and may be helping reduce muscle injury. Biomarker findings like these are an important part of the development of disease-modifying treatments for FSHD. 

Some community members may know del-brax from earlier announcements by Avidity Biosciences, the company that originally developed the therapy. In February 2026, Novartis completed its acquisition of Avidity, bringing del-brax and several other neuromuscular programs into its pipeline. Development of the therapy continues under Novartis, including the ongoing Phase 3 FORTITUDE-3 trial, which is currently enrolling participants and will evaluate whether del-brax can improve functional outcomes for people living with FSHD. 

Today’s announcement represents an important achievement in the effort to develop treatments that address the underlying cause of FSHD. We will continue to monitor developments and share updates with the community as more information becomes available. 

Read the Novartis press release ici.