Ionis and Otsuka report positive Phase 3 results for FUS-ALS treatment

Ionis Pharmaceuticals and Otsuka Pharmaceutical have announced positive topline results from the Phase 3 FUSION trial evaluating ulefnersen, an investigational treatment for FUS-ALS. The study met its primary endpoint, demonstrating a statistically significant improvement in functional impairment and survival compared to a placebo (p=0.0005).

The trial utilized a joint rank analysis assessing time to death or permanent ventilation, time to rescue, and changes in the ALS Functional Rating Scale Revised (ALSFRS-R) score. Ulefnersen also showed statistically significant improvements in secondary endpoints, including changes in serum neurofilament light chain (NfL) levels and time to the earliest occurrence of death, permanent ventilation, rescue, or withdrawal due to disease progression.

FUS-ALS is a rare, rapidly progressing form of amyotrophic lateral sclerosis caused by mutations in the fused in sarcoma (FUS) gene. Currently, there are no approved treatments that target the underlying genetic cause of this condition. Following these results, Otsuka plans to engage in discussions with the FDA to explore expedited regulatory approval pathways.