Ionis reports positive Phase 3 ALS trial results

• Ionis Pharmaceuticals (NASDAQ:IONS) reported positive topline results from its Phase 3 FUSION trial evaluating ulefnersen in patients with FUS-ALS.
• The trial met its primary endpoint, showing a statistically significant improvement compared with placebo using a joint analysis of function and survival outcomes.
• Ionis and Otsuka plan to discuss the results with regulators and evaluate potential submission pathways for ulefnersen.

Ionis Pharmaceuticals (NASDAQ:IONS) and Otsuka Pharmaceutical reported positive topline Phase 3 results for ulefnersen, an investigational RNA-targeted medicine for FUS-ALS.

The FUSION trial met its primary endpoint, showing a statistically significant improvement versus placebo in a joint rank analysis measuring functional impairment and survival outcomes through Day 505.

“Ulefnersen is the first investigational medicine to demonstrate a statistically significant benefit in a Phase 3 trial using a prespecified joint-rank analysis that combines assessments of function and survival,” said Ionis Pharmaceuticals Executive Vice President and Chief Development Officer Holly Kordasiewicz, Ph.D.

The companies reported statistically significant improvements in secondary measures, including serum neurofilament light chain levels and time to death, permanent ventilation, rescue treatment, or withdrawal due to disease progression.

Ionis discovered and developed ulefnersen, which targets the genetic cause of FUS-ALS, while the company previously developed QALSODY, a treatment for another rare genetic form of ALS.

Meanwhile, Otsuka licensed ulefnersen from Ionis in 2024 under a collaborative development and licensing agreement, with Ionis eligible for regulatory and sales milestone payments and tiered royalties on net sales.