By Chris Wack


Ionis Pharmaceuticals Inc. shares fell 12% to $30.90 after the company said a study for tofersen missed its primary endpoint.

The company said its partner Biogen reported topline results from its placebo-controlled study of tofersen, an investigational antisense medicine being evaluated for people with superoxide dismutase 1 amyotrophic lateral sclerosis.

Tofersen didn't meet its primary endpoint, but trends favoring tofersen were seen across multiple secondary and exploratory measures of disease activity and clinical function.

Biogen said a pre-specified integration of data from the study and its ongoing open-label extension study reinforced the findings, and showed that early tofersen initiation led to less decline across multiple measures including motor function, respiratory function, muscle strength, and quality of life in people with SOD1-ALS.

Biogen, which licensed tofersen from Ionis in 2018, said it is actively engaging with regulators, the medical community, patient advocacy groups and other key stakeholders to determine next steps.

Biogen said it will expand eligibility for its ongoing early access program to all people with SOD1-ALS in countries where such programs are permitted by local regulations and future access may be secured. If a path forward for tofersen isn't established or if another controlled trial is required by regulators, Biogen said it could revise or discontinue the EAP.


Write to Chris Wack at


(END) Dow Jones Newswires

October 18, 2021 10:40 ET (14:40 GMT)

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