Annexon (ANNX) reported "rapid recovery and durable benefit" for patients in the phase 3 trial of tanruprubart, a potential targeted therapy for Guillain-Barre Syndrome,

The trial showed a 2.4-fold higher likelihood of improvement at week eight versus placebo in 241 patients, the company said Tuesday in a statement, with the results presented at the American Academy of Neurology annual meeting in San Diego.

Key findings showed that tanruprubart led to a 14-fold improvement in mobility at week one and twice as many patients had no limitations by week 26, the company said.

Shares of the company rose 3.3% in recent after-hours trading, paring earlier gains.