Shares in Argenx rose after the European pharmaceutical company reported positive results from the phase 3 trial of Efgartigimod for the treatment of autoimmune myositis.

In early morning trading, shares were up 8% at 788.40 euros. Year to date, shares have risen 10%.

The company said Monday that patients demonstrated greater improvement both statistically and clinically at week 52 versus placebo.

Efgartigimod was well-tolerated by patients during the study, the company added.

"The patient response to efgartigimod was durable and multidimensional: separation from placebo emerged early and held through a full year of treatment, with a treatment effect of comparable magnitude in immune-mediated necrotizing myopathy and dermatomyositis," Chief Medical Officer Luc Truyen said.