Gaithersburg, Maryland-based Viela Bio, a company developing treatments for autoimmune and severe inflammatory diseases including COVID-19 lung damage, will be acquired by Dublin, Ireland-based Horizon Therapeutics in a deal worth nearly $3.1 billion.

News of the acquisition sent Viela Bio stock up more than 50% Monday. Viela Bio went public three years ago as a company spun off by Gaithersburg-based MedImmune.

Under terms of the acquisition, Horizon Therapeutics will pay $53 per share for Viela Bio’s outstanding stock in cash. The acquisition is expected to close by the end of the first quarter.

Horizon Therapeutics gains Viela Bio’s drug Uplizna, the only FDA-approved treatment for neuromyelitis optica spectrum disorder — a rare, severe autoimmune disease that attacks the optic nerve, spinal cord and brain stem.

Viela Bio also has experimental treatments in clinical trials COVID-19 related lung injury, as well as treatments for neuromuscular disease, lupus and other autoimmune and inflammatory diseases.

Viela Bio had $2.3 million in sales in its third quarter, all from Uplizna. It posted a quarterly loss of $37.6 million.