Bothell-based Alder BioPharmaceuticals, which is seeking Food and Drug Administration approval for a migraine prevention treatment, has agreed to be acquired for $18 a share and potential future payments. The buyer is a Danish company, Lundbeck, that Bob Azelby, Alder’s president and chief executive officer, described as “a global leader in neuroscience research with products registered in more than 100 countries.”

Including a $2-per-share payment if European drug regulators approve the therapy, the deal is worth $1.95 billion, the companies said in a press release Monday.

Alder, which had 202 employees at year-end, went public in 2014. It priced its IPO at a disappointing $10, but the shares soared above $50 the following year. The stock had mostly traded in the low teens this year before Monday’s news sent it leaping more than 80 percent to close at $18.50.

Alder submitted its preventative treatment for patients with frequent migraines in February, and the FDA is expected to respond by early next year.