Faced with breaking into markets led by larger companies, Biohaven turned to celebrity endorsements, Tiktok and racecar advertising to aggressively sell Nurtec ODT. Its digital-focused strategy has paid off (although not without some hiccups), making Nurtec ODT a notable example of a drug successfully launched by a smaller biotech company.

Biohaven’s success has drawn attention on Wall Street, where analysts marked the company as a potential target for acquisitions by larger pharmaceutical firms.

The deal announced with Pfizer falls short of that, likely playing a role in shares falling 17% in morning trading Tuesday, but still hands Biohaven $500 million and a share of any future ex-U.S. sales. Those royalties could be meaningful, as Pfizer, with its international reach and marketing muscle, is better positioned to capitalize on approvals abroad.

In Europe, a decision from the European Medicines Agency on Nurtec ODT’s approval is expected in the first half of 2022 and Biohaven noted in its Tuesday statement that several other regulatory authorities outside the U.S. are also reviewing the medicine.

Under the deal, Biohaven will continue to be responsible for further clinical development of Nurtec ODT, which is also known as rimegepant, while Pfizer will take over all overseas activity. In addition to the upfront payment and equity investment, Biohaven could receive as much as $740 million more in conditional payments should certain, unspecified milestones be achieved.

Pfizer will also get rights outside the U.S. to zavegepant, a successor molecule to rimegepant that works similarly but is being developed for intranasal delivery and as a soft-gel formulation.

Both drugs, known as CGRP inhibitors, are designed to block a cellular pathway that’s linked to migraine attacks. Nurtec ODT was the second oral CGRP inhibitor approved in the U.S., after AbbVie’s Ubrelvy, and was cleared first as a treatment for migraines already in in progress.

In May of this year, the Food and Drug Administration expanded its approval to include preventive use, putting Nurtec ODT in competition with injectable anti-CGRP drugs sold by Amgen, Eli Lilly and Teva Pharmaceutical.

According to Biohaven, Nurtec ODT has a 57% share of the oral CGRP market in the U.S., versus Ubrelvy’s 43% share. In September, AbbVie won FDA approval for another oral migraine drug called Qulipta.