Gaithersburg, Maryland-based Novavax has struck a deal to sell as many as 200 million doses of its still-unapproved COVID-19 vaccine to the European Commission for an undisclosed sum.

The agreement covers the purchase of up to 100 million doses of the vaccine with the option for an additional 100 million doses through 2023.

Novavax stock rose as much as 15% Wednesday morning on the news. Its stock has gained almost 70% year to date.

Novavax expects to submit its COVID vaccine to the European Medicines Agency for approval this fall.

While not approved, the Novavax vaccine has done well in large human trials. In a Phase 3 clinical trial with 30,000 adults in the U.S. and Mexico, it demonstrated 100% protection against moderate and severe disease, and 90.4% overall efficacy. In a Phase 3 clinical trail in the United Kingdom with 15,000 adults, it showed an overall efficacy of 89.7% and more than 96% efficacy against the original strain of the virus.

“With clinical data from our trials showing strong efficacy against variants of concern and variants of interest, we believe that our vaccine candidate will play a critical role in the effort to help control the pandemic in the EU and other regions in the world,” said Novavax CEO Stanley Erck.

Novavax has production agreements for its vaccine with multiple vaccine manufacturers in 10 countries.

“As new coronavirus variants are spreading in Europe and around the world, this new contract with a company that is already testing its vaccine successfully against these variants is an additional safeguard for the protection of our population. It further strengthens our broad vaccine portfolio, to the benefit of Europeans and our partners worldwide,” said Ursula von der Leyen, president of the European Commission.