FRANKFURT- Singapore's state investor Temasek and other investors are injecting $250 million into German biotech company BioNTech, which is developing an experimental vaccine against the coronavirus with pharmaceutical giant Pfizer.

The investment, which BioNTech said was via a private placement, reflects heightened investor interest in the race to develop an agent that will stop the pandemic and sent shares in biotech firms such as Moderna and Novavax soaring this year.

U.S.-listed shares in the German company jumped almost 15% to their highest since March 19 on the news. They have surged more than 80% so far this year against the Nasdaq biotech index's gain of 12%.

BioNTech, which went public on Nasdaq in October last year, said the investors would purchase about $139 million in ordinary shares and $112 million in 4-year mandatory convertible notes.

It has said it expects first clinical data on its COVID-19 vaccine development programme known as BNT162 this month or in July.

The transaction would increase the number of BioNTech shares outstanding by 2.6 million from 226.8 million shares as per end of March, resulting in a combined stake of 1.1% for the investor group once all notes are converted.

BioNTech, which is also working on personalised cancer vaccines, would not say how much of the total is attributed to Temasek. Temasek would also not comment.

The investment adds to Temasek's healthcare assets that include Singapore biotech firm and COVID-19 treatment developer Tychan, British biotech firm Orchard Therapeutics and Irish drug delivery firm Aerogen.

Life sciences and agribusiness made up 7% of Temasek's holdings in the year to March 2019, up from 3% in the year to 2015.

BioNTech and Pfizer launched testing programmes involving humans in April and May.

Domestic rival vaccine developer CureVac, in which the German government is taking a 23% stake, is planning an initial public offering in the United States next month. U.S. peer Translate Bio has attracted France's Sanofi as an investor in a deal worth as much as $2 billion. 

BioNTech, which awarded the rights to BNT162 in China to Shanghai Fosun 600196.SS under a March collaboration deal, is competing with CureVac as well as U.S. biotech firms Moderna MRNA.O and Translate Bio in the race to develop messenger-RNA vaccines.

(Additional reporting by Anshuman Daga in Singapore and Thyagaraju Adinarayan in London; editing by Thomas Seythal and Emelia Sithole-Matarise) ((ludwig.burger@thomsonreuters.com; +49 69 7565 1311; Reuters Messaging: ludwig.burger.thomsonreuters.com@reuters.net))