* BofA, JP Morgan win global coordinator roles -sources
* Sale could be worth as much as $800 million-sources
* IPO eyed in Q4 or early 2020-sources (Adds BioNTech comment)
By Arno Schuetze and Ludwig Burger
FRANKFURT, March 12 (Reuters) - BioNTech, Europe's largest unlisted biotech firm by staff numbers, has hired banks to prepare for an initial public offering (IPO) worth as much as $800 million as early as this year, people familiar with the plan told Reuters.
Bank of America and JP Morgan have been retained as global coordinators for the planned listing on the U.S. Nasdaq exchange some time in the fourth quarter or in early 2020, the sources said.
The transaction could value the firm at roughly $4 billion, though deal terms and timing could be subject to change, they added.
BioNTech, which has previously said it was looking at a future public listing, said it would continue to explore various financing options, including a possible IPO, within the context of its financing needs and the market environment.
The two banks declined to comment.
Mainz-based BioNTech raised $270 million from investors in a January 2018 financing round, valuing the firm at $2.3 billion at the time.
It specialises in so-called messenger RNA (mRNA) molecules that instruct human cells to produce therapeutic proteins that trigger an immune response against cancer or infectious diseases.
Among its other areas of development are gene therapies and nano-particles for cancer immunotherapy.
Biotech investors Thomas and Andreas Struengmann, who sold their generic drugs business Hexal to Novartis in 2005, are majority shareholders in BioNTech, and other owners include German venture capital investor MIG Fonds.
Pfizer last year agreed to pay the German biotech firm up to $425 million in an alliance to develop more effective influenza shots and also acquired a smaller stake in the company.
BioNTech competes in the race for mRNA therapies with groups such as Massachusetts-based Moderna, whose market value peaked at $7.7 billion last month, as well as Belgium's eTheRNA and domestic rival CureVac.
Apart from Pfizer, the emergent mRNA field has seen drugmakers such as AstraZeneca, Eli Lilly and Sanofi partner up with biotech firms.
BioNTech has previously attracted alliance partners including Roche's Genentech, Eli Lilly, Sanofi, Genmab and Bayer Animal Health. (Reporting by Arno Schuetze and Ludwig Burger Additional reporting by Patricia Weiss Editing by Caroline Copley, Jane Merriman and Alexander Smith)