By Colin Kellaher


Shares of Spero Therapeutics Inc. nearly doubled in premarket trading Thursday after the clinical-stage biopharmaceutical company agreed to license tebipenem HBr, its late-stage antibiotic asset, to U.K. pharma major GSK PLC in a deal potentially worth hundreds of millions of dollars to Spero.

Under the agreement, Spero will receive an upfront payment of $66 million from GSK, which also will invest $9 million to buy 7.45 million Spero shares at around $1.21 apiece, a 47% premium to Wednesday's closing price of about 82.2 cents for the Cambridge, Mass., company.

Spero said it is also eligible for up to $525 million in future milestone payments, along with royalties on sales.

Spero shares were recently up 92% to $1.58 in premarket trading Thursday.


Write to Colin Kellaher at


(END) Dow Jones Newswires

September 22, 2022 06:15 ET (10:15 GMT)

Copyright (c) 2022 Dow Jones & Company, Inc.
Historical Stock Chart
From Nov 2023 to Dec 2023 Click Here for more Gsk Charts.
Historical Stock Chart
From Dec 2022 to Dec 2023 Click Here for more Gsk Charts.