(Bloomberg) -- Pfizer Inc. is in advanced talks to buy Global Blood Therapeutics Inc., the maker of a therapy for sickle-cell disease, for about $5 billion, the Wall Street Journal reported. 

The New York-based drug giant is looking to finalize a deal in the coming days, the Journal reported, citing people familiar with the matter who asked not to be identified. Bloomberg News had reported earlier this week that the biotech was drawing takeover interest from large pharmaceutical companies.

Global Blood shares gained as much as 52% Friday in New York after being briefly halted for volatility. Shares of Bluebird Bio Inc., which is developing a sickle-cell therapy, gained 16% as of 12:52 p.m. Pfizer fell 0.9%. 

Global Blood’s Oxbryta is approved by the US Food and Drug Administration to treat sickle-cell, a hard-to-treat, painful disease that most commonly affects Black people.

Pfizer representatives didn’t immediately respond to a request for comment. A spokesman for South San Francisco, California-based Global Blood said the company doesn’t comment on market rumors or speculation. 

(Updates with shares in third paragraph.)

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