Pfizer will spend about $5.4 billion to buy Global Blood Therapeutics as the pharmaceutical giant continues to invest some of the cash influx reaped during the COVID-19 pandemic.

Pfizer said Monday that the acquisition will boost its capabilities in rare hematology. Global Therapeutics makes Oxybryta tablets for treating sickle cell disease. Oxbryta sales were about $195 million last year.

The latest deal follows Pfizer's $11.6 billion acquisition of Biohaven, which the companies announced in May, and a $6.7 billion acquisition of Arena Pharmaceuticals announced last December.

Pfizer also announced in April a smaller acquisition to buy the privately held ReViral Ltd., which is developing a treatment for respiratory syncytial virus.

Pfizer Inc.'s top-selling COVID-19 vaccine and treatment have left the New York City drugmaker flush with cash to spend on an acquisition feel. The vaccine and treatment brought in more than $16 billion combined just in the recently completed second quarter.

Aamir Malik, the company's chief business innovation officer, told analysts recently that Pfizer was "leaving very few stones unturned" in looking for expansion opportunities. Malik said Pifzer was looking for deals that will speed up growth in the back half of the decade and can add substantial value either scientifically or commercially.

"I think we're very excited about the opportunities that are ahead of us and the flexibility that our balance sheet gives us to pursue those," he said during a call to discuss second-quarter results.

Pfizer will pay $68.50 per share in cash for each share of Global Blood Therapeutics.

Both companies' boards have approved the deal, which still needs regulatory approval and approval from GBT shareholders.

Shares of Global Blood Therapeutics Inc., based just outside San Francisco, rose 4% before the opening bell. Shares of Pfizer were essentially flat.