Pfizer Inc. /zigman2/quotes/202877789/composite PFE -0.91% has agreed to buy Global Blood Therapeutics Inc. /zigman2/quotes/206019615/composite GBT +0.04% in a deal valued at $5.4 billion, the companies said Monday, confirming a report by the Wall Street Journal. Pfizer will pay $68.50 a share in cash for Global Blood Therapeutics, which has one of few approved treatments for sickle-cell disease, a painful inherited blood disorder that most affects people of African, Middle Eastern and South Asian descent. The acquisition "complements and further enhances Pfizer's more than 30-year heritage in rare hematology and reinforces the company's commitment to SCD by bringing expertise and a leading portfolio and pipeline with the potential to address the full spectrum of critical needs in this underserved community," Pfizer said in a statement. The news sent Global Blood Therapeutics shares up 4.3% premarket. Pfizer will finance the deal using cash on hand.