Global Blood Therapeutics, Inc. (GBT)

Global Blood Therapeutics was a biopharmaceutical company in South San Francisco that focused on sickle cell disease, an inherited blood disorder that mostly affects people of African, Middle Eastern and South Asian descent. Its approach was to develop drugs that keep sickle hemoglobin from clumping, which deforms red blood cells and blocks blood flow.

The company was formed in 2011 with backing from a venture firm and went public on Nasdaq in August 2015 under the ticker GBT. Its lead drug, voxelotor, binds to hemoglobin to stabilize it in its oxygen-carrying form. The company raised money through several stock offerings to fund large clinical trials of voxelotor, including the Phase 3 HOPE study that measured improvements in hemoglobin levels in patients with sickle cell disease.

In November 2019 the FDA granted accelerated approval to voxelotor, sold as Oxbryta, as a once-daily oral tablet for sickle cell disease. Oxbryta later gained approval for younger children and in Europe, and GBT also advanced inclacumab, an antibody aimed at reducing pain crises, and a next-generation hemoglobin modulator later called osivelotor.

In August 2022 Pfizer agreed to buy GBT for $68.50 per share in cash, an enterprise value of about $5.4 billion. The deal closed in early October 2022 and GBT shares were removed from the Nasdaq Global Select Market. GBT's programs were folded into Pfizer's rare disease and hematology operations. The price was a sizable premium to where GBT had traded before reports of a possible sale.

In September 2024 Pfizer voluntarily withdrew Oxbryta from markets worldwide after newer data raised safety concerns, a major setback for the acquisition. Pfizer trades on the NYSE under the ticker PFE. The withdrawal came less than two years after the deal closed and led Pfizer to halt related trials in sickle cell disease.