GBT lines up for a $124M IPO with a pill for sickle cell

Global Blood Therapeutics, a graduate of Third Rock Ventures' startup academy, set terms for an IPO worth as much as $124 million, looking to raise money for its oral sickle cell disease program.

The company, headquartered in South San Francisco, is looking to move 6 million shares at $16 to $18 each. GBT has set aside another 900,000 shares for its underwriters, led by Goldman Sachs and Morgan Stanley, to cover overallotments. The 4-year-old biotech plans to make its debut on the Nasdaq exchange under the symbol "GBT."

GBT's plan is to put about $50 million of its IPO proceeds into GBT440, an oral drug designed to interrupt the root cause of sickle cell disease, now working through a Phase I/II trial. The disease takes shape when hemoglobin in red blood cells fuses together into long, sharp strands, malforming cells and causing deadly blockages in vessels. GBT440 works by binding to those hemoglobin molecules before they stick together, encouraging them to oxidize and thereby reducing the chances that they sickle, the company believes.

The drug's Phase I/II study began in December, and GBT is enrolling up to 128 patients to first establish GBT440's safety before expanding into an efficacy trial.

Beyond its lead candidate, GBT is at work on an early-stage oral therapy for the rare hereditary angioedema, which results in dangerous bodily swelling. The biotech is earmarking $15 million of its potential IPO haul to fund that drug's preclinical development and move toward a Phase I trial.

GBT got off the ground with a $40 million Series A in 2012 and raised $48 million more in January. Third Rock owns a 63% stake in the company, while Fidelity, which joined its Series B round, holds 13.2%.

- read the filing