AbbVie Buying Cancer Drug Startup Stemcentrx for $10.2 Billion by Dan Primack @FortuneMagazine April 28, 2016, 7:27 AM EDT E-mail Tweet Facebook Linkedin Share icons Pharma giant AbbVie Inc. this morning said it will acquire privately held cancer drug developer Stemcentrx in a blockbuster deal that could be worth up to $10.2 billion. Not only would that make this one of the largest biotech acquisitions in recent memory, but also one of the five biggest sales ever of a venture capital-backed company. AbbVie ABBV will pay $5.8 billion up-front in a combination of cash ($2 billion) and stock. Then there is up to another $4 billion in cash-based earn-outs, based on the achievement of various milestones. That brings the deal value to $9.8 billion, but Stemcentrx also has cash on hand that would be returned to shareholders, thus giving the company an entire enterprise value of around $10.2 billion. The transaction is expected to close later in Q2. San Francisco-based Stemcentrx currently has five drug candidates in clinical trials, each focused on targeting and eliminating the cancer stem cells that are responsible for tumors. The furthest along is designed to treat small-cell lung cancer, which accounts for between 10% and 15% of all lung cancers, and is one of the most likely to return after initial treatment. Last August, Stemcentrx published Phase I clinical trial results that showed, among other things, an unusually high percentage of sustained tumor size reductions among small-cell lung cancer patients who had initially responded to treatment, but then later relapsed. “The addition of Stemcentrx and its late-stage compound Rova-T provide AbbVie with a unique platform in solid tumor therapeutics and complement our leadership position in hematologic oncology,” said AbbVie chairman and CEO Richard Gonzalez in a statement. “We believe the acquisition of Stemcentrx will strengthen and accelerate our ability to deliver innovative therapies that will have a remarkable impact on patients’ lives.” Stemcentrx was founded in 2008 by CEO Brian Slingerland, a former investment banker, and chief scientific officer Scott Dylla, who previously had been a senior scientist with Oncomed Pharmaceuticals OMED . Stemcentrx initially raised a few small rounds of VC funding from firms like Western Technology Investment and Artis Ventures, before securing a $42 million Series D round in 2012 at around a $300 million valuation. That deal included a $30 million lead investment by Founders Fund, which would eventually become Stemcentrx’s largest outside shareholder, investing a total of around $300 million (making it the Peter Thiel-affiliated firm’s largest single investment, even larger than its commitments to Elon Musk’s SpaceX). “We weren’t space experts and wouldn’t have done SpaceX if Elon wasn’t running it,” explains Brian Singerman, a partner with Founders Fund. “This was similar for us in that we’re also not cancer experts, but the founders were so strong and the science was so sound.” Singerman adds that Founders Fund brought three research oncologists and three clinical oncologists into due diligence sessions before making its initial investment. “Scientists are usually very conservative, but we knew that Stemcentrx really had something when these oncologists told us, ‘Well, it won’t obviously not work.'” Stemcentrx would go on to join the “unicorn” club in late 2014 and then be valued at around $5 billion in an August 2015 investment co-led by Fidelity Investments and Sequoia Capital. Fidelity recently marked down that investment by 37.76%, although the AbbVie deal represents a gain even before any of the earn-out is realized.