UPDATED: Google backs $75M A round for Stanford's immuno-oncology spinout Forty Seven

Stanford's Irv Weissman

Stanford's Irv Weissman and a close group of colleagues have been lionized in recent years for their work on CD47, a molecule found on the surface of many tumors that guards against their destruction. Backed by grants, they have pushed their anti-CD47 antibody Hu5F9-G4 into two early-stage studies. And today they're spinning out the mission and the IP that backs them up into a startup--dubbed Forty Seven--that has gained a $75 million commitment from a group of investors that includes GV, Google's independent ($GOOG) venture arm.

Four years ago, the scientists' work demonstrating the potential of a CD47 drug spawned headlines around the world. And their field has only heated up steadily since the work was unveiled. Forty Seven plans to pursue their monotherapy work, now in Phase I, along with a cocktail approach that uses approved drugs like rituximab, cetuximab and trastuzumab as well as the checkpoint inhibitors that have begun to emerge on the market.

The scientists behind this program say that CD47 scrambles a key immune response that helps guard a range of tumor types by preventing a process called phagocytosis, in which the cancer cells are devoured by a phagocyte. That's what the researchers call a "don't eat me" effect.

The treatment also promises to whip up a T-cell attack on cancer "through cross-presentation of cancer cell antigens by macrophages, preventing engraftment of tumors expressing a cross-presented antigen into animals," the company said in a statement.

"Targeting CD47 integrates the adaptive and innate immune systems, creating synergy with existing cancer-specific antibodies like rituximab, cetuximab and trastuzumab through [antibody-dependent cellular phagocytosis], and potentially with T-cell checkpoint inhibitors through cross-presentation," noted Weissman.

"I kind of got seduced into this," says new CEO Jonathan MacQuitty, who retired from Abingworth at the beginning of last year only to jump back in to the business as an entrepreneur. Several opportunities came his way in the weeks after his departure from the venture group, and Forty Seven was a clear standout, particularly with the rush of excitement going around about checkpoint inhibition and combo strategies.

"This represented a sort of comparable, exciting opportunity on the innate side," he added. "It struck me as a really important thing." 

Now the Forty Seven team includes 10 staffers, which MacQuitty believes will swell to around 25 or 30 by the end of this year as the biotech pursues potential partnering talks with pharma. And later this year they'll have their first solid look at safety as well as tumor responses from the early studies, which have now recruited more than 20 patients. 

One of the key safety issues that's being tracked, he adds, is that the anti-CD47 approach for cancer could also threaten aging red blood cells. So making sure they have a carefully targeted therapy will be supremely important.

The first half of the $75 million round is in the bank, with the rest on tap when needed. The biotech is being backed by GV, Google's venture arm, and the round was led by Lightspeed Venture Partners (which is largely focused on IT) and Sutter Hill Ventures with participation from Clarus Ventures.

Alongside Weissman, the biotech's scientific founders include Ravi Majeti, Mark Chao and Jens Volkmer, who have all been working on CD47 for the past 6 years.

The mix of high-profile scientific founders, a promising new approach on cancer tied to checkpoint inhibition and deep-pocket investors are classic ingredients in the biotech startup world these days. What's unusual about Forty Seven, though, is that the company is already in the clinic with a lead drug, with plans to build a pipeline behind it. The IP handed over to the company includes new immune checkpoint inhibitors and cancer-specific antibodies.

Forty Seven isn't alone in the anti-CD47 space. Tiny Toronto-based Trillium Therapeutics ($TRIL) has also been pursuing the same target, and recently started a Phase I in relapsed or refractory hematologic malignancies. But the biotech has a market cap of only $53 million. The stock is down 5% this morning.

- here's the release