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start to exhibit some of the same properties as cancer cells and get “eaten,” which the antibody therapy might hasten. But Weissman said that in primate tests, anemia occurred only in extremely high doses of the therapy, and then only temporarily. The blood system adjusted quickly to replace the lost red blood cells with new, young cells that aren’t affected by the anti-CD47 treatment.
In experiments transplanting human tumors into mice, Weissman noted that the antibody on its own successfully treated a range of cancers, then offered a standard biomedical caveat: “But that’s human tumors in mice.”
Forty Seven will continue to test the antibody on its own, but it will spend a good deal of its capital testing it in concert with other cancer-fighting antibodies such as rituximab (Rituxan) and trastuzumab (Herceptin), as well as checkpoint inhibitors, which don’t work well if a patient’s T cells aren’t already activated. By starting the macrophage feast, Hu5F9-G4 could help rev T cells into action, making checkpoint inhibitors more effective. That’s the theory, at least. Dozens of drug developers, it seems, want to pair their experimental drugs with checkpoint inhibitors, which themselves are already being combined and tested. Competition will be fierce, and potential costs of the treatments have raised alarms.
There are others going after CD47 as a cancer target, as well, such as Trillium Pharmaceuticals in Toronto, which announced three weeks ago that it had dosed its first patient in its first clinical trial.
Forty Seven will continue the two Stanford-sponsored Phase 1 clinical trials, start new combination trials this year and next year, and move two new programs, not targeting CD47, toward the clinic.
The strategy of academic researchers doing the so-called “translational” work—getting a drug program ready for clinical trials and perhaps even starting a trial or two—echoes Juno Therapeutics (NASDAQ: JUNO), the Seattle biotech that emerged in late 2013 with clinical trials already running at three research institutions and $120 million in funding.
The Weissman-led team received its CIRM money in two batches. First was an $18.8 million grant in 2009 for earlier work on the antibody program, then came $11.6 million more in late 2013 for the push into clinical trials.
Of the second grant, $5.1 million has not yet been dispersed. Forty Seven is in the process of taking charge of the grant-funded programs, says chief business officer Gibbs. That means the company would be eligible for the remainder of the CIRM cash and responsible for payments back to California taxpayers as it moves the work forward.
The first $500,000 in company revenue, either from licensing deals or product sales, are exempt from sharing, but after that “small percentages” of revenue—exact amounts depend on various scenarios—would flow back to California’s general fund, according to CIRM’s Gibbons. Gibbs declined to discuss the details but said, “There are definitely provisions for economics to flow back to CIRM. We’d be taking those on and honoring them.”