A two-and-a-half-year-old biotech with an adenosine-targeted checkpoint drug plans to move into pivotal trials in near record time. At its corporate R&D day in July, Corvus Pharmaceuticals in Burlingame, California, announced plans to validate its adenosine A2A receptor blocking agent in renal cancer patients next year, even though the small-molecule drug, CPI-444 has been in clinical testing only since early 2016." We've been on a terrific trajectory," says Corvus CEO Richard Miller." The target was so ripe for investigation." It didn't hurt that immuno-oncology is currently an irresistible investment. Corvus, founded in 2014, has raised $180 million from two private financings and a 2016 initial public offering, and is partnering with Roche/Genentech in S. San Francisco on early trials. CPI-444 is one of six adenosine-targeted drugs in early clinical trials (Table 1), with several more in preclinical pipelines.[illus. 1]

The adenosine surge was long in coming." I've been trying to push adenosine for the last 15 years" for cancer, with little success until now, says Joel Linden, an immunologist at the La Jolla Institute for Allergy and Immunology in California. Adenosine is one of many normal immune regulators, or checkpoints, hijacked by tumors to evade immune attack, and adenosine blockade has the potential to work in patients who fail treatment with the five anti-PD-1 and PD-L1 checkpoint inhibitors that are now approved for eight cancer types. But although experts consider Corvus' early clinical results promising, the stock market has punished the company. If they are to survive, Corvus and its competitors must clinically distinguish this immunotherapy drug class from at least a dozen others also targeting the 80-90% of eligible patients who don't respond to (or who relapse following) anti-PD-1 treatment alone.