Trading of Aduro BioTech shares was halted earlier today as the drug maker said patients with advanced pancreatic cancer taking a combination of its immunotherapies in a clinical trial did not fare as well as those on standard chemotherapy.
Due to the disappointing results, Berkeley, CA-based Aduro (NASDAQ: ADRO) will shelve its work on third-line pancreatic cancer—that is, in patients who haven’t responded to at least two other kinds of treatment for what is one of the deadliest forms of cancer. Aduro CEO Stephen Isaacs said on a conference call today that the failed trial should not be seen as a referendum on the rest of the company’s cancer programs. “A negative outcome in this indication does not reflect negatively on the viability of the platform,” he said.
The announcement came before the market opened, and Aduro shares were halted. They opened at $7.50, down 30 percent from Friday’s close of $10.69. After trading resumed, shares recovered about half their losses to close Monday at $8.91.
Aduro is working on multiple types of cancer immunotherapy, medicines that aim to stimulate a patient’s immune system to overcome cancer’s tricks in evading the body’s defenses. One of the drugs in the failed combination reported today, dubbed CRS-207, is based on the bacterium Listeria, which Aduro renders non-infectious and engineers to mimic certain traits of cancer cells.
Aduro combined CRS-207 with a second immunotherapy called GVAX Pancreas, a vaccine made of modified tumor cells meant to add an extra immune boost. Patients receiving both did not fare as well as either those who received CRS-207 alone, or those who were supposed to receive chemotherapy alone. Roughly 70 patients received treatment in each arm of the trial.
Aduro officials said today that the results of CRS-207 alone—the best amongst the three patient groups—were “intriguing” but not enough to test further in the same patient setting. They also said that a majority of the patients who were supposed to get chemotherapy ended up on different kinds of therapy, which might have muddied the final results.
In a research note, Leerink Swann biotech analyst Seamus Fernandez called the results “disappointing and largely uninterpretable.”
One big problem was that the study wasn’t blinded. The patients who were informed they would be in the chemotherapy arm “started to look for other options,” said Dirk Brockstedt, Aduro’s executive VP of research and development. “There’s an inherent bias from patients who want immunotherapy treatment.”
Brockstedt said Aduro needs to “appropriately design” future trials that compare chemotherapy to immunotherapy, including its program to treat mesothelioma, a type of cancer that mainly affects the lungs.
Aduro should have plenty of cash to power through the setback. At the end of March the drug developer reported having more than $400 million in the bank. Aduro went public last year soon after locking up Novartis as a partner. Novartis paid an unusually high upfront of $250 million for another kind of immunotherapy, known as stimulator of interferon genes, or STING, that at the time had not yet been tested in humans. Novartis recently began the first-ever STING trial, which triggered a $35 million payment to Aduro.
Aduro will also push ahead with a Phase 2 trial testing CRS-207, GVAX, and Novartis’s nivolumab (Opdivo) in second-line pancreatic cancer.
Photo courtesy of Joe Flintham via Creative Commons.