ZymoGenetics Kidney Cancer Drug Shrinks, Stabilizes Tumors in Sickest Patients
ZymoGenetics (NASDAQ: ZGEN) is getting out of the business of developing cancer drugs, but it may have at least one potential valuable asset to put up for sale. The Seattle-based biotech company said its IL-21 drug was able to shrink and stabilize tumors in a small clinical trial of some of the sickest patients with kidney cancer.
The drug, IL-21, was given in combination with a marketed drug from Bayer and Onyx Pharmaceuticals, sorafenib (Nexavar), to 33 patients who had relapsed after at least one or two rounds of prior therapy. The experimental combo caused tumors to shrink in 21 percent of patients, and keep tumors from spreading for a median of 5.7 months. The most common side effects were low phosphate levels and rash, and the treatment was considered tolerable in an outpatient setting, researchers said today at the American Society of Clinical Oncology meeting in Orlando.
The results “point to a meaningful benefit of IL-21 when used in combination with a targeted therapy,” said John Thompson, an oncologist at the University of Washington and Seattle Cancer Care Alliance, in a company statement.
Of course, the study didn’t have a control group, so future trials would need to be run to show how much better this regimen might be than some other combination. But researchers see potential in IL-21 and Nexavar in combination because they are designed to have different ways of working. IL-21 is a genetically engineered copy of a cytokine that’s supposed to stimulate killer T cells and Natural Killer cells of the immune system to destroy malignant or infected cells. Sorafenib is a kinase inhibitor that interferes with molecules that are involved in forming blood vessels to tumors, and that control overactive cell proliferation.
The results being presented at ASCO look a little more promising than an interim look at the trial that ZymoGenetics presented last October at a scientific meeting in Geneva, Switzerland. Since then, however, a lot has happened to the company to put a damper on this program.
Last month, ZymoGenetics cut one-third of its workforce, 161 employees, and dropped its cancer research program in order to consolidate its resources on its core strength in immunology. The company is hoping to boost sales of its lone marketable product, recombinant thrombin for surgical bleeding, and conserve its cash so that it doesn’t have to tap the equity markets again. It is actively looking to outlicense the IL-21 program, and has already unloaded a number of other early-stage cancer drug programs that were sitting on the shelf, waiting for more resources to test whether they work.