ZymoGenetics’ Kidney Cancer Drug, Taken with Nexavar, Shrinks Tumors in Relapsed Patients

Xconomy Seattle — 

ZymoGenetics has some minor good news coming out today. The Seattle biotech company said that a study showed its genetically-engineered protein drug, IL-21, was able to help shrink and stabilize kidney tumors in combination with another targeted drug, even in patients whose disease relapsed after prior therapy.

The preliminary results show that three of 18 patients (17 percent) on IL-21 and Bayer and Onyx Pharmaceuticals’ sorafenib (Nexavar) had their tumors shrink at least by one-fourth, and seven of 13 patients who finished three courses of therapy had their tumors stabilize or shrink, researchers said today at the EORTC-NCI-AACR Symposium on Molecular Targets and Cancer Therapeutics in Geneva, Switzerland.

The study didn’t have a control group, so it’s impossible to say how much better (or worse) this treatment combination might be than any other alternative. ZymoGenetics (NASDAQ: ZGEN) says the combination regimen “appears to compare favorably” with other clinical trials, which showed that sorafenib on its own causes tumor shrinkage for just 2 percent of patients who are this sick. The company will know whether it has hit the main goal of the study, to see whether the combination therapy can slow the spread of kidney cancer, in the first half of 2009. Kidney cancer kills an estimated 13,000 people each year, according to the American Cancer Society. So even though sorafenib and Pfizer’s sunitinib (Sutent) have brought progress to patients with this disease, there’s always room for improvement.

“We continue to see promising anti-tumor effects from the combination of IL-21 and Nexavar in patients with renal cell cancer,” said Nicole Onetto, ZymoGenetics’ chief medical officer, in a company statement. “We look forward to final results.”

Like any combination cancer treatment, especially in very sick patients who have failed prior therapy, the IL-21 and sorafenib in tandem have side effects. Most side effects were mild, and consistent with what the drugs do when given on their own, but whenever you combine medicines, doctors will be on the watch for “overlapping toxicities.” Serious side effects were reported in six patients, including cases of acute kidney failure, rash and dehydration, and low white blood cell counts, ZymoGenetics said.

The two drugs are designed to work differently. 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.

ZymoGenetics is looking for a ray of good news, since it has struggled to gain momentum in the marketplace with recombinant thrombin (Recothrom), its first marketed product, to control surgical bleeding. The company is also expecting to show some positive preliminary results from pegylated interferon lambda for hepatitis C at the American Association for the Study of Liver Disease next month in San Francisco. No matter—its stock has been trashed, down 57 percent this year to $5 at yesterday’s close. So any little bit of positive news at this point might help.

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