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The Bothell, WA-based biotech company (NASDAQ: SGEN) said this morning that about half of patients who failed on previous treatments had their tumors shrink after taking its experimental SGN-35 drug. More than one-third (10 out of 27 patients) had their tumors completely disappear, according to research presented today at ASCO. This finding is from a study of patients who got SGN-35 infusions once a week in a variety of low doses to assess safety. Most side effects were mild in severity, researchers said.
The data are from the first of three phases of clinical trials, and the study had no control group, so it’s impossible to say for sure how much better patients did on this drug than they might have done on some other treatment. But the findings do verify results from a previous study of 44 patients that looked at the drug when given once every three weeks. SGN-35 is attempting to carve out a niche in the emerging field of “empowered antibodies,” which are designed to seek out cancer cells, spare healthy ones, and (here’s the special part) unload an extra lethal dose of a toxin to kill the tumor cells.
—Calistoga Pharmaceuticals. The Seattle-based biotech company is working on blocking the prized PI3 kinase target, which is associated with tumor growth. Its drug candidate, CAL-101, is supposed to be different from the rest in the pack because it hits a specific variation of the PI3 kinase known as the delta isoform, which is thought to be associated with blood cancers like lymphomas and leukemias. The Calistoga drug showed an ability to shrink tumors in 6 of 12 patients studied in an initial clinical trial, including some responses at very low doses.
A good break went Calistoga’s way before the ASCO conference when one of its competitors, South San Francisco-based Exelixis, scored a big partnership with Sanofi-Aventis, potentially worth more than $1 billion, to co-develop its PI3 kinase blocker. Calistoga’s chief business officer, Cliff Stocks, said before the meeting that the deal verified the valuation it was placing on its technology, and will certainly provide fodder for a lot of partnership talks, Stocks says.
—ZymoGenetics (NASDAQ: ZGEN) had some positive news from a trial of IL-21, a kidney cancer drug it is looking to unload as it gets out of the cancer research business. The drug, when given in combination with Bayer and Onyx Pharmaceuticals’ sorafenib (Nexavar), was able to shrink tumors in 21 percent of patients, and keep them from spreading a median time of 5.7 months. This finding was from a small trial of 33 patients, and there was no control group to provide a frame of reference, but the patients were generally quite sick, having failed to respond to at least one or two prior rounds of therapy.
The company’s immunotherapy, Stimuvax, was found to be well-tolerated by patients over long-term usage, according to data presented by Charles Butts of the Cross Cancer Institute in Edmonton, Canada. A mid-stage trial of patients with lung cancer found that 10 patients have been treated with Stimuvax now for more than five years, and eight continue to get it. There is no evidence that the immune-stimulator is causing the immune system to go overboard and start attacking healthy tissue, a condition otherwise known as autoimmune disease, the company said.
Other preliminary results were reported on Oncothyreon’s drug for blocking the PI3 kinase. This drug candidate, PX-866, was taken as a once-daily pill by 26 patients at a variety of doses to get a read on its safety. Of 24 patients evaluated, six patients whose disease had spread previously had their tumors stabilize, the company said. This is a competitive field of research, and Oncothyreon says its drug is different because it is an irreversible blocker of the protein, meaning it binds with it and won’t let go as long as the drug is active in the bloodstream.