San Diego’s Polaris Moves to Late-Stage Test of Drug for Liver Cancer and Other “Arginine-Dependant” Tumors

4/27/11Follow @bvbigelow

Bor-Wen Wu says he had the North Star in mind in 2006 when he founded San Diego’s Polaris Group, a small holding company with a promising lead drug candidate for treating liver cancer, malignant melanoma, and other related cancers. As an explorer in science, Wu says, “I need a North Star to tell me where to go.”

Yet the path Wu has followed has been anything but a sure and constant course. In his quest to develop the drug ADI-PEG 20, Wu has formed eight companies since 2002 that are affiliated with Polaris; raised more than $60 million from individual investors in Taiwan; and battled to retain control of ADI-PEG after paying millions to acquire a predecessor company, Phoenix Pharmacologics of Lexington, KY.

Despite a sometimes-circuitous path, though, Wu has kept the Polaris Group focused on a distant goal. The FDA recently approved the company’s plans for a late-stage clinical trial of ADI-PEG 20, an enzyme also known as pegylated arginine deiminase. ADI-PEG 20 is incredibly effective in breaking down arginine, an amino acid that is critical to the growth of hepatocellular carcinoma—the primary type of liver cancer.

Among cancer drugs in Phase 3 trials, Wu boasts, “We’re not the first in class. We’re the only one in the class. There’s nothing in the rear-view mirror.”

A study published last year in the British Journal of Cancer estimates there are 500,000 new cases of hepatocellular cancer diagnosed worldwide annually, with a five-year survival rate of less than 10 percent in the United States and Europe. Polaris, which contends the liver cancer is far more prevalent in Asia, estimates that worldwide deaths from hepatocellular carcinoma is closer to 700,000 people a year, with more than 330,000, or nearly half, in China.

ADI-PEG 20 represents an especially hot area of cancer research, which has focused on finding ways to starve tumors by depriving them of key nutrients. In the case of liver cancer, Wu says a key genetic mutation that triggers hepatocellular carcinoma coincides with the specific gene that makes arginine in normal cells. The company says the correlation is more than 70 percent in the patients studied so far. As a result, most liver tumor cells are unable to manufacture their own arginine and depend on some other source of … Next Page »

Bruce V. Bigelow is the editor of Xconomy San Diego. You can e-mail him at bbigelow@xconomy.com or call (619) 669-8788 Follow @bvbigelow

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