Sirnaomics cleared to start first trial of RNAi lead in cancer

Cancer cells in electron microscope scan
The gene-silencing drug is also being tested to prevent and treat scarring. (Max Pixel/CC0)

Gene-silencing specialist Sirnaomics has been cleared to start trials of its STP705 drug in bile duct cancer, its first oncology indication.

The FDA has approved the biotech’s application to test the RNA interference (RNAi) candidate—which targets TGF-β1 and COX-2—in patients with bile duct cancer (cholangiocarcinoma, or CCA), adding to an earlier green light for a trial of the drug as a scar-reducing treatment.

The biotech says STP705 downregulates cancer-associated fibroblast (CAF) activity within the tumor microenvironment, inhibiting tumor formation. It was given orphan status for CCA and a fibrotic disease affecting the bile duct, primary sclerosing cholangitis (PSC), last year.

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The approval comes shortly after the regulator approved the first-ever drug in the category—Alnylam’s rare disease therapy patisiran—and is another indicator of the rapid emergence of RNA-targeting drugs in the biopharma sector.

Sirnaomics’ founder and CEO Patrick Lu, Ph.D., said the patisiran approval “validates the RNAi class of therapeutics and it is our belief that the industry will see great enthusiasm and expanded discovery and development of novel RNAi therapeutics for many disease applications.”

The Gaithersburg, Maryland-based biotech has been working on RNAi therapeutics since its formation more than a decade ago, and it raised $25 million from Chinese investors in a third-round financing in June.

At the time, the company said it planned to have two clinical trials running before the end of the year, and it plans to move ahead quickly with STP705 in The U.S., Europe and China, where it has a longstanding partnership with Guangzhou Xiangxue Pharma.

Sirnaomics’ Chief Medical Officer Michael Molyneaux, M.D., said the clearance to start trials in CCA is important, as this is “a devastating form of liver cancer with very high mortality and no effective therapy.”

It is the second most common hepatic primary malignancy, accounting for 15%-20% of all liver cancer cases. It is particularly common in Asia, although its incidence has increased quickly in the West in recent years, with around 5,000 new cases reported in the U.S. every year.