Seattle Genetics' (Nasdaq: SGEN) big day has arrived, as it has won FDA clearance to start selling its first new drug on the U.S. market after 14 years in business.

The company has received FDA clearance to start marketing brentuximab vedotin (Adcetris) as a new treatment for U.S. patients with a pair of rare lymphomas -- Hodgkin's disease and anaplastic large-cell lymphoma. The drug was given approval under the faster-than-usual six-month review cycle the FDA sometimes grants to potentially lifesaving therapies, and the official word came a little bit faster than the agency's legal review deadline of Aug. 30. The regulatory action was really no surprise, since Seattle Genetics won a 10-0 approval recommendation from an FDA advisory panel last month.

"Early clinical data suggest that patients who received Adcetris for Hodgkin lymphoma and systemic anaplastic lymphoma experienced a significant response to the therapy," said Richard Pazdur, the director of the FDA's cancer-drug review office, in a statement.

The FDA approval is the biggest moment in the history of Seattle Genetics, a company that was founded in 1997 and has run up a deficit of more than $546 million to get to this point, according to its most recent quarterly report.

The company's new drug represents a significant step ahead for both the science of antibody drug development and for patients with these two lymphomas. The drug combines the targeting capability of a genetically engineered antibody with an attached toxin that gives the antibody much more potent tumor-killing punch. This sort of "empowered antibody" approach has been pursued by scientists for more than three decades, but Seattle Genetics is only now in position to create what could be the first commercial hit from this class.

The drug showed startling effectiveness in clinical trials, providing significant tumor shrinkage in 75% of patients with relapsed forms of Hodgkin's disease in a clinical trial, and in about 86% of patients with anaplastic large-cell lymphoma. Researchers are still following patients to see how long those responses really do last, and to what extent they may help people live longer. The most common side effects found in clinical trials were a depletion in infection-fighting white blood cells, nerve damage in the fingers and toes, fatigue, nausea, and anemia, among other effects, according the statement from the FDA.

Seattle Genetics issued a brief statement after the FDA announcement. "Bringing a new product to the market is a significant milestone for Seattle Genetics in fulfilling its mission to improve the lives of people with cancer," said Clay Siegall, the company's co-founder and CEO.

The company didn't discuss one of the key facts investors will want to know immediately about the new product -- its price. Most analysts expect that the drug will end up costing more than $100,000 per patient, as it is given to patients in a series of intravenous infusions once every three weeks. Seattle Genetics said it plans to discuss more of its commercial plans on a conference call with investors at 8:30 a.m. ET on Aug. 22.

Luke Timmerman is the National Biotech Editor of Xconomy and the editor of Xconomy Seattle. E-mail him at [email protected] or follow him on Twitter at twitter.com/ldtimmerman.

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