Seattle Genetics Lymphoma Drug Gets Boxed Warning on Brain Infection Risk

Seattle Genetics Inc. (SGEN) said its Hodgkin lymphoma drug Adcetris will carry a new boxed warning, the strictest U.S. caution, about a risk of dangerous brain infections.

Patients taking the medicine may develop a rare, potentially fatal condition known as progressive multifocal leukoencephalopathy or PML, the Bothell, Washington-based company said today in a statement. The revised label also will warn against using Adcetris with the cancer drug bleomycin because of risks of lung toxicity.

“Although PML in lymphoma patients can be caused by factors such as underlying disease and prior therapies that affect the immune system, a contributory role of Adcetris cannot be excluded,” Thomas Reynolds, Seattle Genetics’ chief medical officer, said in the statement.

Seattle Genetics declined 5.2 percent to $17.49 at 1:55 p.m. New York time.

Three patients have developed PML during treatment with Adcetris, the Food and Drug Administration said today in a drug safety communication. Symptoms may include mood changes, confusion, memory loss, weakness on one side of the body, and changes in vision, speech or walking. About 2,000 people worldwide have received Adcetris since its approval in August, the FDA said.

Adcetris, known chemically as brentuximab, is Seattle Genetics’s first product. Sales of the medicine may surpass $275 million in 2014, according to the average estimate of three analysts surveyed by Bloomberg.

To contact the reporter on this story: Molly Peterson in Washington at mpeterson9@bloomberg.net

To contact the editor responsible for this story: Adriel Bettelheim at abettelheim@bloomberg.net