Firm tests therapy on leukemia

Seattle Genetics said Tuesday it has initiated a 60-patient clinical trial of an experimental cancer therapy for chronic lymphocytic leukemia (CLL).

SGN-40, a genetically engineered monoclonal antibody, is already being studied for multiple myeloma and non-Hodgkin's lymphoma in other early trials.

The Bothell company also said SGN-40 received "orphan drug" designation for CLL from the Food and Drug Administration. The designation, for treatment of relatively rare diseases, means Seattle Genetics will have seven years of market exclusivity if the drug is approved.

The company's stock lost 8 cents, or 1.6 percent, to close at $4.93 Tuesday. It fell 3 more cents in after-hours trading.