Philadelphia, Pennsylvania: The US Food and Drug Administration yesterday approved the Cephalon drug Treanda (bendamustine hydrochloride) to treat chronic lymphocytic leukemia, a rare cancer that affects the blood and bone marrow.

According to American Cancer Society estimates provided by the drugmaker, Chronic Lymphocytic Leukemia (CLL) is expected to strike some 15,000 people in the United States this year.

In a statement, Cephalon stated that in a trial of 301 patients that compared Treanda to an already approved chemotherapy drug, Treanda recipients had better response rates and longer progression-free survival. Treanda works by damaging the DNA in cancer cells, causing these cells to die. It is expected to hit the U.S. market in April.

According to Cephalon, the treatment was granted orphan drug status by the FDA, which offers companies exclusive marketing rights in return for drugs developed for rare diseases.