The U.S. Food and Drug Administration has approved Cephalon Inc.’s injectable drug, Treanda to treat chronic lymphocytic leukemia.

Chronic lymphocytic leukemia, or CLL, is a slowly progressing blood and bone marrow disease. Over time, the CLL cells multiply and replace normal lymphocytes in the marrow and lymph nodes. CLL signs and symptoms usually develop slowly. Some CLL patients may have no signs or symptoms in the early stages of the disease and may have little or no change to their health for many years.

CLL more often hits older adults with an average age of 70 and is more common in men than in women.

According to the American Cancer Society, more than 15,000 new cases of the rare disease will be diagnosed in the United States this year.

“Treanda is an important new treatment for patients with chronic lymphocytic leukemia, and this first-cycle approval by FDA represents a significant milestone in the growth of our oncology business. With a strong pipeline of near- and longer-term opportunities, Cephalon Oncology is poised to deliver therapies that target both hematologic cancers and solid tumors for patients in need of new options,” said Dr. Lesley Russell, Executive Vice President, Worldwide Medical and Regulatory Operations, Bizjournals.com reports.

The approval was granted after Cephalon submitted a study of 301 previously untreated CLL patients who were randomly assigned to receive Treanda or another chemotherapy treatment called chlorambucil. According to the results of the trial, fifty-nine percent of patients responded to Treanda compared with 26 percent who were treated with the other drug. Also, 8 percent of patients administered Treanda had a complete remission of their leukemia, compared with less than 1 percent in the other group.

The side effects of Treanda are similar to those inducted by other chemotherapy drugs, including fewer white blood cells, nausea, anemia and vomiting.

Cephalon expects Treanda to be available for U.S. physicians and patients in April. The company would not disclose the drug’s price until it is launched, Jenifer Antonacci, Cephalon’s representative said.

For Cephalon, launching Treanda could bring a much-needed boost. The company has seen its share price plunge about 29 percent since June, largely because of slowed prescription growth of Provigil, a therapy prescribed for narcolepsy, sleep apnea, and shift-work sleep disorder. Last month, shares hit a 52-week low of $56.20.