This week the US Food and Drug Administration (FDA) approved ofatumumab (Arzerra) for the treatment of chronic lymphocytic leukemia (CLL) that is not responding to fludarabine (Fludara) or alemtuzumab (Campath). The drug, made by GlaxoSmithKline and Genmab, was given fast-track approval, meaning the companies must conduct more studies to prove the drug is effective.

CLL accounts for about one-third of all leukemias. Leukemias are cancers of white blood cells that start in the bone marrow and can spread to other parts of the body such as the spleen, lymph nodes, and liver. Compared to other types of leukemia, CLL usually grows slowly.

Treatment options vary, depending on whether CLL is causing any symptoms and the history of the patient. Many CLL patients who have already been treated with the chemotherapy drug fludarabine try alemtuzumab, a monoclonal antibody that can help their immune system destroy cancer cells, as a second-line treatment.

Ofatumumab is also a monoclonal antibody that helps stimulate the immune system to fight cancer cells. It works by binding to a specific protein found on both normal and malignant B cells (B cells are a type of white blood cell).

The FDA's approval of ofatumumab was based on encouraging results from a single-arm (in other words, all the patients got the same treatment) study of 59 patients whose CLL had come back or not responded to other treatments. Forty-two percent of the patients responded to ofatumumab. The average response time was 6.5 months. The drug's safety was also evaluated in a group of 181 CLL patients.

Common side effects included a decrease in normal white blood cells, pneumonia, fever, cough, diarrhea, lower red blood cell counts, fatigue, shortness of breath, rash, nausea, bronchitis, and upper respiratory tract infections. The most serious side effect was an increased chance of infections, including some that could be life-threatening.

GlaxoSmithKline plans additional studies of the drug, which may be available by prescription within the next month.

Click here to read the FDA's press release. For more information about CLL, click here.

Reviewed by: Members of the ACS Medical Content Staff